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wide-field variability surveys: a 21st-century perspective 22nd Los Alamos Stellar Pulsation Conference Series meeting San Pedro de Atacama, Chile, Nov. 28 – Dec. 2, 2016 ABSTRACT BOOKLET Abstracts of talks are listed in the same order as they appear in the program. Posters are listed in alphabetical order, according to the presenting author’s family name. In both cases, the presenting author’s name is shown in boldface type. TALKS (Abstracts of talks are listed in the same order as they appear in the program. The presenting author’s name is shown in boldface type.) T1 The Impact of Large-Scale, Long-Term Optical Surveys on Pulsating Star Research Igor Soszyński The era of large-scale photometric variability surveys began a quarter of a century ago, when three microlensing projects - EROS, MACHO, and OGLE - started their operation. These surveys initiated a revolution in the field of variable stars and in the next years they inspired many new observational projects. Large-scale optical surveys multiplied the number of variable stars known in the Universe. The huge, homogeneous and complete catalogs of pulsating stars, such as Cepheids, RR Lyrae stars, or long-period variables, offer an unprecedented opportunity to calibrate and test the accuracy of various distance indicators, to trace the 3D structure of the Milky Way and other galaxies, to discover exotic types of intrinsically variable stars, or to study previously unknown features and behaviors of pulsators. I will present recent findings on various types of pulsating stars obtained from the optical large-scale surveys, with particular emphasis on the OGLE project which currently offers the largest photometric database among surveys for stellar variability. T2 Synergies between Transient Surveys and Variable Star Research A. J. Drake The age of very widefield synoptic surveys is upon us. For the past decade optical surveys such as CRTS, PanSTARRS, and PTF have regularly covered tens of thousands of degrees of visible sky. These surveys have uncovered an ever growing zoo of transient astrophysical phenomena. The archival data legacy of these surveys is now being harvested to reveal the myriad of variable stars. In the next decade this field will continue grow as even larger surveys move to deeper exploration of the time domain. I will present results from our initial steps along this road. T3 OGLE Cepheids in the Milky Way Andrzej Udalski OGLE Galaxy Variability Survey is a long-term sky survey covering over 2000 square degrees along the Galactic plane, conducted as a part of the OGLE-IV program. Results of the search for Galactic Cepheids in the data collected in the years 20132016 will be presented. T4 Pulsating Star Products from the Palomar Transient Factory: Ultra-Long Period Cepheids in M31 and RR Lyrae in Kepler Field Chow-Choong Ngeow The Palomar Transient Factory (PTF) and its successor, the intermediate PTF (iPTF), are wide-field synoptic sky surveys aimed to detect transients. PTF/iPTF uses a robotic 48inch Schmidt telescope, also known as the P48 Telescope, located at the Palomar Observatory to carry out the surveys. The P48 Telescope is equipped with a wide-Field mosaic camera that consists of eleven 2K x 4K CCDs with a field-of-view of 7.3 degreesquared. Nominal observations of PTF/iPTF was carried out in either g or R filters. With an exposure time of 60-second, the PTF/iPTF data can reach to a depth of ~20.5 mag. Even though the main science goal for PTF/iPTF is to detect various type of transients, the synoptic nature of the surveys can also be used for the study of variable stars. In this Presentation, I will first give a brief introduction to PTF/iPTF, followed by the two pulsating stars studies using the PTF/iPTF data: the Ultra-Long Period Cepheids (ULPC) in M31 and the RR Lyrae in Kepler Field. For the formal study, we searched the M31's ULPC using PTF imaging data, and follow-up the candidates with other telescopes. Our finding revealed that there are only two ULPC in M31. I will give a brief implication of our finding in distance scale studies. For the later study, I will present our on-going work to calibrate the metallicity-light curve relation in native PTF/iPTF R-band using the RRab stars in the Kepler Field. T5 Outward Bound: RR Lyr in the Outer Part of the Milky Way Halo Judith Cohen Branimir Sesar Anushka Asnodar the PTF and iPTF team We have isolated a large sample of RR Lyrae variables at distances beyond 50 kpc in the Milky Way halo from the Palomar Transient Facility database. We are using these to probe the density distribution in the outer halo out to about 100 kpc as well as the total mass of the Milky Way galaxy, which is still controversial and is important for near field cosmology. A spectroscopic program to obtain radial velocities for the most distant of these variables at the Keck Observatory now has vr for 112 outer halo RR Lyr, more than a third of which are beyond 80 kpc. We believe we have found one new outer halo structure. We discuss the potential and the issues of using RR Lyr for this purpose. T6 Blazhko Modulation in First-Overtone RR Lyrae Stars from the OGLE Collection Henryka Netzel Radoslaw Smolec and OGLE team Blazhko effect is a long-term quasi-periodic amplitude and/or phase modulation of pulsations of RR Lyrae stars. After its discovery in 1907 by Sergey Blazhko, its origin remains a mystery. This phenomenon has not been extensively studied in firstovertone (RRc) RR Lyrae stars yet. The Optical Gravitational Lensing Experiment (OGLE) is a source of excellent quality photometry for more than 10 000 RRc stars in the Galactic bulge. These stars were monitored regularly from 2010 in the fourth phase of the OGLE. Additionally, for some stars data from earlier phases of the OGLE project are available. Therefore the OGLE Collection of Variable stars is an excellent database to study longterm behaviour of period changes and Blazhko effect in a large sample of RRc stars. In this talk we present results of the first comprehensive study of Blazhko effect in RRc stars. Input sample for our analysis consists of almost 11 000 stars, for which we used six seasons of the OGLE observations spanning from 2010 to 2015. Incidence rate based on this study is around five per cent. High fraction of RRc stars show period changes, which are often irregular and can be confused with Blazhko effect. For these stars we used, if possible, observations from previous phases of the OGLE project to study longterm behaviour of pulsations. In Blazhko stars we detected both dublet and triplet structures in power spectra. Shortest modulation period is 5 days for a star with detectable triplet and below 5 days for a star with doublet only. We also detected quintuplets in some stars. Particularly interesting stars are these with multiple modulation periods. We also found modulated stars which show additional variability due to non-radial modes. All these findings in RRc stars, based on statistically significant sample, might shed new light on mysterious Blazhko phenomenon. T7 Synergies between Exoplanet Surveys and Variable Star Research Géza Kovács With the discovery of the first transiting extrasolar planetary system back to 1999, a great number of projects started to hunt for other similar systems. Because of the incidence rate of such systems was unknown and the length of the shallow transit events is only a few percent of the orbital period, the goal was to monitor continuously as many stars as possible for at least a period of a few months. Small aperture, large field of view automated telescope systems have been installed with a parallel development of new data reduction and analysis methods, leading to better than 1% per data point precision for thousands of stars. With the successful launch of the photometric satellites CoRot and Kepler, the photometric precision increased further by one-two orders of magnitude. Millions of stars have been analyzed and searched for transits. In the history of variable star astronomy this is the biggest undertaking so far, resulting in photometric time series inventories immensely valuable for the whole field. In this review we briefly discuss the methods of data analysis that were inspired by the main science driver of these surveys and highlight some of the most interesting variable star results that start to impact the field. T8 Pulsating Stars in SuperWASP Daniel Holdsworth SuperWASP is one of the largest ground-based surveys for transiting exoplanets. To date, it has observed over 31 million stars. Such a extensive database of time resolved photometry holds the potential for extensive searches of stellar variability, and provide solid candidates for the upcoming TESS mission. Previous work by e.g. Smalley et al (2011), Holdsworth et al (2014), Paunzen et al (2015) have shown that the WASP archive provides a wealth of pulsationally variable stars. In this talk I will provide an overview of the SuperWASP project, present some of the published results from the survey, and some of the on-going work to identify key targets for the TESS mission. T9 Pulsating White Dwarfs in Large Surveys Kepler Oliveira (S. O. Kepler) The Sloan Digital Sky Survey has allowed us to increase the number of known white dwarfs by a factor of five and consequently the number of known pulsating white dwarfs also by a factor of five. It has also allowed us to discover new types of variable white dwarfs, as the variable hot DQs, and to study the new class of Extremely Low Mass white dwarfs. With the Kepler Mission, it has been possible to discover new phenomena, the outbursts present in a few pulsating white dwarfs. T10 A Survey of Pulsating DA and DB White Dwarfs with the Whole Earth Telescope Judith Provencal Mike Montgomery Harry Shipman WET Collaboration White dwarfs represent the end point of stellar evolution for the majority of stars. As such, they are excellent astrophysical laboratories. They are structurally simple, with electron degenerate cores surrounded by thin surface layers of helium and/or hydrogen. The g-mode pulsations provide a window into their internal structure. The Whole Earth Telescope has been conducting a long-term survey of pulsating white dwarfs with the goal of providing an empirical map of convection parameters across the DA and DB instability strips. We discuss our current results, and present interesting things we've noticed in the course of our investigation. T11 Time-Series Surveys and Pulsating Stars: The Near-Infrared Perspective Noriyuki Matsunaga I'm going to review current and future near-infrared time-series surveys. The potentials and limitations of infrared surveys will be discussed with a particular emphasis on importance of characterizing interstellar extinction. T12 Pulsating Stars and the VVV Survey Dante Minniti The VVV Survey is mapping the innermost regions of the Milky Way in the near-IR passbands ZYJHKs, using the VISTA telescope at ESO Paranal Observatory. In this talk I will concentrate on the latest results regarding pulsating variable stars. In particular, we discovered a dozen RR Lyrae in the Galactic center, which has implications for the formation of the nuclear star cluster. Also, I will present a new globular cluster discovered in the inner Milky Way disk using RR Lyrae stars. Finally, I will conclude with the future perspectives offered by the VVVX, which is the extension of the VVV survey to a larger area and time baseline. T13 Multiwavelength Theoretical and Observed Light Curve Parameters of Cepheid and RR Lyrae Variables Anupam Bhardwaj Shashi Kanbur Marcella Marconi Lucas Macri Marina Rejkuba We analyse the multiwavelength theoretical (UBVRIJKL) and observed (VIJHK3.6/4.5) light curves of Cepheid variables using the Fourier decomposition and principal component analysis methods. The theoretical Cepheid light curves are obtained using the full amplitude, nonlinear, convective hydrodynamical models for chemical compositions relative to Cepheids in the Galaxy (Y=0.28, Z=0.02), Large Magellanic Cloud (Y=0.25, Z=0.008) and Small Magellanic Cloud (Y=0.25, Z=0.004). We studied the variation of light curve parameters with period, wavelength and metallicity. We observed a decrease in Fourier amplitude parameters and an increase in Fourier phase parameters with increasing wavelength at a given period for both theoretical and observed light curves. However, the amplitudes for the theoretical light curves are systematically higher than the observed amplitudes over entire period range. We found that for periods longer than about 20 days, the values of the Fourier amplitude parameters increase sharply for shorter wavelengths as compared to wavelengths longer than the J-band. The central period of the Hertzsprung progression was found to increase with wavelength in the case of the Fourier amplitude parameters and decrease with increasing wavelength in the case of phase parameters. We also observed a small variation of the central period of the progression between the Galaxy and LMC, presumably related to metallicity effects. We find two distinct populations in the first principal component for optical and near-infrared wavelengths. The VI-band principal components for Magellanic Cloud Cepheid models are consistent with observations. We also studied the theoretical light curves adopted from pulsation models of RR Lyraes for a wide range of the metal abundances (Z=0.0001 to solar abundant 0.02) in the optical (UBVRI) and near-infrared(JKL) bands and compared their light curve parameters with observed light curves from OGLE and VVV surveys. T14 Spitzer Observations of Large Amplitude Variables in IC1613 Patricia Whitelock I will discuss the large amplitude variables in the Local Group dwarf irregular galaxy, IC 1613, based on multi-epoch data from the Spitzer spacecraft. This uses observations obtained as parting of the SPIRITS (PI Mansi Kasliwal) and DUSTiNGS (PI Martha Boyer) collaborations. Although we detected Cepheid and supergiant variables, the majority of large amplitude sources are AGB stars. They have a range of initial masses and include hot bottom burning stars. These extensive datasets provide new insight on the infrared amplitudes period-luminosity relations. As such they are an important step on the road to understanding comparable data that JWST will obtain for more distant galaxies. T15 Pulsations and Declines in R Coronae Borealis Stars Geoffrey Clayton RCB stars form a class of cool, carbon-rich supergiants that have almost no hydrogen. They undergo extreme, irregular declines in brightness of up to 8 magnitudes due to the formation of thick clouds of carbon dust. Two scenarios have been proposed for the origin of an RCB star: the merger of a CO/He WD binary and a final helium-shell flash. RCB stars show periodic or semi-periodic light and radial velocity fluctuations due to both radial and non-radial pulsations. A number of RCB stars are now being studied with K2. A correlation between pulsation phase and the timing of dust formation has been found in several RCB stars. This relationship shows that the dust forms near the surface of the RCB star due to density and temperature perturbations caused by the stellar pulsations. The distribution on the sky and radial velocities of the RCB stars tend toward those of the bulge population but a much larger sample of stars is needed to determine the true population. In order discover more RCB stars, we have used a series of WISE IR colorcolor cuts, to produce a sample of several thousand candidates that may yield over 200 new RCB star identifications. Solving the mystery of how the RCB stars evolve will lead to a better understanding of other important types of stellar merger events such as Type Ia SNe. T16 Look Behind You! The Past Can Contribute Uniquely to the Future Elizabeth Griffin The surveys which are the chief foci of this meeting are almost exclusively concerned with recent and upcoming electronic surveys. But the practice of surveying the night sky is not new; one of the first coordinated observatory activities involved surveys, of various hues and sizes. For many decades the IAU itself paid tribute to that activity by supporting a special Commission for it. The wealth of past surveys will be described briefly. Though now regarded as limited in quality, early surveys carry date-stamps which enable their contents to add usefully, sometimes critically, to modern science. T17 LSST and Its Potential for Variable Star Research Melissa Graham Ž. Ivezić The Large Synoptic Survey Telescope (LSST) will be a large (6.7m effective aperture), wide-field (9.6 sq.deg. field-of-view) ground-based system designed to obtain deep photometric data in six broad bands (ugrizy, 320-1050 nm). Each sky position will be observed multiple times, with several hundred observations per band collected over the main survey area (20,000 sq.deg. with equatorial declination<+34.5 deg) during the anticipated 10 years of operations. The current observing strategy calls for about 10,000 sq.deg. of sky to be covered using pairs of 15-second exposures in two photometric bands spaced by about an hour within a night, and every three nights on average, with 5-sigma depth for point sources of r~24.5. The measured properties of newly discovered and known astrometric and photometric transients will be publicly reported within 60 sec after closing the shutter. I will briefly review the status of LSST construction project and will discuss opportunities for variable star research to be enabled by LSST. T18 Pulsating Star Research and the Gaia Revolution Laurent Eyer Gaia is currently observing variability behaviours in unprecedented ways. All instruments of Gaia will contribute to the description of variability phenomena. The astrometry, will provide absolute magnitudes, the BP and RP spectrophotometry will be able to derive colours. Astrometry combined with spectrophotometry is allowing to place the stars in the HR diagram. The RVS instrument will also be able to measure radial velocities. The time series of these different quantities will be able to determine how the magnitude, the colour, change during a pulsation cycle. The release scenario will be explained. The current strategy is to release the variability gradually during the mission, with more and more stars, with longer time series and more data types at each release. T19 The Hubble Catalog of Variables Kirill Sokolovsky Alceste Bonanos Panagiotis Gavras Maria Ida Moretti Ming Yang We aim to construct an exceptionally deep catalog of variable objects in selected Galactic and extragalactic fields visited multiple times by the Hubble Space Telescope with the same instrument/filter combination. While some of these fields were searched for specific types of variables before (most notably, the extragalactic Cepheids), we attempt a systematic study of the population of variable objects of all types at the magnitude range not easily accessible with ground-based telescopes. The variability timescales that can be probed range from hours to years depending on how often a particular field has been visited. For source extraction and cross-matching of sources between visits we rely on the Hubble Source Catalog (HSC) which includes 107 objects detected with WFPC2, ACS, and WFC3 instruments in at least one visit. The lightcurves extracted from the HSC are corrected for systematic effects by applying local zero-point corrections and are screened for bad measurements. For each lightcurve we compute variability indexes sensitive to a broad range of variability types. The indexes characterize the overall lightcurve scatter and degree of correlation between consecutive brightness measurements. Candidate variables in each field are selected as having variability index values significantly higher than expected for objects of similar brightness in the given set of observations. The candidates are inspected to distinguish true variables from objects with measurements corrupted by blending or imaging artifacts. The completeness of the variable object selection is evaluated through simulations. Our variability detection technique is applicable to other time-domain surveys. This work is supported by the European Space Agency (ESA) under contract No. 4000112940. T20 Cepheids with the Eyes of Photometric Space Telescopes László Molnár Aliz Derekas Emese Plachy Róbert Szabó László Szabados Space photometric missions have been steadily accumulating observations of Cepheids in recent years, leading to a flow of new discoveries. The four-year data of lone Kepler Cepheid, V1154 Cyg, revealed period jitter, modulation, granulation noise and the lack of solar-like oscillations. MOST discovered period doubling in the modulated Cepheid V473 Lyr, suggesting that modulation may have similar origins in RR Lyrae and Cepheid stars. And since the start of the K2 mission, Kepler already observed dozens of Cepheid stars in the regular campaigns, and covered the nearby galaxy IC1613 and the galactic bulge where hundreds of such variables reside, including many type II Cepheids, a class that was scarcely observed from space before. T21 Gaia’s Cepheids and RR Lyrae stars and the PL Relations Based on Tycho-Gaia astrometric Solution Parallaxes Gisella Clementini We have used parallaxes of Galactic Cepheids (Classical and Population II) and RR Lyrae stars published in Gaia Data Release 1 as part of the Tycho-Gaia Astrometric Solution (TGAS), along with literature (V, I, J, K) photometry and spectroscopy, to build: i) period-luminosity (PL) and period-Wesenheit (PW) relations for both classical and type II Cepheids; and ii) near-infrared PL, PL-metallicity (PLZ) and optical luminositymetallicity (Mv-[Fe/H])relations for the RR Lyrae stars, with zero points based on TGAS parallaxes. The classical Cepheids were selected as to remove known and suspected binary systems and further reduced by retaining only sources with sigma_Pi/Pi < 0.5. Similar cuts were also applied to both Type II Cepheids and a RR Lyrae stars. We present results from application of these TGAS-based relations to estimate the distance to the Large Magellanic Cloud. We also discuss the comparison of the TGAS parallaxes with Hipparcos and HST parallaxes as well as with parallaxes inferred from the Baade-Wesselink method and the theoretical model fitting of multi-band light curves. T22 Asteroseismology and Galactic Archaeology in the Era of Large Surveys Víctor Silva Aguirre Large spectroscopic and photometric surveys are strongly complimentary to the wealth of asteroseismic data delivered by the Kepler and K2 missions. Combined they can provide accurate properties of stars across the Galaxy and unveil the history of formation and evolution of the Milky Way. In this talk I present the first results in this field from the APOGEE and SAGA surveys, where we have measured for the first time the vertical age gradient in the galactic disk, constructed the age metallicity relation for the population, and determined the age difference between the thick and the think components of the disk. I discuss the tests currently underway to ensure the robustness of stellar properties from asteroseismology (ages in particular) and the future prospects for the field with the advent of the TESS and PLATO missions. T23 The K2 RR Lyrae Survey Róbert Szabó We have initiated a large survey with K2, to observe thousands of RR Lyrae stars along the ecliptic. The high photometric precision and the 80-90-day continuous coverage will allow us to investigate the light variation of these galactic structure tracer variable stars with an unprecedented detail. The survey will help us to conduct a thorough statistical study of RR Lyrae pulsation dynamics including old and recently discovered dynamical phenomena, like resonances, non-radial modes, period-doubling and the Blazhko-effect. In this talk I describe the survey, present the first results and discuss the prospects in the light of what the combination of the survey and LSST (and also Gaia) will have to offer in the context of galactic structure studies. T24 RR Lyrae Star Distance Scale and Kinematics from Inner Bulge to 50 kpc Andrey Dambis Leonid Berdnikov Eva Grebel Alexey Kniazev Ivan Katkov We compile the currently most complete sample of almost 5000 Galactic RR Lyrae variables with available radial-velocity and spectroscopic [Fe/H] measurements adopted from dedicated studies (about 440 stars), large-scale spectroscopic surveys (SDSS, RAVE, LAMOST, a total of over 4200 stars), and based on the results of our program aimed at acquiring spectra of relatively bright RR Lyrae variables carried out at South African Large Telescope yielded radial velocities and metallicities (~200 hitherto spectroscopically unexplored RR Lyraes). We complement the radial-velocity data for these stars with accurate proper motions from the upcoming Tycho-Gaia catalog and compute proper motions for fainter stars based on the UCAC4, URAT1, 2MASS, and WISE, and DSS Schmidt plate positions reduced to the frame defined by UCAC4 catalog. We further determine the mutually consistent preliminary distances to our RR Lyraes based on our recent calibrations (Dambis et al. 2013, 2014) applied to WISE infrared data, published photoelectric and CCD V-band data, reduced Catalina Sky Survey data, and our own photoelectric (more than 1200 multicolor measurements) and CCD (more than 40000 frames) photometry. We use the 3D velocity data obtained to perform a statistical-parallax analysis for a subsample of ~1000 RR Lyraes brighter than V=16m to refine the parameters of optical and IR period-metallicity-luminosity relations and adjust our preliminary distances. We use the kinematic data for the entire sample to explore the dependence of the halo and thick-disk RR Lyrae velocity ellipsoids on Galactocentric distance from the inner bulge out to R~50 kpc, probe the mass distribution in the Galactic halo, and estimate the distance to the Galactic center.. T25 Faint Variable Stars in the Milky Way dSph Satellites Kathy Vivas Mario Mateo Javier Alonso-García Alistair Walker David Nidever Pulsating variable stars below the horizontal branch provide an interesting tool to study the stellar population present in dSph galaxies. The region of the CMD may include not only main sequence stars of a young and/or intermediate age population but also blue stragglers from an old population. dSph galaxies contain stars that inhabit a different age/metallicity range than found anywhere else in the Galaxy and so offer the chance to study these faint variables from unique and otherwise hard to study populations. The combination of a large FOV camera such as DECam in a 4meter class telescope presents a unique opportunity to search for these variables in some of the satellites of the Milky Way. We discuss results obtained in Sextans and Sagittarius galaxies. T26 Pulsating Stars and the Virtual Observatory Juan Carlos Suárez Virtual Observatory is one of the most used internet-based protocols in astronomy. It has become somewhat “natural” to find, manage, compare, visualize and download observations from very different archives of astronomical observations with no effort. The VO technology beyond that is now being a reality for asteroseismology, not only for observations but also for theoretical models. This talk will give a brief description of the most important VO tools related with asteroseismology, as well as a rough outline of the current development in this field. T27 Stellar Astrophysics from the Evryscope: The First Simultaneous All-Sky High-Cadence Survey Octavi Fors Nicholas M. Law Jeffrey Ratzloff Daniel del Ser Henry T. Corbett The Evryscope is an array of 24 telescopes which covers a gigapixel-scale, instantaneous 8000-square-degree field-of-view at two-minute cadence. This telescope opens a new parameter space in time-domain astronomy, trading instantaneous depth (g~16mag) and sky sampling (~13”) for continuous coverage (97% survey time efficiency) of the largest sky area of any active survey. The system provides percent-level photometry at two minute cadences on bright (g<12) stars, with a per-exposure limiting magnitude of g~16 in a 100-degree declination range. The photometric performance improves to 5-7 mmags when a ~30minute binning is applied. The Evryscope team is using a list of 4500+ white dwarfs (WDs) candidates down to g=17 and Dec<+10deg to conduct a large-scale survey (>1000+ targets per night) for habitable planets transiting WDs. This exploration comprises the brightest, most nearby WDs, and with higher precision than past ground-based surveys and faster cadence than Kepler’s standard mode. With Evryscope simultaneously observing hundreds of WDs with better than 10% photometric precision in each two-minute exposure, its data set allows us to directly measure the population of small transiting objects around WDs. In addition, it enables the possibility of obtaining long-term measurements of WDs pulsations, eclipsing WD binaries and periodically variable WDs, and other objects which can constrain WDs fundamental physics. As the Evryscope is also building 1%-precision, many-year-length, high-cadence light curves for every accessible object brighter than g~16mag, its data set enables the discovery and characterization of a wide range of stellar variability, including measuring the mass-radius relation using by producing a complete inventory of eclipsing binary systems with orbital periods < 60 days, detecting young stars by their flare behavior, and detecting stellar merger events, accreting compact objects, and exotic pulsators. The examples of the first pulsations and variability detections from both specific WDs and synoptic stellar astrophysics surveys will be presented and discussed. The Evryscope was deployed at CTIO in May 2015. The telescope is fully operational, streaming raw imaging data per night at 109MB/sec, meaning 59TB of raw data have collected so far, totaling ~700,000 images. All data is stored and analyzed on-site by a high-speed server. Two more Evryscopes are planned to be deployed in near future: at Mount Laguna Observatory (collaboration with SDSU) and in the High Arctic (collaboration with NARIT and University of Toronto). T28 Challenges in the Automated Classification of Variable stars in Large Databases Matthew J. Graham With ever-increasing numbers of astrophysical transient surveys, new facilities and archives of astronomical time series, time domain astronomy is emerging as a mainstream discipline. However, the sheer volume of data alone - hundreds of observations for hundreds of millions of sources - necessitates advanced statistical and machine learning methodologies for scientific discovery: characterization, categorization, and classification. Whilst these techniques are slowly entering the astronomer’s toolkit, their application to astronomical problems is not without its issues. In this talk, we will review some of the challenges posed by trying to identify variable stars in large data collections, including appropriate feature representations, dealing with uncertainties, establishing ground truths, and simple discrete classes. T29 Compilation and Classification of Light-Curves Catalogues for HiTS Jorge Martínez Palomera Francisco Förster Pavlos Protopapas The High Cadence Transient Survey is an effort to characterize fast transient objects using high cadence, wide and deep observations, the data were taken using DECam at Blanco/CTIO. My work consist in generate catalogues of detected sources and build light curves of point-like, non-moving sources. The main goal is classify all variable objects using time series analysis, starting from feature extraction, build the training set using Transfer and Active Learning, to final classification with Machine Learning. We have about 2 millions light curves with data mainly in g and r band with a cadence of ~1.6 hours. I will present results about catalogues (photometry calibration, efficiency, limiting and completeness magnitude), light curves (main statistics), feature extraction and preliminary results of classification of variable sources. This is my PhD thesis research. T30 Studying Stellar Variability with a Decade of HATNet Observations John Hoffman Joel Hartman Gáspár Bakos The Hungarian-made Automated Telescope Network (HATNet) has been carrying out wideangle high-cadence photometric monitoring of the sky since 2004. Light curves have been generated for over 5 million stars with 9 < r < 14.5. The typical star has 10,000 observations, and the precision reaches 4 mmag per three minute cadence at the bright end. We report on our ongoing efforts to carry out a comprehensive study of stellar variability with these data using machine-learning techniques. T31 Finding Binaries from Phase Modulation of Pulsating Stars with Kepler Hiromoto Shibahashi Simon Murphy Tim Bedding We explore the detection limits of the phase modulation (PM) method of finding binary systems among multi-periodic pulsating stars. The method is an attractive way of finding non-transiting planets in the habitable zones of intermediate mass stars, whose rapid rotation inhibits detections via the radial velocity (RV) method. While oscillation amplitudes of a few mmag are required to find planets, many Scuti stars have these amplitudes. In sub-optimal cases where the signal-to-noise of the oscillations is lower, low-mass brown dwarfs (~13 MJup) are detectable at orbital periods longer than about 1 yr, and the lowest mass main-sequence stars (0.1-0.2 M) are detectable at all orbital periods where the PM method can be applied. We use purpose-written Markov chain Monte Carlo (MCMC) software for the calculation of the PM orbits, which offers robust uncertainties for comparison with RV solutions. Using Kepler data and ground-based RVs, we verify that these two methods are in agreement, even at short orbital periods where the PM method undersamples the orbit. We develop new theory to account for the undersampling of the time delays, which is also necessary for the inclusion of RVs as observational data in the MCMC software. We show that combining RVs with time delays substantially refines the orbits because of the complementarity of working in both the spatial (PM) and velocity (RV) domains simultaneously. Software outputs were tested through an extensive hare and hounds exercise, covering a wide range of orbital configurations including binaries containing two pulsators. T32 Survey-Invariant Variable Star Classification using Bayesian Domain Adaptation Pavlos Protopapas Supervised data mining and machine learning rely on the availability of labeled data. When sufficient training data is available, supervised models achieve high performance in many domains. However, labeled data is often much scarcer than unlabeled data and much more expensive and difficult to obtain. Moreover, when models that perform well in one setting are applied to data from a different but related domain –e.g. from a different population, a different geographical location, or a different instrument or sensor – performance often drops significantly. Additionally, the enormous rate at which unlabeled data is being generated greatly surpasses the rate at which labeled data becomes available. Domain adaptation aims to learn from a domain where labeled data is available, the 'domain', and through some adaptation perform well on a different domain, the 'target domain'. In this talk, I present a new probabilistic model that represents the source and target distributions as two Gaussian mixtures and finds a transformation between the feature spaces of the domains to transfer labeled data between them. Our approach allows working with data available in one domain as if it belonged to the other, enabling the training of models in the target domain from training sets adapted from the source domain. We evaluate our proposal in simulated data and the problem of variable star classification. In the latter, we use data from two different astronomical surveys with different characteristics in terms of sensor sensitivity, geographical location and atmospheric conditions, and data sampling frequency, among others. T33 The Impact of Gaia Parallaxes on Asteroseismic Inferences from Kepler Travis Metcalfe Orlagh Creevey et al. The Kepler space telescope yielded unprecedented data for the study of solar-like oscillations in other stars. The large samples of multi-year observations posed an enormous data analysis challenge that has only recently been surmounted. Asteroseismic modeling has also become more sophisticated over time, with better methods gradually developing alongside the improved observations. We have applied the latest version of the Asteroseismic Modeling Portal (AMP) science code to the full-length Kepler data sets for 57 stars, deriving reliable estimates of the stellar properties including a theoretical parallax for each target. We compare our predictions to the measured parallaxes from the first data release of Gaia, and we quantify the level of improvement in asteroseismic inferences when Gaia data are used to constrain the modeling. T34 The VVV Galactic Cepheid Program: A Journey to the Far Side of the Milky Way István Dékány Dante Minniti Gergely Hajdu Wolfgang Gieren Márcio Catelan Half of our Milky Way galaxy is located in a narrow stripe of the sky along the Galactic equator, disguised by extreme extinction and foreground stellar populations. Mapping these vast, distant Galactic regions using stellar tracers was impossible before the existence of deep infrared time-domain observations. Unique data from the VVV Survey now enables us to probe these regions using distant Galactic Cepheids, accurate standard candles and well-understood population tracers. Unlike velocity-distance techniques, these stellar beacons require no putative assumptions of the Galaxy’s kinematics, and they are also useful along the Galactic center sight-line. In the framework of the VVV Galactic Cepheid Program, we are conducting a deep census of both classical and type II Cepheids along the Galactic plane and toward the bulge. We employ these valuable beacons to probe the the far side of the disk, properties of the flared outer disk and the inner disk region in the bulge volume; and search for hitherto unknown satellites of the Milky Way beyond the far edge of its disk. By complementing photometry with kinematical and elemental abundance measurements of the Cepheids, we are aiming to probe the chemo-dynamical properties of the obscured inner bulge and the far side of the Galactic disk, and infer global properties of the Galaxy such as general symmetry, spiral arm configuration, abundance gradients, and bulk kinematics. T35 Pulsating Variable Stars and Large Spectroscopic Surveys Peter De Cat In the past decade, the research of pulsating variable stars has taken a giant leap forward thanks to measurements provided by space missions like MOST, CoRoT and Kepler. These missions have provided quasi uninterrupted photometric time-series with an ultra-high quality and a total length that is unachievable with Earth-based observations. However, many of the success stories could not have been achieved without ground-based spectroscopic follow-up observations. Indeed, spectroscopy has some important assets as it can provide (more) accurate information about: (1) stellar parameters like the effective temperature, surface gravity, metallicity, and abundances (that are mandatory important parameters for an in-depth asteroseismic study), (2) the radial velocity (that is important for the detection of binaries and for the confirmation of cluster membership, if applicable), and (3) the projected rotational velocity (that allows the study of the effects of rotation on pulsations). Fortunately, several large spectroscopic surveys are (becoming) available that can be been used for these purposes (like SEGUE, RAVE, APOGEE, and LAMOST). In some cases, (sub)projects have been initiated with the specific goal to complement the space-based photometry. In this review, several spectroscopic surveys are introduced and compared with each other. Their impact on pulsating variable star research is illustrated with some well-chosen examples. It highlights their potential both for in-depth studies of individual stars and as ground-based support for (future) space missions. T36 APOGEE and Pulsating Stars Steve Majewski The APOGEE survey, now in Phase 2 (APOGEE-2 in SDSS-IV) and soon to begin operations in Chile, is continuing to deliver high resolution, near-infrared H-band spectra of hundred of thousands of targets around the whole sky. Among the numerous primary goals of the main APOGEE-2 survey is both a large survey of RR Lyrae stars in the Galactic bulge as well as a continued focus on targets with asteroseismic data (described more fully in a separate talk by M. Pinsonneault) from the CoRoT, Kepler and K2 missions. However, by both chance and design, the APOGEE project has sampled a few other categories of pulsational variables, from hot blue varieties to Cepheids. The APOGEE instruments play a major role in plans for “After Sloan IV”, opening a variety of opportunities for further contributions to pulsational variable science, including all-sky and time-series spectroscopic surveys. T37 The LAMOST Spectroscopic Survey of Stars in the Kepler Field of View: Activity Indicators and Stellar Parameters Joanna Molenda-Zakowicz Antonio Frasca Peter De Cat Giovanni Catanzaro For 51,385 stars of spectral types ranging from B to M located in the Kepler field of view, we derived the atmospheric parameters (Teff, log g and [Fe/H]) and the radial velocities (RV). Our results have been based on the low-resolution spectroscopic observations obtained with the LAMOST facility in the framework of the LAMOST-Kepler project. The accuracy of the parameters derived from the LAMOST data are typically 10–15 km/s in RV, about 3.5 % in Teff, 0.3 dex in log g, and 0.2 dex in [Fe/H]. We notice a systematic difference of about 0.2 dex between spectroscopic and photometric metallicities which is consistent with earlier findings based on smaller data samples. The analysis of H alpha and Ca II-IRT fluxes which allowed us to detect 442 chromospherically active stars, one of which is a likely accreting object. Then, we made use of the precise rotation periods from the Kepler photometry and we studied the dependency of the chromospheric fluxes on the rotation rate for a quite large sample of field stars. Finally, we report on detection of stars variable in RV, stars with very high projected rotational velocity (v sin i > 150 km/s), and emission-line objects. T38 APOKASC 2.0: Asteroseismology and Spectroscopy of Red Giants Marc Pinsonneault The APOGEE survey has obtained and analyzed high resolution H band spectra of more than 10000 cool dwarfs and giants in the original Kepler fields, with up to 16,000 Kepler stars anticipated in the 4th Sloan Digital Sky Survey. Spectra for an additional 13,000 giants with K2 data will also be obtained. The APOKASC effort combines this data with asteroseismology, resulting in more than 7,000 stellar mass estimates for dwarfs and giants with high quality abundances, temperatures, and surface gravities, with many more anticipated. We highlight the main results from this effort so far, which include a tight correlation between surface abundances in giants and stellar mass, precise absolute surface gravity calibrations, and the discovery of unexpected stellar populations, such as young alpha-enhanced stars. We discuss grid modeling estimates for stellar masses and compare the absolute asteroseismic mass scale to calibrators in star clusters and the halo. Directions for future efforts are discussed. T39 Asteroseismology: The Kepler Revolution Tim Bedding Asteroseismology has entered a new golden age, thanks to wonderfully precise measurements being returned by NASA's Kepler mission. Kepler is a 0.9-metre space telescope that has been monitoring the brightness of more than 100,000 stars with extraordinary accuracy for more than four years. Its main goal is to discover extra-solar planets by detecting the small dips in light as they transit their parent stars. The mission has been spectacularly successful, with thousands of candidates reported. Meanwhile, Kepler's observations of oscillations in thousands of stars have led to a revolution in asteroseismology. Key results include detecting gravity modes in red giant stars and characterizing stars found to host exoplanets. Upcoming results from ESA's Gaia mission will add to the excitement, as will the launch next year of TESS, which is an all-sky follow-up mission to Kepler. T40 TESS and the Future of Asteroseismology from Space Hans Kjeldsen The Transiting Exoplanet Survey Satellite (TESS) is a NASA Explorer mission that will observe several hundred thousand stars at a cadence of 2 minutes, as well as generating Full Frame Images (FFI’s) at cadence of 30 minutes. TESS aims to do wide-field surveys with the fine photometric precision and long intervals of uninterrupted observation, as can only be done in a space mission. Compared to Kepler, TESS will examine stars that are generally brighter by 4-5 magnitudes over a FOV at each pointing that is larger by a factor of 25. TESS will observe at each pointing for 27 d, and the overlap between fields means that a given target will be observed continuously for between 27d and 355 d, depending on the ecliptic latitude. The TESS photometric data represent a unique resource for asteroseismic investigations of the global properties and internal structure of a large number of stars having a broad range of different types. Through investigation of a broad range of stars the asteroseismic investigation will substantially improve our understanding of general stellar evolution, and hence strengthen the use of such modelling to further constrain the properties and evolution of the stars and systems investigated in the TESS extrasolar planet program. In this talk I will discuss the asteroseismic part of the TESS projects which is organized under the TESS Asteroseismic Science Consortium (TASC). The goal of the TASC science program is to do asteroseismic characterization of planet-hosting stars, including mass, age and particularly radius as well as understanding general stellar properties, including stellar structure modelling and contributing to stellar characterization. I will also discuss the future of asteroseismology in relation to future spaces missions in particular the ESA PLATO mission. T41 Asterosesimology of Main-Sequence Solar-Like Stars with K2 Mikkel Lund After the failure of a second of Kepler’s four reaction wheels, the mission was expertly re-purposed into the ecliptic plane K2 mission. Compared to the nominal Kepler mission, K2 will observe many nearby bright stars, providing the opportunity to apply asteroseismology to study the local solar neighbourhood. The bright targets provide powerful tests of stellar structure and evolution, because follow-up and complementary observations may be more readily obtained and combined with asteroseismology. Importantly, K2 allows us to study many interesting stellar clusters, which were only sparsely represented in the nominal Kepler mission, especially young clusters, such as the Hyades, the Pleiades, Praesepe/M44, and M67, in addition to the old globular cluster M4. I will in this talk present recent results obtained on solar-like oscillators observed during K2 Campaigns 1-5. T42 Asteroseismology of Red Giants in the Open Cluster M67 – Finally! Dennis Stello M67 is arguably one of the most studied open clusters in history. This continuing interest has been sparked by its near solar age and metallicity making it resemble the birth space of the Sun. With the prospects of applying seismic techniques, as successfully done for the Sun, recent decades also saw studies aimed at detecting solar-like oscillations in the cluster stars, but with limited success due to the extremely low amplitude oscillations. However, recent space missions have revolutionised our ability to perform asteroseismic inferences on cool stars. From the the unfortunate end to NASA's Kepler mission arose its successful ecliptic mission K2. Unlike previous missions, K2 can observe several interesting stellar clusters; and M67 is one of them. In this talk I will show hot of the press results on the asteroseismology of red giants in M67 observed by K2, from which I will demonstrate the potential of this beautiful data set, which is already showing interesting results among the red giants. T43 Understanding Mixing Processes in A and F Stars through Asteroseismology Victoria Antoci The A and F type stars occupy a region in the HRD where several physical processes occur: it is in the classical instability strip where the transition between deep and efficient to shallow convective envelopes takes place. This has an impact not only on pulsational stability but also on stellar evolution, activity and transport of angular momentum. In this talk I will highlight what we have learned about delta Scuti and gamma Doradus stars from Kepler and K2 observations and show how ensemble studies of these stars can contribute to our understanding of mixing processes such as atomic diffusion and rotation. I will further show that unlike what is generally accepted, the kappa mechanism is not the sole mechanism to excite oscillations in delta Scuti stars. Models using timedependent non-local convection treatment predict the turbulent convection in the hydrogen ionisation zone to coherently excite pulsations. Our results are consistent with observations and can also explain the large fraction of pulsating chemically peculiar Am stars. These stars are expected to be constant as due to the settling of He, this element is not sufficiently abundant in the He II zone for the kappa mechanism to drive pulsations. T44 The Dor Stars as Revealed by Kepler: A Key to Reveal Deep-Layer Rotation in A and F Stars Sébastien Salmon Rhita Ouazzani V. Antochi T. Bedding S. Murphy I. Roxburgh The Dor pulsating stars present high-order gravity modes, which make them important targets in the low-mass main-sequence region of the Hertzsprung-Russell diagram. Whilst we have only access to rotation in the envelope of the Sun, the g modes of Dor stars can in principle deliver us constraints on the deep layers close to their convective core. Yet, their pulsations remain hard to detect from the ground for their periods are close to one day. While CoRoT space mission first revealed very puzzling frequency spectra, the long and almost uninterrupted 4-year photometry from Kepler eventually shed a new light on them. It revealed regularities in the spectra, expected to bear signature of phycical processes in the shear layers close to the convective core. We present here our effort to derive exploitable seismic diagnosis for mid- to fast rotators among Dor stars. These latter are based on the spacing in period between modes of consecutive order. We systematicly explore a grid of Dor models presenting a broad range of stellar parameters and various physical prescriptions. With help of appropriate pulsation codes, we determine the possible degeneracy induced by various set of stellar parameters and explore how to derive the internal profile of rotation unequivocally. We then deliver a first theoretical interpretation of some Kepler Dor pulsation spectra. T45 Pulsating Star Research from Antarctica Merieme Chadid In this invited talk, we implement a new way to study the stellar oscillations, pulsations and their evolutionary properties with long uninterrupted and continuous precision observations over 150 days from the ground, and without the regular interruptions imposed by the earth rotation. PAIX–First Robotic Antarctica Polar Mission– gives a new insight to cope with unresolved stellar enigma and stellar oscillation challenges. The project is made of low cost commercial components, and achieves astrophysical measurement time-series of stellar physics fields, challenging photometry from space that shows large gaps in terms of flexibility during the observing runs, the choice of targets, the repair of failures and the inexorable high costs. PAIX has yet more advantages than space missions in observing in U BV RI bands and then collecting unprecedented simultaneous multicolor light curves of several targets. We describe the first polar robotized mission PAIX and the outcome of stellar physics from the heart of Antarctica during several polar nights. We briefly discuss our first results and perspectives on the pulsating stars and its evolution from Antarctica, Finally, we highlight the impact of PAIX on the stellar physics study and the remaining challenges to successfully accomplish the Universe explorations under extreme conditions. T46 Exposing White Dwarf Core Structures: Towards Observational Constraints on Nuclear Burning and Chemical Mixing of He-Core-Burning Phases Noemi Giammichele Stéphane Charpinet Gilles Fontaine Pierre Brassard We present our latest results obtained from asteroseismic analyses of four pulsating white dwarfs from the Kepler and Kepler 2 fields. Our seismic procedure using the forward method based on physically sound, static models, includes a new core parameterization leading us to reproduce the periods of these stars at the precision of the observations. These new fits outperform current state-of-the art standards by order of magnitudes. We precisely establish the internal structures of these stars and unravel the inner C/O stratification of their core. By studying their internal chemical compositions, and more precisely the C/O profiles, we can give better observational constraints on key processes such as nuclear burning, convection, and mixing, that shape this stratification over time. T47 Core Overshoot and Convection in delta Scuti and gamma Doradus Stars Catherine Lovekin Joyce Guzik The effects of rotation on pulsation in delta Scuti and gamma Doradus stars are poorly understood. Stars in this mass range span the transition from convective envelopes to convective cores, and realistic models of convection are thus a key part of understanding these stars. In this work, we use 2D asteroseismic modelling of 6 stars observed with the Kepler satellite to provide constraints on the age, mass, rotation rate, and convective core overshoot. We use Period04 to calculate the frequencies based on short cadence Kepler observations of six gamma Doradus and delta Scuti stars observed with Kepler. We then produce 2D rotating models of stars in the mass range 1.5 - 1.8 solar masses and use a 2D pulsation code to calculate the adiabatic pulsation frequencies. Comparison of these models with the pulsation frequencies of three stars observed with Kepler allowed us to place constraints on the age, mass, and rotation rate of these stars. All frequencies not identified as possible combinations were compared to theoretical frequencies calculated using 2D models including the effects of rotation and overshoot. The best fitting models for all six stars are slowly rotating at the best fitting age and have moderate convective core overshoot. In this work, we will discuss the results of the frequency extraction and fitting process. T48 Inferences for Stellar Opacities from Seismic Studies of the Hybrid Cep/SPB Pulsators Przemysław Walczak Jadwiga Daszyńska-Daszkiewicz Alexey Pamyatnykh The hybrid pulsators, that exhibit oscillations both in low order p/g modes and high order g modes, pose a challenge for pulsation theory and input physics because the range of their observed frequencies cannot be explained by any standard model. To overcome this shortcoming an increase of stellar opacities at certain depths has been invoked. It goes in line with the recent experimental results which give the higher opacities for iron and nickel. Although some achievements in seismic modelling with the modified opacities have been made, still too few hybrid pulsators have been studied in that way to draw some general conclusions and indicate a more clear direction. In order to explore comprehensively the problem of mode excitation, we investigate the four Cep/SPB stars: Eridani, 12 Lacertae, Pegasi and Lupi. By changing the mean opacity profile as a function of the depth, (log T), we try to account for both the observed frequency range and the values of the frequencies. In order to decrease the number of possible solutions, we make use of the non-adiabatic parameter f, whose value is very sensitive to the structure of the subphotospheric layers where pulsations are driven. Our preliminary results of this complex seismic modelling show the need for a significant modification of the opacity profile to meet all the required conditions. T49 Recent Progress in the Theoretical Modelling of Cepheids and RR Lyrae Stars Marcella Marconi Cepheids and RR Lyrae are among the most important primary distance indicators to calibrate the extragalactic distance ladder and excellent stellar population tracers, for Pop I and Pop II, respectively. In this presentation I first mention some recent theoretical studies of Cepheids and RR Lyrae obtained with different theoretical tools. Then I focus the attention on new results based on nonlinear convective pulsation models in the context of some international projects, including VMC@VISTA and the Gaia collaboration. The open problems for both Cepheids and RR Lyrae are briefly discussed together with some challenging future application. T50 On the Effect of Rotation on the Evolution and Pulsation Properties of Classical Cepheids Richard I. Anderson Hideyuki Saio Sylvia Ekström Georges Meynet Here we present the important effects of rotation on the pulsational and evolutionary properties of classical Cepheid variable stars. Rotation affects the luminosity, lifetime, structure, and chemical composition of massive and intermediate-mass stars. Classical Cepheids are intermediate-mass stars observed during an evolutionary phase that is particularly sensitive to such effects, thus providing stringent tests for stellar models. Moreover, Cepheids find versatile applications throughout astrophysics thanks to being standard candles as well as tools for dating stellar populations. We have carried out the first investigations into the effect of rotation on Cepheid properties based on Geneva stellar evolution models covering a wide range of masses, metallicities, and initial rotation rates. In this talk, we specifically present 1) mass-luminosity relations and how rotation explains the Cepheid mass discrepancy; 2) observables affected by rotational mixing; 3) results of a linear pulsation analysis; 4) period-age relations that depend on the rotational history of Cepheid progenitors. Time permitting, we shall also show that Cepheids obey a tight flux-weighted gravity-luminosity relation, which enables a distance estimate complementary to the famous Leavitt law. T51 Petersen Diagram Revolution Radoslaw Smolec Wojciech Dziembowski Paweł Moskalik et al. Over the recent years, the Petersen diagram for classical pulsators, Cepheids and RR Lyr stars, populated with a few hundreds of new multiperiodic variables. We will review our analyses of the OGLE data, which resulted in the significant extension of the known, and in the discovery of a few new and distinct forms of multiperiodic pulsation. The showcase includes not only radial mode pulsators, but also radial-non-radial pulsators and stars with significant modulation observed on top of the beat pulsation. First theoretical models explaining the new forms of stellar variability will be briefly discussed. These include e.g. excitation of strongly trapped non-radial modes of moderate degrees, both in Cepheids and in RR Lyr stars, or resonant excitation of beat pulsation accompanied with modulation. Some of the discovered variability types, e.g. with radial first overtone as the dominant pulsation mode, and with additional variability, which is too slow to be reconciled with the radial fundamental mode, still represent a challenge for stellar pulsation theory. T52 Pulsating Stars and the Extragalactic Distance Scale: The State of the Art Lucas Macri I will present recent results from the SH0ES project, which obtained homogeneous Cepheid photometry for ~3500 objects in V&I and ~2300 variables in H across 19 supernova hosts and 4 calibrators to determine the value of H0 with a total uncertainty of 2.4%. I will discuss the current 3.4 sigma "tension" between this local measurement and predictions of H0 based on CMB observations and an assumed cosmological model. I will review ongoing work by members of the SH0ES team on the absolute calibration of the Milky Way Period-Luminosity relations using a novel astrometric technique with the Hubble Space Telescope. Lastly, I will highlight recent results from another collaboration on the development of new statistical techniques to detect, classify and phase extragalactic Miras using noisy and sparsely-sampled observations. I will present preliminary Mira P-L relations at various wavelengths based on the application of these techniques to a survey of M33. T53 Araucaria Project: Pulsating Stars in Eclipsing Binary Systems Bogumił Pilecki Wolfgang Gieren Dariusz Graczyk Grzegorz Pietrzyński The use of Cepheids as distance indicators has a long history and has proven to be very useful. Our knowledge on these objects, however, was quite limited. The breakthrough came with the discovery of a classical Cepheid in an eclipsing binary system, which let us determine accurate physical parameters of the pulsating star, including its mass and radius. Since than several other pulsating stars in eclipsing binary systems were confirmed and analyzed by the Araucaria Project, including Type II Cepheids and an object of a new class - Binary Evolution Pulsator. These discoveries has also made possible the study of the projection factor determined directly from the modeling of light and radial velocity curves. I will give a short summary on the published results and present the current work and new challenges. T54 Towards a Renewed Galactic Cepheid Distance Scale from Gaia and Optical Interferometry Pierre Kervella Antoine Mérand Alexandre Gallenne Nicolas Nardetto We are assembling a comprehensive understanding of the pulsation and close environment of Cepheids. We developed a dedicated data analysis tool (SPIPS) that combines all available observables (angular diameters from interferometry, radial velocimetry, spectroscopic Teff, photometry) to derive the physical parameters of the star (effective temperature, presence of infrared excess, reddening,...) and the ratio distance/p-factor. Only a handful of trigonometric parallaxes of nearby Cepheids is currently available, mainly from HST's Fine Guidance Sensor. The first Tycho-Gaia data release in September 2016 will soon provide a sample of homogeneous distances to nearby Cepheids, but with a limited accuracy. Within a few years, the full Gaia data releases will solve the d/p degeneracy for a large number of stars and therefore allow us to address the major systematics of the SPIPS technique. The outcome will be a robust and accurate calibration of the Cepheid distance scale based on well-known Galactic Cepheids. Binary systems including Cepheids are important for two reasons: (1) they can provide us with highly precise independent distances and dynamical masses, (2) we can directly measure the photometric bias imposed on the Cepheid’s apparent flux by the companion. We are engaged in long term observing programs with the CHARA and VLTI interferometers to secure an extensive set of interferometric measurements of Cepheids, including angular diameters and binary orbits. I will present the first results and prospects of our observing program. T55 VEGA/CHARA and HARPS-N Observations of the Prototype Classical Cepheid Delta Cep N. Nardetto A. Merand E. Poretti D. Mourard M. Rainer J. Storm W. Gieren The B-W method is used to determine the distance of Cepheids and consists in combining the angular size variations of the star, as derived from infrared surface-brightness relations or interferometry, with its linear size variation, as deduced from visible spectroscopy using the projection factor. Observations of Delta Cep were secured with the VEGA/CHARA interferometer over the full pulsation cycle of the star. These visible interferometric data are consistent in first approximation with a quasi-hydrostatic model of pulsation surrounded by a static circumstellar environment (CSE) with a size of CSE = 8.9+/-3.0 mas and a relative flux contribution of fcse = 0.07 +/- 0.01. A model of visible nebula (a background source filling the field of view of the interferometer) with the same relative flux contribution is also consistent with our data at small spatial frequencies. In a second study, we analyze new HARPS-N spectra of Del Cep to measure its cycleaveraged atmospheric velocity gradient in order to better constrain the projection factor. We found that these new HARPS-N observations of Delta Cep are consistent with our decomposition of the projection factor. T56 Properties of Anomalous and Type II Cepheids in the SMC and LMC Monika I. Jurkovic Martin A. T. Groenewegen The Small Magellanic Cloud (SMC) and Large Magellanic Cloud (LMC) give us the possibility to study individual variable star types in a new way. Literature data provide us with photometric information about objects from the ultraviolet to the infra-red. Here we would like to show the results of our study of 247 anomalous and Type II Cepheids in the SMC and LMC detected by OGLE. Using the code: More of DUSTY (MoD), a modified version of the DUSTY radiative transfer code, and the assumption that our objects are at a known distance, luminosity and effective temperature were deteremined. From these data the HRD of these objects was compared with the theoretical models. The radius and masses of the examined stars was estimated, too. In the end, we have given the periodluminosity relations for the anomalous and Type II Cepheids. T57 Pulsating Stars in Centauri: Near-IR Properties and Period-Luminosity Relations Camila Navarrete Márcio Catelan Rodrigo Contreras Ramos Javier Alonso-García Centauri (NGC 5139) contains many variable stars of different types including Type II Cepheids, RR Lyrae and SX Phoenicis. We carried out on a deep, wide-field, near-infrared variability survey of Cen, using the VISTA telescope. We assembled an unprecedented homogeneous and complete NIR catalog of RR Lyrae and SX Phoenicis stars in the field of Cen. In this contribution, in addition to describing our catalog and presenting the derived light curves, we discuss the main characteristics of these variable stars, including mean magnitudes, amplitudes, and transformation relations between those parameters in the optical and JKs bands. Near-IR period-luminosity relations are also derived and used to determine an updated (pulsational) distance modulus for Cen, and compare with the distance modulus that we obtained using the Type II Cepheid populations in the cluster. For SX Phoenicis, we were able to derive, for the first time, empirical Period-Luminosity relations in both the J and Ks bands. T58 RR Lyrae Observations with Spitzer: Towards A High Precision Population II Cosmological Distance Scale Massimo Marengo Jillian Neeley Giuseppe Bono Vittorio Braga Massimo Dall'Ora The cosmological distance ladder, currently relying on Population I standard candles such as Local Group Cepheids, is at odds with findings from Cosmic Microwave Background Radiation experiments. Results from the Planck Collaboration reveal a ~3.0 sigma “tension” in the measured value of H0 that could be a strong indication of new physics in the current Lambda CDM models. To resolve this fundamental issue we are developing an independent route to the cosmological distance scale, based on infrared observations of Population II stellar indicators: RR Lyrae variables. We present here the first results from our Spitzer Space Telescope survey of RR Lyre in the field and Galactic globular clusters. We demonstrate that period-luminosity-metallicity relations for these stars at near(Braga et al. 2015) and mid-infrared (Neeley et al. 2015) wavelengths allow measuring distances with better than 2% accuracy. We show how our results, combined with upcoming instrumentation (e.g. JWST and WFIRST) capable to extract RR Lyre light curves within the entire Local Group of galaxies, will enable the calibration of an independent distance ladder anchored on these Population II pulsators, and the globular clusters where they are commonly found. POSTERS (Posters are listed in alphabetical order, according to the presenting author’s family name. The latter is shown in boldface type.) P1 Variable stars in the VVV globular clusters Javier Alonso-García Márcio Catelan Rodrigo Contreras Ramos István Dékány Dante Minniti The VVV survey has been observing the inner regions of the Milky Way during the last 6 years. There are 36 known Galactic globular clusters in the surveyed area. Most of them are poorly known, due to the elevated presence of gas and dust in their lines of sight. The VVV survey allows us not only to observe these globular clusters from their very centers out to their tidal radii and beyond at near-infrared wavelengths were the effect of extinction are highly diminished, but also to search for their variable stars thanks to its multi-epoch observations. In our contribution, we will show the first results of the analysis of the color magnitude diagrams of these clusters and the light-curves of their variable stars. We will explore what these analyses tell us about the physical parameters of these globular clusters and the extinction towards these objects. We will also discuss their Oosterhoff properties, and how they fit in the Oosterhoff dichotomy paradigma that seems to be present in our Galaxy. P2 Physical and pulsation characteristics of the CoRoT-observed Be star HD 171219 Learte Andrade Eduardo Janot-Pacheco Marcelo Emilio Yves Fremat We analyzed the Be Star HD 171219, observed with the CoRoT satellite during a 77.56 day run, in order to determine its physical and pulsation characteristics. High resolution ground-based spectroscopic observations with HARPS and SOPHI were also obtained during the month preceding the CoRoT observations. Tens of frequencies have been detected in the object compatible with non-radial g-modes, including a quintuplet centered around 1.113 c/d (12.88 µHz) identified as a pulsation of degree l~2. The star underwent at least 6 small outbursts during the CoRoT observations. The relative intensity of the main frequencies varied after each outburst suggesting that the stability of the star and the feeding of the envelope are linked to the pulsation regime. P3 Intermittent Mass Blowout of the Red Supergiant S Persei Yoshiharu Asaki Hiroshi Imai S-.H. Cho and ESTEMA team Red supergiants (RSGs) are in the near-final stage evolved from OB stars whose mass is higher than ten times of Sun’s. Although severe mass loss is often observed for RSGs, it is still unclear what can trigger the event and how the mass loss is connected to the RSG physical structures because it is said that RSGs have lower pulsation amplitudes. Here we report high spatial resolution images of single epoch three SiO maser transitions and one H2O maser transitions. Simultaneous observation of the masers claim that the SiO masers are spatially distributed in the central 100 AU region surrounded by the 400 AU H2O maser distribution. From the long period visual lightcurve, S Persei has repeated active and quenched pulsation phases by turn for several decades. It is considered that S Persei has had intermittent mass blowout repeatedly when the pulsation is active for several years. P4 Pulsational instabilities in blue and extreme prehorizontal branch stars Tiara Battich Marcelo M. Miller Bertolami Alejandro H. Córsico Leandro G. Althaus The -mechanism is a self-excitation mechanism of pulsations which acts on the regions inside the star where nuclear burning takes place. Due to the strong dependence of nuclear burning rates on temperature, the temperature perturbations induced by pulsations lead to an increase in the oscillation energy at the expense of the thermal energy of the star. Although the mechanism works wherever nuclear reactions are active, the pulsation amplitudes tend to be small in the high temperature layers where nuclear energy is generated so that the -mechanism is usually very weak. To the date there is not confirmation of -mechanism as the responsible of the excitation of pulsations of any star. However, it has been shown that -mechanism can excite pulsations in stellar models that undergo a hot helium-core flash, and the subsequent subflashes, before the star model settles into the stable helium core-burning phase. Moreover, it has been shown that the pulsations of LS IV-14o116, the only He-sdBV detected to the date, could be explained that way. In the present work we aim to extend the study of the mechanism effects on stellar models appropriate for stars on the blue and extreme prehorizontal branch, that undergo the helium sub-flashes that take place before the heliumcore burning phase. With this aim we perform detailed computations of non-adiabatic nonradial pulsations on such stellar models, adopting different values of metallicity, initial helium abundances and mass of the hydrogen envelope at the time of the main helium P5 Variable stars around selected open clusters in the VVV area Jura Borissova Nicolas Medina Radostin Kurtev Márcio Catelan We will present some resent results of variable stars investigation in the close vicinity of selected galactic open clusters projected in the VVV area. P6 A Review of Spectroscopic Frequencies and Modes in Doradus Stars Emily Brunsden K. R. Pollard P. L. Cottrell D. J. Wright This work presents the spectroscopic frequency analysis and mode identification of the class prototype, Doradus. In addition the results of 22 further stars studied using ground-based observations in both photometry and spectroscopy are reviewed. Of these stars two are binary stars and one is a hybrid Scuti - Doradus Star. Despite the small numbers of classifications, there are enough to identify some class features and compare these to pure frequency identifications such as those from Kepler. P7 Asteroseismology of the GW Virginis stars SDSS J0349 - 0059 and VV 47 Leila Magdalena Calcaferro Alejandro Hugo Córsico Leandro Gabriel Althaus GW Virginis stars are a well-studied class of nonradial g-mode pulsators. SDSS J03490059 and VV 47 are two PG 1159 star members of this class of variable stars. SDSS J0349-0059 is an interesting GW Vir star that shows a complete pulsation spectrum that includes rotational splitting of some of its frequencies. VV 47 is a pulsating PG 1159 star surrounded by a planetary nebula. This star is particularly interesting because it exhibits a rich and complex pulsation spectrum. We present an asteroseismological study of SDSS J0349-0059 and VV 47 aimed mainly at deriving their total mass on the basis of state-ofthe-art PG 1159 evolutionary models. We computed adiabatic nonradial g-mode pulsation periods for PG 1159 evolutionary models with stellar masses ranging from 0.515 to 0.741 Msun, that take into account the complete evolution of the progenitor stars. We first estimated a mean period spacing for both SDSS J0349-0059 and VV 47 and then constrained the stellar mass of these stars by comparing the observed period spacing with the asymptotic period spacing and with the average of the computed period spacings. We also employed the individual observed periods to search for a representative seismological model for each star. Finally, we estimated the rotation period of SDSS J0349-0059. P8 Pulsational stability of very hot, high-luminosity pre-white-dwarf stars evolved from low-metallicity progenitors María E. Camisassa Leila M. Calcaferro Alejandro H. Córsico Leandro G. Althaus Hiromoto Shibahashi White dwarf models evolved from low-metallicity progenitors have a thick hydrogen envelope, which makes hydrogen shell burning be the most important energy source. We investigate the pulsational stability of pre-white-dwarf models to see whether nonradial g-mode pulsations are triggered by hydrogen burning, with the aim of placing constraints on hydrogen shell burning in hot, high-luminosity white dwarfs. We extend the study by Maeda & Shibahashi (2014) who predicted that some low-order g modes are excited by the mechanism due to vigorous hydrogen shell burning in very hot and luminous prewhite dwarfs with hydrogen-rich envelopes derived from solar metallicity progenitors. P9 Whiting1: confirmation of its accretion by the Milky Way Julio A. Carballo-Bello Globular clusters have played an important role in the study of the processes that led to the formation of our Galaxy. Moreover, the dual Galactic globular cluster system is considered a manifestation of its hierarchical formation in the context of the LambdaCDM scenario. Wide-field imaging and spectroscopy, as the ones obtained for our project, are crucial tools to unveil the remnants of their progenitor dwarf galaxies, already assimilated by the Milky Way. In this poster, we present our results for Whiting1, where VLT/VIMOS MOS spectroscopy reveals the presence of a component of the Sagittarius tidal stream with a radial velocity – and distance – compatible with that of the globular cluster. Therefore, we conclude that Whiting1 was formed in the interior of the Sagittarius dSph and later accreted by the Milky Way. P10 A machine learned classifier for RR Lyrae in the VVV survey Felipe Elorrieta Susana Eyheramendy Andrés Jordán István Dékány Márcio Catelan Rodolfo Angeloni et al. Variable stars of RR Lyrae type are a prime tool with which to obtain distances to old stellar populations in the Milky Way. One of the main aims of the Vista Variables in the Via Lactea (VVV) near-infrared survey is to use them to map the structure of the Galactic Bulge. Owing to the large number of expected sources, this requires an automated mechanism for selecting RR Lyrae, and particularly those of the more easily recognized type ab (i.e., fundamental-mode pulsators), from the 106−107 variables expected in the VVV survey area. In this work we describe a supervised machine-learned classifier constructed for assigning a score to a Ks-band VVV light curve that indicates its likelihood of being ab-type RR Lyrae. We describe the key steps in the construction of the classifier, which were the choice of features, training set, selection of aperture, and family of classifiers. We find that the AdaBoost family of classifiers give consistently the best performance for our problem, and obtain a classifier based on the AdaBoost algorithm that achieves a harmonic mean between false positives and false negatives of ≈7% for typical VVV light-curve sets. This performance is estimated using cross-validation and through the comparison to two independent datasets that were classified by human experts. P11 Determining the core stratification in white dwarfs with asteroseismology Stephane Charpinet Noemi Giammichele Pierre Brassard Gilles Fontaine We present a novel approach to determine the C/O stratification in the core of pulsating white dwarfs using asteroseismology. This stratification, inherited from previous evolutionary phases, is one of the most uncertain aspect of white dwarf internal structure and more generally traces back to major shortcomings in our understanding of the helium core burning phases and beyond. In this contribution, we discuss the method and tests demonstrating the feasibility of this approach. P12 Catalogue of Variable Stars in Milky Way Globular Clusters Christine Clement I continue to work on updating the catalogue of variable stars in Galactic globular clusters (Clement et al. 2001, AJ, 122, 2587). It is posted on my website: www.astro.utoronto.ca/~cclement/read.html. The catalogue is arranged as a set of 149 files, one for each cluster. In my presentation, I will report on the current census of variable stars in Galactic globular clusters and show how it has changed over the years. P13 Large Binocular Telescope (LBT) view of Andromeda's dwarf spheroidal satellites F. Cusano A. Garofalo G. Clementini et al. Results are presented from deep time series observations of four dwarf spheroidal galaxies (dSphs) in the Andromeda (M31) complex, namely, And XIX, And XXI, And XXV and And XXVII, that we have resolved in stars using the Large Binocular Cameras of the Large Binocular Telescope (LBT). Thanks to the LBT observations we discovered a total of over 200 RR Lyrae stars and 20 Anomalous Cepheids in these M31 satellite galaxies. We have characterized the stellar populations and the spatial distributions of their resolved stars and found evidence for different stellar generations and processes of merging and disruption occurring in these M31 dSphs. We have also identified a candidate globular cluster in the center of And XXV, thus further increasing the observational evidence that globular clusters sitting in the core of dwarf galaxies are not an unusual feature both among the Milky Way and Andromeda's satellites. P14 Looking for the nature of Stellar Rotation in solartype stars Cristián Cortés Márcio Catelan José Renan De Medeiros Alejandra Recio-Blanco Rotation is one of the most important observable for our understanding of the evolution of stars. The CoRoT and Kepler space missions represent unique possibilities for the measurements of rotation period for statistically robust sample of stars, offering the necessary tools for the study of rotation and its role on stellar evolution. In this context, an essential step is the physical characterization of stars, in particular because the computation of reliable photometric period of from CoRoT and Kepler observations, would became a hard work without the help of the stellar parameters. This project is carrying out a complete analysis of the stellar rotation and momentum on a sample of solar-type stars (understood as main-sequence stars of spectral types FGK, and their more evolved counterparts) with different masses along the HR diagram. These stars were observed by the CoRoT satellite and also, will be observed by the Kepler satellite in the Kepler 2 (K2) mission. This analysis takes into account the combination of spectroscopic (groundbased) data and photometric observations from CoRoT and Kepler in order to pin down the stellar rotation. P15 Effective temperatures of Cepheids and the distance scale problem Alexey Rastorguev Andrey Dambis Marina Zabolotskikh Maria Ostashova Multi-phase measurements of the effective temperatures of 33 Milky Way Cepheids derived by Luck, Andrievsky, Kovtyukh et al. (2005-2008) from high-resolution spectra, are used to estimate directly their luminosities and distances. Cepheid's radii variations are calculated by the generalized L. Balona technique on the base of BV photometry and precise radial velocity measurements obtained with CORAVEL-type spectrometer during last 25 years. Cepheid PL relation is derived. P16 The evolved slowly pulsating B star 18 Peg: A testbed for upper main sequence stellar evolution Andreas Irrgang Peter De Cat Andrew Tkachenko Conny Aerts The predicted width of the upper main sequence in stellar evolution models depends on the empirical calibration of the convective overshooting parameter. Despite decades of discussions, its precise value is still unknown and further observational constraints are required to gauge it. Based on a photometric and preliminary asteroseismic analysis, Irrgang et al. (2016, A&A 591, L6) showed that the mid B-type giant 18 Peg is one of the most evolved members of the class of slowly pulsating B stars and, thus, bears tremendous potential to derive a tight lower limit for the width of the upper main sequence. In addition, 18 Peg turns out to be part of a single-lined spectroscopic binary system with an eccentric, more than 6-year orbit. However, to exploit the full potential of this star as benchmark object for stellar evolution theory, additional observations are required. In 2016, 18 Peg is approaching periastron and is hence in the orbital phase were the orbital velocity is changing fast. We therefore organised a follow-up campaign with the HERMES spectrograph attached to the 1.2-m Mercator telescope (Roque de Los Muchachos Observatory, La Palma, Canary Islands) to gather high-quality, high-resolution spectra appropriate for the fine-tuning of the orbit and for a detailed study of the main pulsation mode. In this poster, we will present updated results based on the new spectroscopic data. To complete the asteroseismic study, 18 Peg has been proposed as a target for the BRITE-constellation and will (probably) be observed for 27 days with the future space-mission TESS (to be launched in December 2017) to gather a complementary time-series of accurate photometry with a sufficiently long timebase to be able to study the expected low amplitude modes that have remained unobserved so far. P17 Between Cepheids and the Cosmos Nancy R. Evans Scott Engle Ed Guinan Hilding Neilson Massimo Marengo Lynn Matthews Moritz Guenther We have a number of tantalizing clues about material above the photosphere in classical Cepheids: Spitzer fluxes including an apparent resolved bow shock in Delta Cephei itself, H I 21 cm observations, and circumstellar shells from interferometric observations. The understanding of how these are related is patchy. There are a number of photospheric/ chromospheric diagnostics from HST UV spectra, confirming pulsation related activity immediately following minimum radius. The recent addition to these diagnostics is a brief X-ray increase at the surprising phase of maximum radius (when the photospheric UV lines are quiescent). The fast increase and subsequent fast decline suggest a shock phenomenon. The simplest characterization is a shock at about 2 stellar radii. The phase dependence ties this activity to pulsation. We will discuss the observational evidence and also plans for theoretical studies. This new clue is related to the questions of pulsation driven mass loss, and also the use of the IR in the Leavitt relation. P18 RR Lyrae stars as tracers of halo substructures Sonia Duffau Kathy Vivas Julio Carballo-Bello Camila Navarrete Márcio Catelan The study of the substructures present in the Galactic halo provides vital information about its origin and history, as well as constraints on the models of hierarchical galaxy formation and evolution. RR Lyrae stars have proven to be excellent tracers of halo substructures, due to the quality of the distances that can be derived from them, and the relatively straightforward methods that lead to their clean identification. In this poster I will present the techniques we have used and developed to unveil halo substructures using RR Lyrae stars. I will present a spectroscopic survey we are conducting using Catalina Real-time Transient Survey RR Lyrae targets in the southern sky, and show how our preliminary results connect (if they do) with structures discovered studying the Northern sky. P19 4-Years Interferometric Observations of Galactic Binary Cepheids: Update and Status Alexandre Gallenne Cepheid stars are powerful astrophysical laboratories providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. However, one of the most fundamental parameters, the mass, is a long-standing problem since decades because of the 10-20% difference between masses predicted from stellar evolution and pulsation models. Cepheids in binary system are the only tool to constrain models and progress on this mass discrepancy. Unfortunately, most of the companions are too close to the Cepheid (< 40 mas) to be observed with 8-meter class telescopes, and the highcontrast between the companions and the Cepheids makes the detection even more difficult. A technique able to reach high spatial resolution and high dynamic range is longbaseline interferometry (LBI). This talk aims at giving an update on our long-term interferometric program starting in 2012, which aims at detecting and measuring the astrometric positions of the companions. Using the VLTI/PIONIER and CHARA/MIRC instruments, we have now detected several components, and we start having a good orbital coverage for some of them. By combining interferometry and radial velocities, we can now derive all the orbital elements of the systems, and we will be soon able to measure the Cepheid masses. P20 A search for low-metallicity pulsating B stars Chris Engelbrecht We report on our latest results from a long-term UBVI survey of various fields in the LMC, with the aim of identifying and classifying pulsating B stars (i.e. Beta Cephei, SPB and hybrid pulsators) in the selected fields. P21 Machine Learning Techniques to Select Variable Stars José Alejandro García-Varela M. F. Pérez-Ortiz B. E. Sabogal A. J. Quiroz Long time variability surveys are producing a very large number of high quality light curves. Machine learning techniques and, particularly, statistical pattern recognition methods have proved to be quite useful in classification of variable stars. In the existing literature, quantities related to the magnitude density of the light curves and their Fourier coefficients are chosen as features. However, the calculation of Fourier coefficients is computationally expensive for large data sets. In order to perform a supervised classification, we propose and evaluate a set of six features, extracted from the magnitude density of the light curves, and used to train the automatic classification system. These features are based on robust descriptive statistics that can be calculated efficiently and do not need to be checked externally. We calculate the set of features on six types of OGLE-III variable stars and also on a set of Be Star Candidates reported in the literature. We evaluate its performance over the following state-of-the-art classifiers: K-nearest neighbors, classification trees, random forests, support vector machines, and gradient boosted trees. We use 10-fold cross-validation to estimate the recall and precision of these classifiers. We implement the classifiers in the R statistical computing environment, and validate them on a set of OGLE-IV light curves. P22 Infrared surface-brightness Bade-Wesselink analysis for selected Cepheids in the SMC Marek Gorski Wolfgang Gieren Bartlomiej Zgirski Piotr Konorski The basis of the Bade-Wesselink (BW) distnce measurement method is very well established, since it is a conceptually simple semi-geometrical method. Unfortunately, up to this day only one precise zeropoint calibration exist. We present the preliminary results of Infrared surface-brightness Bade-Wesselink analysis for 20 Cepheids in the Small Magellanic Cloud. Results are based on a precise radial velocity measurements and photometry in the infrared K and optical V bands. Presented measurements will allow to calibrate the zero point of this method and calculate the p-factor value, which will substantial improve the Bade-Wesselink distance estimation method. P23 The comparison of eclipsing binary and BaadeWesselink distances to OGLE-LMC-CEP-0227 Dariusz Graczyk The eclipsing binary cepheid CEP-0227 in the LMC is one of the prime targets of our program to understand fully systematics connected with Baade-Wesselink method of distance determination. Because of favorable geometrical configuration of this binary system we can determine very precisely physical parameters of both components: a short period fundamental Cepheid and a nonvariable ordinary red giant star. We measured distance to the system by two mostly independent ways: eclipsing binary method and Baade-Wesselink method applied to the pulsating components. By comparison of resulting distances we derive directly p-factor for this cepheid and we discuss this result in a wider context of p-factor “controversy”. P24 Infrared excess in Semi-Regular variables in the Magellanic Clouds Martin Groenewegen By systematically exploring the ViZier database we constructed the spectral energy distribution of about 100 LPVs that have I, (V-I) colours similar to Type-II Cepheids. We are interested in objects that have lightcurves similar to RV Tau objects but with periods longer than the formal limit used by the OGLE team in their selection of Type-II Cepheids. By fitting stellar photosphere models we determine luminosity and effective temperature, but of interest here are stars that might show an infrared excess. First results will be presented. P25 Stellar Observations Network Group (SONG) Frank Grundahl Victoria Antoci Mads F. Andersen Jørgen Christensen-Dalsgaard Hans Kjeldsen SONG is a Danish-led collaborative project set to design and build a global network of small telescopes that should specifically target the study of stars and planetary systems around stars. The objective was to develop a prototype of a new modern robotic telescope that would be inexpensive and efficient to run. The Hertzsprung SONG Telescope, i.e. the prototype of the SONG network, is located at the Observatorio del Teide (OT) of the Instituto de Astrofisica de Canarias (IAC) in Tenerife. The telescope is equipped with a high-resolution spectrograph aiming at precise radial velocity measurements and will have the capability of performing photometry using the Lucky Imaging technique. P26 RR Lyrae binary systems in the Galactic bulge Gergely Hajdu Márcio Catelan RR Lyrae stars are fundamental stellar probes of astrophysics: their easily identifiable, characteristic light curves, together with their well-known magnitudes, makes them excellent distance indicators. Furthermore, the properties of their pulsation (period, lightcurve amplitude and shape) are strongly dependent on the stellar interior, thus providing important constraints on the theory of the structure and evolution of old, low-mass stars. However, the theories of stellar pulsation and evolution both lack a crucial constraint: no direct mass measurements for any RR Lyrae star has ever been reported, which can be mainly attributed to the lack of reported RR Lyrae stars in binary systems. Lately, there has been a renewed interest in finding RR Lyrae binary systems by multiple independent groups. Among these, our search utilizing the decade-long photometry of the OGLE project towards the Galactic bulge has proven the most successful so far, with ~20 strong candidates found among the analysed ~2000 highest-quality light curves. In this poster, we describe our continued search and preliminary results for RR Lyrae binaries, utilizing the treasure trove of OGLE photometry. P27 Using APASS and 2GSS for Studying Variable Stars Arne A. Henden Stephen Levine Doug Welch Dirk Terrell The AAVSO Photometric All-Sky Survey (APASS) provides calibrated magnitudes in the range 7 < V < 17 for the entire sky, in BVugriZ_sY bandpasses. It has had 10 data releases, and is available at VizieR or from the AAVSO web site. While primarily designed for 0.02mag calibration, it provides photometry over a many-year baseline, and also has near daily cadence in the standard field regions on the equator. Likewise, the 2nd Generation Synoptic Survey (2GSS) is designed to be a follow-on to APASS, and will provide daily cadence in two passbands for the entire sky. While APASS has low cadence, it has wide spectral coverage, essential for disentangling many variable-star types. While 2GSS has daily cadence, it still pales in comparison with other transient surveys. However, it provides simultaneous 2-color photometry with finer resolution than even APASS. Combined, these two surveys enable variable-star studies in a different regime than any other existing survey. This paper will describe some methods of utilizing APASS and 2GSS, present some caveats, and suggest future directions for optimal all-sky surveys. P28 Fast template periodogram: application to targeted searches of periodic variable stars John Hoffmann Not yet available. P29 Newly identified young “dipper” stars in Upper Scorpius and Rho Ophiuchus star-forming regions Valentin D. Ivanov Young stars are typically irregular variables, and they change their brightness on different time scales, due to a number of mechanisms. The starts with disks tend to be more variable than the rest, and some of them show relatively short (usually up to 1-3 days) and sharp flux drops on the top of smooth light curves. We applied a combination of automated search and visual inspection of the K2 mission Campaign 2 data to identify 24 “dippers” in the Upper Scorpius and the Rho Ophiuchus star-forming regions, nearly doubling the existing sample. This behaviour is more common than previously tough, and extends down to the brown dwarf mass regimen. P30 The status and preliminary results of KMTNet Young-Beom Jeon The KMTNet (Korea Microlensing Telescope Network) was completed on October 2nd in 2015. There are three 1.6 m telescopes in Chile (CTIO), Australia (SSO) and South Africa (SAAO), respectively. The field of view of the CCD camera is 2 arc degree x 2 arc degree. We are monitoring and observing the bulge region for 24-hour continuous observation using the KMTNet telescopes. I will present the characteristics of CCD camera and telescope, and the status of observation programs. We are still developing CCD cameras and telescopes to accurate photometry. I will show also preliminary results for exoplanet search program, super nova search program, minor planet search program and extra galaxy observation program, etc., respectively. And we can obtain 24-hour huge continuous time-series data for many variable stars. P31 Precise distances to Local Group galaxies from infrared photometry of RR Lyrae stars Paulina Karczmarek In course of the Araucaria Project we determined true distance moduli from near-infrared photometry of RR Lyrae stars to five Local Group galaxies: LMC, SMC, Sculptor dSph, Carina dSph, and Fornax dSph. We applied period-luminosity-metallicity calibrations available in the literature to high-quality data obtained with SOFI/NTT and HAWKI/VLT instruments, located on La Silla and Paranal, Chile. Our data were collected, reduced and analyzed in consistent and homogeneous way, and yielded results with precision of 5% or better. This method is particularly suitable for galaxies and globular clusters that lack young standard candles, like Cepheids. P32 The connection between period spectra and constraints in white dwarf asteroseismology Agnes Kim White dwarfs are the end product of evolution for around 98% of the stars in our Galaxy. Buried in their interiors are the records of physical processes that take place during earlier stages in the life of the star. Not long after the discovery of the first pulsating white dwarf, the promise of asteroseismology to unveil the interior structure of white dwarfs and therefore help us constrain their prior evolution became apparent. In recent years, a well-established theory of non-radial oscillations, improved white dwarf models, year of expertise built up in the field of white dwarf asteroseismic fitting, and computing power have culminated in the asteroseismology finally delivering what it promised: a detailed map of the interior structure of white dwarfs. As always in science, new results raise new questions. We perform a number of numerical experiments to better understand the connection between a given set of periods varying in the number of periods and in the set of radial overtones and the quality of the constraints on interior structure one obtains from fitting these periods. P33 Little Bear's Pulsating Stars: Variable Star Census of dSph UMi Galaxy Karen Kinemuchi Katie Grabowski Charles Kuehn James Nemec Recent observations and a photometric search for variable stars in the Ursa Minor dwarf spheroidal galaxy (UMi dSph) are presented. Our observations were taken at Apache Point Observatory in 2014 and 2016 using the 0.5m ARCSAT telescope and the 3.5m telescope with the SPICam and ARCTIC instruments. Previously known RR Lyrae stars in our field of view of the UMi dSph are identified, and we also catalog new variable star candidates. Tentative classifications are given for some of the new variable stars. We have conducted period searches with the data collected with the ARCSAT telescope. With the 3.5m telescope, higher resolution time-series photometry was performed on two irregular variable stars, V80 and v3977, to clearly classify their variability. With our sample of RR Lyrae stars, we investigate any period and amplitude modulation from our datasets. Our ultimate goal is to create an updated catalog of variable stars in the UMi dSph and to compare the RR Lyrae stellar characteristics to other RR Lyrae stars found in the Local Group dSph galaxies. The comparisons can give us insights to the near-field cosmology of the Local Group. P34 Preliminary spectroscopic indication for Classical Cepheids in non-eclipsing binary Piotr Konorski Wolfgang Gieren Grzegorz Pietrzynski Bogumil Pilecki The Araucaria Project spectroscopic campaign on Classical Cepheids in Small Magellanic Cloud reveals a small number of objects with indication of additional variability superimposed on pulsation radial velocity curves. We present initial attempt to constrain orbital motion of presumably non-eclipsing binary systems, which - once confirmed would mark the first spectroscopic discovery of such systems in Magellanic Clouds. P35 Photometric Variability of L dwarfs Radostin Kurtev L brown dwarfs present tiny photometric variability on time-scales of hours. This rotationally modulated variability is due to magnetic phenomena and/or inhomogeneous cloud cover. However, inhomogeneous cloud cover alone can explain the observations. Here we present light curves, periods and amplitudes for two of our targets based on a very precise Js-band SOFI/NTT NIR photometry. Combining Js-band amplitudes with quasi-simultaneous SPITZER MIR amplitudes suggests that the regions with the thickest clouds also have the lowest effective temperature. P36 Faint Variable Stars observed with Kepler Catherine Lovekin Jasmin Tompkins We present preliminary analysis of approximately 10 variable stars observed with Kepler. The sample stars are faint (14th and 15th magnitude), and have temperatures greater than 8000 K. The stars were observed for up to three quarters (Q14-Q16) in long cadence mode. Frequencies were extracted with Period04, and 1-21 frequencies were detected in each quarter, with an average of 8 frequencies per quarter. Some variability is detected from quarter to quarter, while the dominant frequencies remain unchanged. We fit the frequencies using MESA models between 1.5 and 3 solar masses, and varied the core overshoot. Best fitting properties of each of these stars will be discussed. These stars have not previously been classified, and we will present our categorization of them here. P37 Rotation and magnetic activity of oscillating solarlike stars with the Kepler mission Savita Mathur For the last few decades the investigation of stellar magnetic activity has been conducted through spectroscopic and spectropolarimetric surveys. This led not only to the detection of magnetic cycles in other stars but also to variable and magnetic activity. For the Sun, the magnetic activity is described as the interaction between convection, rotation, and magnetic field. To study magnetic activity of solar-like stars we need to have the knowledge of the surface rotation period, the properties of magnetic activity, and the structure of the stars. This information can feed into dynamo models that are currently used to better understand the solar magnetic activity. The Kepler mission has been providing high-precision photometric data almost continuously for four years for around 200,000 stars. For a subset of solar-like stars, asteroseismic analyses have provided precise properties of the stars and their internal structure. Moreover with the photometric data we can measure surface rotation periods based on the presence of spots passing on the visible disk. This latter measurement can be done when a star is active meaning that we can also study changes in the magnetic activity of these stars by doing a timefrequency analysis. In this talk I will present the results obtained from the stellar dynamics studies of Kepler solar-like targets in terms of rotation periods, magnetic activity proxies and magnetic activity cycles detected. We can then combine this information with asteroseismic studies to have a broader picture of stellar magnetic activity. This work provided a large number of well-characterized solar-like stars that will put constraints on dynamo models to better understand the magnetic activity of our own Sun. P38 Variable stars in the northern Galactic plane from KISOGP Noriyuki Matsunaga KISOGP Team We have been conducting a large-scale survey of the northern plane using Kiso WideField Camera attached to Schmidt telescope at Kiso observatory. The KISOGP (KWFC Intensive Survey of the Galactic Plane) project have made 40-70 epoch observations in Iband of about 320 sq. degrees for over 3 years starting in 2012. The limiting magnitude is around 16.5 mag in I. In the data analysis so far, we detected a couple of thousands of variable stars including approximately 100 Cepheids and more than 700 Miras. Roughly 90% of them were not previously reported as variable stars, indicating that there are still many relatively bright variables to be found in the galactic plane. We'll present a preliminary map of the Cepheids and Miras together with results of spectroscopic followup observations for these objects. P39 Searching for distant RR Lyrae stars using the High cadence Transient Survey Gustavo Medina Toledo We present the results from an RR Lyrae search using data from the High cadence Transient Survey (HiTS). HiTS is a deep optical campaign carried out with the Dark Energy Camera (DECam) imager at the Blanco (4m) telescope on Cerro Tololo, Chile, aimed at detecting early supernovae explosions. However, the cadence of the survey and the strategy followed are well matched for RR Lyrae detection as well. Using data from 2014 we were able to detect new RR Lyrae stars out to at least 100 kpc from the Sun. In this poster we show the preliminary results of the search for RR Lyrae stars using HiTS' data from 2015, and discuss possible implications of these findings. P40 Spectro-Photo-Interferometry of Stellar Pulsation (SPIPS) Antoine Mérand We present our implementation of the parallax-of-pulsation which integrates all observables and physical modelling of the photosphere to get the best statistical precision and controlled biased. This method has been validated on well known stars (delta Cep and eta Aql), and used to estimate observationally the projection factor of the HST-FGS sample. Our future developments include application to the GAIA Cepheids and modelling of the spectrum. P41 VVV Maps of the Inner Milky Way Dante Minniti The VVV survey has been mapping the MW bulge and inner southern disk in the near infrared, covering ~540 sqdeg in the ZYJHKs filters. We present the current maps of the Milky Way bulge and disk obtained from VVV Survey observations. They include a color view, photometric completeness and photometric depth in all pass-bands, source density map, reddening maps, and photometric metallicity map. These maps can be used to obtain a global view of the bulge and study its constituent stellar populations. We also show our unique VVV collaboration model. P42 The additional-mode garden of RRab stars László Molnár Emese Plachy Péter Klagyivik Áron Juhász Róbert Szabó Space-based photometric missions revealed a surprising abundance of millimagnitudelevel additional modes in RR Lyrae stars. We now know that the majority of the fundamental- mode stars that experience Blazhko modulation also show one or more such modes, that can be ordered into four major categories. The most common features are period doubling, caused by the resonant ninth overtone, and the mode at ~0.6 P0 that may potentially correspond to the second overtone. In more rare cases (including the star RR Lyr itself), the additional modes can be identified with the first overtone, and finally some fall outside the above mentioned categories, so they are likely non-radial modes. Here we present a census of the additional modes from several hundred stars observed during the early K2 campaigns. P43 Insights on Milky Way and M31 halo formation mechanisms from RR Lyrae variables Matteo Monelli Giuliana Fiorentino Clara Martínez-Vázquez et al. Insights on Milky Way and M31 halo formation mechanisms from RR Lyrae variables. Short Summary: We will present a study the early formation history of the stellar halos of spiral galaxies, and the nature of their possible building blocks, based on the pulsational properties of the RR Lyrae (RRL) variable stars. In particular, we will show that the period and amplitude distributions of RRL stars show distinctive features in different stellar systems. This occurrence can be related to the parent stellar populations properties, such as the maximum metallicity attained by the RRL progenitors. In particular, High Amplitude Short Period (HASP) variables are common in the Milky Way (MW) and M31 halos, in globular clusters with [Fe/H] > -1.5 and in massive dwarfs, but not found in low metallicity globular clusters and faint dwarf galaxies. The comparison of the period distribution of RRL in the M31 and MW inner halos shows that the properties of RRL are similar in both, suggesting similar early formation histories. The HASP tail present in both indicates an important contribution to their formation from bright satellites. Additionally, MW halo RRL present a significant change in their period distribution when moving from the inner (R < 14 Kpc) to the outer (R > 14 Kpc) halo, suggesting formation from dissimilar progenitors or events. P44 Non-radial modes in AGB stars Josefina Montalban S. Bressan R. Suflaire P. Marigo The success of asteroseismology in characterising G-K giants has motivated the extension of the same techniques for stars after the central He burning and M-giants. The latter have been usually studied only as radial pulsators. The high density contrast between the central region and the envelope gives rise to serious numerical problems in the computation of non-radial modes of oscillations. In this poster we will present the theoretical results of this preliminary effort to compute and interpret the non-radial spectrum of stars from the Early AGB to the TP-AGB phases. P45 Multiperiodic RR Lyrae stars in the field of NGC6362 P. Moskalik R. Smolec, J. Kałużny, W. Pych, M. Różyczka, I. B. Thompson Population of known RR Lyrae-type stars in the globular cluster NGC6362 consists of 16 RRc and 18 RRab variables. We have analyzed 11 years of ground-based photometry of these objects, collected between 1999 and 2009. In 10 RRc stars (63% of the sample) nonradial modes with period ratio in the range of 0.608-0.631 to the dominant radial mode have been detected. This finding is yet another confirmation that excitation of such modes is very common in the RRc pulsators. Blazhko effect (long term amplitude and phase modulation) has been found in 3 RRc star (19% of the sample), in 1 of them the modulation is double-periodic. In case of RRab stars, no secondary modes have been detected. However, the Blazhko modulation is very common and affects ~70% of these variables. In two stars previously classified as RRab pulsators, V3 and V34, a week first radial overtone has been found. In both variables the resulting period ratio is non-typical, being close to 0.73, and the radial modes show long-term Blazhko-type modulation. Thus, V3 and V34 have to be re-classified as members of a newly defined group of anomalous RRd stars (Soszyński et al. 2016, submitted). P46 Variable Stars in massive star clusters in our Galaxy, as revealed by VVV Claudio Navarro Molina Jura Borissova Márcio Catelan et al. In this poster we will report some new results of search and analysis of the variable stars around two young and massive clusters in our Galaxy, namely Arches and Quintuplet. P47 Applying Survival Analysis on Cepheid PeriodLuminosity Relation at 70-Micron Chow-Choong Ngeow In this Poster, I apply the survival analysis to re-derive the Cepheid period-luminosity relation at 70-micron, at which about 2/3 of the currently available data only contains upper limits in flux. The survival analysis is a type of statistical technique to deal with data that has upper or lower limits – which is commonly seen in astronomy. I will also discuss preliminary results in the Poster. P48 New R Coronae Borealis and DY Persei Candidates in the SMC Fatemeh Nikzat Márcio Catelan R Coronae Borealis (RCB) stars are C-rich, H-deficient red supergiants that undergo dramatic dimming episodes at irregular intervals. The dimming episodes are believed to be caused by self-obscuration by dust, occurring as a consequence of mass loss events. The purpose of this contribution is to report on a new search for RCB stars in the Small Magellanic Cloud (SMC), carried out using V I light curves from the OGLE project. To detect candidates, the V I light curves of all SMC red variable stars were visually inspected, and compared against templates from the literature. New RCB candidates were detected in the process, which had previously been classified as semi-regular or Mira variables. Additionally, DY Persei candidates were also identified. Compared to their RCB counterparts, the DY Per stars tend to be cooler, have slower decline rates, and more symmetrical declines. If confirmed, these detections would lead to a significant increase in the number of known RCB + DY Per stars in the SMC. P49 Constraints on rotation of B-type pulsators from the nitrogen abundance Jakub Ostrowski Jadwiga Daszyńska-Daszkiewicz Rotation is one of the most important parameters that determine the evolution and the ultimate fate of a star. The effects of rotationally induced mixing modify the internal structure and, consequently, change conditions for excitation of stellar pulsations and the values of eigenfreqeuncies. Besides the difficulty in modeling the effects of rotation, there is also the problem in determining the rotation velocity from observations and usually only its projected value is known. In the presence of moderate-to-fast rotation, the abundance of surface nitrogen should increase during the course of evolution as an effect of rotational mixing processes. Here, we make an attempt to estimate the values of the rotational velocity and inclination angle for selected massive pulsators by comparing the measured nitrogen overabundances with the values predicted by evolutionary models computed with MESA code. P50 Eclipsing Binary Stars in the Era of Massive Surveys: First results and future prospects A. Papageorgiou M. Catelan Our thinking about eclipsing binary stars has undergone a tremendous change in the last decade. Eclipsing binary stars are one of nature’s best laboratories for determining the fundamental physical properties of stars and thus for testing the predictions of theoretical models. The largest such variable star surveys are the photometric multi-epoch Catalina Real-time Transient Survey (CRTS) and the VISTA Variables in the Via Lactea survey (VVV). These enormous surveys contain a large amount of photometric data and plenty of information about eclipsing binaries that wait to be extracted and exploited. We present a fully detailed eclipsing binary star catalog from CRTS with a) revised period determination using various techniques and b) phenomenological and physical parameters of selected eclipsing binary stars. Finally, we also present the progress of the analysis of VVV, including stellar variability investigation, future prospects in fundamental parameter determination, interesting examples from both surveys, as well as our first results so far. P51 Multi-site, multi-colour and space photometry of a Southern Delta Scuti star, 38 Eri Margit Paparo We present the preliminary results obtained on our large amount of data. We compare the ground-based data to the space data obtained by MOST The multi-site campaign and the MOST runs are divided by years, which gives possibility for checking the stability of the pulsation. Both Stromgren and Johnson photometry are available from the groundbased multi-site campaign. P52 Ultra-precise analysis of the light curves of CoRoT and Kepler delta Scuti stars Javier Pascual-Granado Rafael Garrido Haba Juan Carlos Suárez Yanes Jose Ramón Rodón Ortiz It is well known that the residuals of the multifrequency analysis of delta Scuti stars are correlated giving rise to challenging features such as a plateau (HD 50844, HD 50870, HD 49434, …) of non-resolved frequencies with amplitude higher than the expected noise level. Several hypotheses have been advanced to explain these features: effective convection, rotation, non-linear interactions, etc. We have recently demonstrated that in some cases the underlying function describing the light variations of delta Scuti stars has not the property of being analytic. The strong consequence of this result is that the Fourier expansion in which the harmonic analysis is based on, could be no justified. In order to know the extension of this phenomenon among delta Scuti stars, we have used photometric data from CoRoT seismofield and a large set of Kepler stars (short cadence). A discussion of the different hypotheses that could be on the origin of the non-analyticity follows the results. Work is in progress to overcome this inconsistency in the application of harmonic analysis. P53 Obtaining Accurate Radial Velocities for Cepheid Companions Using the STIS Echelles Charles Proffitt We use recent STIS echelle observations of hot companions of Cepheids to study the precision and repeatability of radial velocity measurements made using this instrument's E140H grating. The stability of the STIS optical bench, the optimal use of its calibration lamps, and the impact of aperture centering accuracy are discussed. We identify a number of ISM lines in the spectra of our targets that we use to quantify the repeatability of the absolute wavelength scale over time scales from minutes to years, and also discuss how the signal-to-noise and line widths of the stellar spectrum affect the precision that can be obtained in practice. The ultimate goal for this project is to determine the masses of the Cepheids. Any improvements in the accuracy of these companion velocities will translate directly into improved accuracy for these mass determinations. P54 Searching for Be Star Candidates within Large Databases Beatriz Eugenia Sabogal Martinez A. García-Varela Be stars are non-supergiant B stars that show or have shown Hydrogen emission lines in their spectra. These stars are also non-radial pulsators whose light curves show stochastic or quasi-periodic variations in different time scales. Long time surveys yield many high quality light curves among their subproducts, useful to identify candidate to Be stars that can also be confirmed by spectroscopic follow ups. We present in this work different techniques we have used to select new Be star candidates in the Milky Way and the Magellanic Clouds, from OGLE-II and ASAS databases. We also present the result of a new search for Be star candidates in the OGLE-IV Gaia South Ecliptic Pole Field. P55 Comparing the asteroseismic properties of pulsating extremly low mass pre-white dwarf stars and Delta Scuti stars Julieta Paz Sanchez Arias Pulsating Extremely Low Mass pre-white dwarfs, with masses between ~0.15Mo and ~0.30Mo, constitute a class of pulsating white dwarfs called pre-ELMV stars which exhibit radial-, p- and possibly g-mode pulsations with periods between 380 and 3500 sec, driven by the kappa mechanism operating in the zone of the second ionization of He. On the other hand, main sequence Delta Scuti stars, with masses between 1.22.5Mo, pulsate in low-order g and p modes in the range of [700:36300] sec, driven by the kappa mechanism operating in the HeII ionization zone. Interestingly enough, the pre-ELMV white dwarf and the Delta Scuti instability domains nearly overlap in the log Teff vs. log g diagram, leading to a degeneracy in the classification of the stars. In principle, asteroseismology can be employed to distinguish these very different kinds of stars. Motivated by this fact, we addressed an adiabatic asteroseismic comparison between these two families of pulsating stars, with the aim of providing tools for their correct classification. P56 Variability survey of young star forming region Saurabh Saurabh It is now well established that circumstellar discs are an integral part of star formation and are potential sites for planet formation Young star forming regions have significant number of pre-main-sequence (PMS) stars with circumstellar disc and are unique laboratories to study the evolution of discs of PMS stars. These stars are contracting towards MS or just reached the MS. Both WTTSs and CTTSs show variation in their brightness. These variations are found to occur at all wavelengths, from X-ray to infrared. Variability time- scale of TTSs ranges from a few minutes to years. The photometric variations are believed to originate from several mechanisms like rotation of a star with an asymmetrical distribution of cool spots, variable hot spots or obscuration by circumstellar dust The Herbig Ae/Be stars also show variability as they move across the instability region in the Hertzsprung–Russell diagram on their way to the MS. Several systematic studies of TTSs have been carried out which revealed different type of variabilities. It is now well known that some of them show periodic variability. In this poster, I will be presenting the results of our analyses related to the multi-epoch V-band photometry of various star forming regions taken with different telescopes to identify photometric variable stars in the region. This will help us to find any relation in the periods and amplitudes of the variable in optical wavelength with their evolution stage and mass. P57 The Blazhko RR Lyrae variables and phase modulation in binary systems Hiromoto Shibahashi The Blazhko phenomenon is the quasi-periodic amplitude and phase modulation seen in a fairly large fraction of RR Lyrae variables. The uninterrupted photometry with high precision from space missions revolutionised observations of these stars and revealed (i) a two-cycle amplitude modulation of the light curve, – the period doubling, (ii) a 2:9 resonance between a low-order mode and a high-order mode, and (iii) a presence of high-order multiplets. Nevertheless the Blazhko phenomenon still remains as a long-lived enigma to be explained. Frequency fine structures can also be seen in pulsating stars in binary systems. By carefully investigating the multiplets seen in RR Lyrae stars, I demonstrate that some of stars classified as Blazhko variables can be explained as binary systems and also show that some stars classified as binary systems are actually not binaries. P58 Finding Beat Cepheids in M33 and Their Use in Measuring the Metallicity Gradient Lawrence Short David Bersier The period ratio between the two different pulsation modes of beat Cepheids is directly affected by the metallicity of the star. This is backed up by observations of the Milky Way, LMC and SMC thus is used as an important constraint for stellar models. The aim of this project is to find all of the beat Cepheids in M33 and determine their metallicities by comparing them to Cepheids with known metallicity (Petersen diagram). This will allow us to accurately derive the metallicity gradient across M33. To achieve this we have images of M33 taken using the INT covering 13 nights over 19 months in addition to the CFHT variability survey conducted by Hartman et al (2006) covering 27 nights over 17 months giving a total of ~90 epochs. The two data sets need to be cross-calibrated then a period search will be applied in order to find all Cepheids in M33. I will present work on the calibration along with preliminary light curves of found Cepheids. P59 A 2-year orbital-period RR Lyrae Binary candidate Ádám Sódor Marek Skarka Jiri Liska Zsófia Bognár We discovered a new Kepler first-overtone RR Lyrae pulsator. The pulsation shows large, 0.1 d amplitude, systematic phase variations that can be interpreted as light travel-time effect caused by orbital motion in a binary system, superimposed on a linear pulsationperiod decrease. The assumed eccentric (e=0.47) orbit with the period of about 2 yr is the shortest among the non-eclipsing RR Lyrae binary candidates. The binary model gives a lowest estimate for the mass of the companion of 8.4 M_Sun, that places it among black hole candidates. Beside the first-overtone pulsation, numerous additional non-radial pulsation frequencies were also identified. We detected an ~47-d Blazhko-like irregular light-curve modulation. P60 TOUCAN. The VO gateway to stellar models Juan Carlos Suárez Carlos Rodrigo Enrique Solano José R. Rodón Virtual Observatory has gone beyond the realm of observations to connect scientists also with models. TOUCAN represents a step forward the on-line management and interoperability between stellar models collections. Currently devoted to asteroseismic models, this VO tool developed by the Spanish Virtual Observatory team, makes the life of scientists and work teams easier. P61 Distance scale calibration based on early-type binaries Mónica Taormina Grzegorz Pietrzyński Bogumil Pilecki Dariusz Graczyk Ian Thompson Wolfgang Gieren Our main goal is to establish a firm empirical calibration of the surface brightness vs. (V - K) color relation for early type stars based on high quality spectroscopic and infrared observations of early-type detached eclipsing systems in the LMC. Our calibration of this relation will allow distance determinations accurate to about 2.5 % to a single object located well beyond the Magellanic Clouds. This will let us calibrate other distance indicators, including the P-L relations for Cepheids. The first step of the project is to determine precise parameters for a sample of B-type systems in the LMC. Here I present the preliminary results from the analysis of light and radial velocity curves for selected objects, including measurement of the masses and radii. P62 Asteroseismic inferences from red giants in binaries and clusters Nathalie Themessl Oscillating red giants in eclipsing binaries and in open clusters provide tight constraints for testing theories of stellar structure and evolution. Thanks to the high-precision and long-term photometry obtained by the Kepler space mission, we are able to carry out comprehensive studies of red giants in a number of binary systems and open clusters. Through the oscillation spectra we deduce their stellar properties and evolutionary stages (asteroseismology), while at the same time the stellar properties can also be determined independently through the orbital analysis (binaries) or isochrones (clusters). In our study, we compare the derived stellar parameters from asteroseismology against independently determined stellar parameters to validate the asteroseismic methods. We also extract individual frequencies of oscillation modes that provide essential constraints for detailed stellar models and stellar ages. P63 Pulsation Models of O-rich and C-rich Long Period Variables Michele Trabucchi Paola Marigo Josefina Montalban Peter Wood Leo Girardi Low to intermediate mass stars experience the Asymptotic Giant Branch (AGB) during their late evolution, undergoing a number of complex and strongly interacting phenomena such as stellar oscillations, mass loss, dust formation, thermal pulses and dredge-up events. Their observed variability is currently attributed to radial pulsation in modes of low-radial orders. The study of stellar pulsation provides a way to probe the internal structure of such objects, and therefore to refine our understanding of late stellar evolution. However, updated theoretical pulsation models of such stars, especially of Cstars, have been missing from scientific literature for a few decades. We produced a new set of such models, intended to provide a broad coverage of the parameters space in terms of mass, luminosity, temperature and composition. Since the surface carbo-tooxygen ratio can be significantly altered by dredge-up events, we are especially interested in the effects of chemical composition, studied with up-to-date data for the metal mixture and detailed opacities for the outermost layers of such cool stars. We analyze how periods and growth rates depend upon global stellar parameters, and we compare our results with the OGLE-III observations of LPVs in the Magellanic Clouds. We aim to realize a large set of pulsation models to be made public in preparation for future observational surveys such as LSST. P64 Asteroseismology of the Kepler target KIC 9204718 Ceren Ulusoy Ivanka Stateva Iliani Iliev Burak Ulas We present the first preliminary results of a new investigation aimed to identify pulsation modes of KIC 9204718. The star is listed to be a binary system with a delta Scuti type pulsating component by Uytterhoeven et al. (2011). In order to determine the frequency content Kepler photometry is used. Spectroscopic and Photometric Observations are carried out with the 2 m RCC and 0.60 m Cassegrain Telescopes of the Bulgarian National Astronomical Observatory, Rozhen Bulgaria. The Ground-based multi-colour photometry is obtained to investigate modal behaviour of the star. High dispersion spectroscopic data is also used to derive the projected rotational velocity and atmospheric parameters. Tentative identifications of pulsation modes show that the component star shows Hybrid type pulsational characteristics. P65 Asteroseismology of the ZZ Ceti and DAZ white dwarf GD 133 J.N. Fu G. Vauclair J. Su et al. GD 133 is a DAZ white dwarf with an atmosphere polluted by heavy elements accreted from a debris disk formed by the disruption of rocky planetesimals whose orbits bring them at the white dwarf tidal radius. To reach such orbits implies the potential presence of a perturbing planet. GD 133 is a ZZ Ceti pulsator close to the blue edge of the instability strip. The presence of a planet could be revealed by the periodical modulation of the observed pulsation periods induced by the orbital motion of the white dwarf around the barycenter of the system. We started a multi-site photometric follow-up aimed at detecting the signature of this potential planet. As a preliminary result of this work in progress, we analyzed the data obtained during the 2011 campaign from which we derive the parameters of GD 133 from asteroseismology. P66 Important consequences of atomic diffusion inside main-sequence stars: opacities, extra-mixing, oscillations Morgan Deal Sylvie Vauclair Olivier Richard Atomic diffusion, including the effect of radiative accelerations on individual elements, leads to important variations of the chemical composition inside the stars. The accumulation of some important elements in specific layers leads to a local increase of the average opacity and to hydrodynamic instabilities that modify the internal stellar structure. We studied these effects in A-type stars using the Toulouse-Geneva Evolution Code (TGEC), where radiative accelerations are computed with the Single Valued Parameter (SVP) method. We took into account the induced double-diffusive convection with mixing coefficients deduced from three-dimensional (3D) simulations. We compared the resulting surface abundances with the observations. We discuss the consequences of these important physical processes for various stellar types. P67 The EREBOS project: Determining the influence of substellar objects on stellar evolution Maja Vuckovic Planets and brown dwarfs in close orbits around main sequence stars will inevitably interact with their stellar hosts once they ascend the red giant branch. The details and outcomes of these interactions are currently unclear. Recent discoveries of brown dwarfs and planets orbiting post-red giant branch hot subdwarf stars implies that the substellar objects are not only sufficient for ejecting the outer layers of a red giant’s atmosphere, but that they can also survive the engulfment phase. Thirty-six new eclipsing hot subdwarf binaries with cool, low-mass companions were discovered from light curves obtained by the OGLE project, tripling the number of known systems. Here we present the Eclipsing Reflection Effect Binaries from the OGLE Survey (EREBOS) project to determine the orbital velocities and atmospheric parameters of the sdB primaries and, ultimately, the companion masses. The final aim of this large project is to use this homogeneously-selected sample to derive the mass distribution of the companions and determine the minimum mass needed to strip off the red-giant envelope and survive the common envelope phase. P68 Stellar variability from Dome A, Antarctica Lingzhi Wang The Antarctic plateau is one of the best observing sites on the surface of the Earth thanks to its extremely cold, dry, stable and transparent atmosphere conditions. So far images have been collected from a 10-cm quad-telescope called the Chinese Small Telescope ARray (CSTAR) and the first of a trio of 50-cm Antarctic Survey Telescope (AST3-1). I will present the results of stellar variability from CSTAR and AST3-1, and the two targets' follow-up observations from Chile. P69 Distance to Small Magellanic Cloud from multiband P-L relations of classical Cepheids Piotr Wielgórski Grzegorz Pietrzyński Using OGLE optical and IRSF infrared photometry of Magellanic Clouds we derived extinction free P-L relations for classical cepheids in Large Magellanic Cloud and measured distance modulus of Small Magellanic Cloud in each band not corrected for extinction. From reddening law we also calculated extinction and E(B-V) ratio in each band. Relation between this ratio and distance modulus is linear and fitting straight line gives us distance modulus of SMC corrected for extinction and mean E(B-V) towards SMC. Because it is possible, that P-L relation changes its slope around 10 days we applied this method in two cases: for whole sample of cepheids in LMC and with periods of pulsation longer than 2.5 days in SMC, and for cepheids with periods longer than 10 days both in LMC and SMC. Our results are as follows: in first case 0.482+-0.005(stat) and 0.094+-0.004(stat) and in second case 0.471+-0.008(stat) and 0.103+-0.007(stat) for distance modulus and mean E(B-V) respectively. P70 The Araucaria Project. The Distance to the Sculptor Group Galaxy NGC 7793 from Near-Infrared Photometry of Cepheid Variables Bartlomiej Zgirski Paulina Karczmarek Marek Górski Grzegorz Pietrzyński We performed deep near-infrared J and K photometry of a field in the Sculptor Group spiral galaxy NGC 7793 using ESO VLT and HAWK-I instrument. We produced a sample of 14 Cepheids which locations and periods of pulsations were known from our previous paper on distance determination to this galaxy based on V and I bands. We determined mean J and K magnitudes based on measurements from two nights and produced periodluminosity relations for both filters. Using those near-infrared dependencies together with relations for bands V and I obtained before, we were able to obtain true distance modulus for the NGC 7793. We also calculated the mean reddening affecting our Cepheids.