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NC Astronomers’ Meeting
Saturday, 24 October 2016
Koury Auditorium, Guilford Technical Community College, Jamestown, NC
9:20 a.m.
Welcome & Announcements
If you pre-ordered lunch when you registered, please pay Dennis Hands in the lobby before the first presentation begins.
9:30 a.m.
Invited Speaker
David Charbonneau, Harvard University
The Compositions of Small Planets
The NASA Kepler Mission has demonstrated that planets larger than Earth yet smaller then
Neptune are common around Sun-like stars. Although Kepler determined the physical sizes
of hundreds of such worlds, we know virtually nothing about their masses and, by inference,
their compositions. For four years, we observed a carefully selected subset of these superEarths withe the HARPS-N instrument, an ultra-stable fiber-fed high-resolution spectrograph
built for this very purpose. I report on the constraints on the planetary compositions, and
address the transition from terrestrial planets, composed of rock and iron, to Neptune-like
worlds, which have accreted an envelope of primordial H/He gas. I will explain the essential
role of the NASA Transiting Exoplanet Survey Satellite (TESS), scheduled for launch in 2017.
David Charbonneau is a Professor of Astronomy at Harvard University. His research focuses on the discovery and characterization of
planets orbiting other stars, with the ultimate goal of identifying inhabited worlds. He was the first to observe a planet eclipse its parent
star; this method, known as transits, is now the means by which most planets outside the solar system have been identified. He also
developed the first methods which astronomers use to study the atmospheres of these distant worlds. He currently directs the MEarth
Project, which aims to find the first habitable exoplanet that can be searched for the chemical signatures of life, and the Aliens Earths
Initiative, an interdisciplinary collaboration that develops the tools with which to undertake that characterization. He was a member of
the NASA Kepler Mission, and he is a co-investigator in the upcoming NASA TESS Mission, scheduled for launch in 2017.
Dr. Charbonneau completed his PhD at Harvard in 2001. He spent 3 years as the Millikan Postdoctoral Fellow at Caltech before
returning to Harvard. He has received numerous awards for his research accomplishments, including the Waterman Award (the NSF's
top prize for a scientist under the age of 35), the NASA Medal for Exceptional Scientific Achievement, and he was named 2007
Scientist of the Year by Discover Magazine. In recognition of his commitment to teaching, he was recently named Harvard College
Professor.
10:30 a.m.
Break – visit the posters in the display area
11:15 a.m.
Contributed Oral Session I
1.1
Building a Small Geodesic Dome Planetarium
Jeff Regester (High Point University)
Two years ago three students and I built a 14-foot-diameter planetarium. The dome was constructed of PVC tubing and hubs, and
the hemispherical projection screen was made of heavy white canvas. The projection system consists of a half-dome security mirror
and Stellarium, an open-source sky simulator, which has a mode that morphs the image so that, once reflected off the mirror, the
projected image looks as it should. This presentation will outline the design and construction process, and highlight what I would do
differently if building another.
1.2
The Robo-AO KOI Survey: LGS-AO observations of every Kepler planetary candidate
Carl Ziegler (UNC-Chapel Hill),
The Kepler spacecraft has revolutionized exoplanet science, discovering thousands of transiting events around distant stars and
revealing that planets are ubiquitous in the galaxy. However, the thousands of planetary candidates found require ground-based
high-resolution follow-ups for planetary confirmation and characterization by detecting contaminating nearby stars within the same
photometric aperture. The telescope time required on a traditional AO system to complete this survey is enormous, with overheads
alone reaching more than 100 nights. Using the first fully autonomous LGS-AO system, Robo-AO achieves sub-minute overheads
and upwards of 200 observations a night, yielding a complete, homogeneous high-resolution survey of thousands of planetary
candidate systems. Beyond detecting false positives and correcting estimates of planetary property, this large sample allows a
search for broad-scale correlations between planetary systems and stellar multiplicity, giving insights into planetary formation and
evolution.
1.3
Faint Kepler Objects of Interest with Adaptive Optics and no Guidestar
Ward Howard (UNC-Chapel Hill),
Carl Ziegler (UNC-CH), Nicholas M. Law (UNC-CH), Christoph Baranec (Univ. of Hawai'i at Manoa), Reed Riddle (Caltech)
AO laser guide-star (LGS) systems perform several orders of atmospheric correction to stellar wavefronts to achieve best results. For
LGS, all high orders require a laser mounted to the telescope to fire into the sky, creating a fake star whose wavefront corrects
atmospheric defocusing to maintain image coherence. The lowest order, however, requires a moderately bright guide star in the FOV
to negate tip-tilt image movement, which restricts sky coverage. We propose a partial solution to this restriction by noting the
orthogonality of the orders-of-correction. Laser correction is independent of tip-tilt correction, motivating a survey to quantify
resolution improvement with laser-only AO. Robo-AO, the first robotic AO system, provides a unique test of laser-only correction, as
4 years of efficient robotic operation from 2012 through 2015 with the Palomar 60-inch telescope produced a database of tens-ofthousands of targets. Since the Robo-AO pipeline performs guide-star correction upon raw data after-the-fact, we may separate the
eff ects of each order to determine the resolution improvement of laser-only correction as being roughly half of all correction. To apply
this sky-coverage solution to high-resolution science goals, we implement laser-only correction to targets among the 10% faintest
candidate stars in the Kepler exoplanet database. These Kepler Objects of Interest (KOIs) necessitate high-resolution follow-up to
search for companion stars within 4.0” that could cause false-positive exoplanet transit signals or artificially small planet radii. We
search for companions in this faint KOI subsample using laser-only correction and compare the companion fraction of these faint
targets with the fraction of the overall KOI population.
1.4
Orbit of the Beta Aurigae Binary System from TCO Spectra
Kelin Kelcourse-Oquendo (UNC-Greensboro),
A. Miroshnichenko (UNCG), S. Danford (UNCG)
Beta Aurigae is a spectroscopic double-lined eclipsing binary system. It consists of two A-type dwarfs, with an orbital period of 3.96
days. We have obtained 25 spectra in a range from 4270-7890 Angstroms with an echelle spectrograph with the 0.81 meter
telescope of the Three College Observatory. We measured radial velocities of the H-alpha line and the 4481 A-MgII line, and we
assembled a radial velocity curve in a wide range of orbital phases. Comparison with previously published results shows a good
agreement with our data. The goals of this project were to increase the coverage of the phase curve, as well as check on the
wavelength calibration of the TCO spectra. In this talk, we briefly discuss the observations, data reduction procedure, and the main
results.
1.5
Polaris, the Nearest Cepheid, Spectroscopic Observations at the Three College Observatory
Anatoly Miroshnichenko (UNC-Greensboro)
Polaris (the North star) is the nearest pulsating star of the Cepheid type located at a distance of about 300 light years from the Sun.
The pulsations were first detected over a century ago and turned out to have variable amplitude and period. They stopped nearly 20
years ago but recently were detected again. Studying the pulsations permits determination of the star's evolutionary state with a high
precision. I will review history of Polaris' pulsations and show some results of spectroscopic observations taken at the Three College
Observatory last year.
1.5
Exoplanet Observations at an Urban Observatory
Joseph Holmes (Guilford College)
Following the success of wide-field surveys for planets in other star systems, small college observatories in urban environments are
able to play roles in exoplanet science research through follow up observations and analysis. Given the influx of data from these
surveys, many of the targets are poorly understood by the lack of routine analysis. Light pollution poses a major restriction on these
facilities' contributions to science and the telescopes are often used as solely an educational tool.
Utilizing the 16” Ritchey-Chretien at Guilford College I observed WASP-56b, a 0.577 Jupiter mass planet around a 11.484 host,
during the winter and spring months of 2016. The change in brightness of the host star during transit ranks amongst the most subtle
detections at the facility. Piedmont Triad International Airport lies two miles to the west and downtown Greensboro about three miles
east, producing a sky glow that washes out all but the brightest naked eye stars. The data analysis employed a differential
photometry technique, where a star which is not changing in brightness is compared to one which is, to eliminate most of the toxic
environmental effects and produce a transit light curve.
12:15 p.m.
Lunch – visit the posters in the display area
1:15 p.m. NCIDA Meeting
The North Carolina section of the International Dark Sky Association will meet in the auditorium during the lunch break. Join us to
discuss lighting issues of regional and state interest.
2:00 p.m.
1.1
Contributed Oral Session II
The Evryscope: The Data Analysis Pipeline for the First Gigapixel-Scale Telescope
Hank Corbett (UNC-Chapel Hill),
O. Fors (UNC-CH), N. Law (UNC-CH), D. del Ser Badia (Reial Acadèmia de Ciències i Arts de Barcelona and the Dept.
d'Astronomia i Meteorologia and Institut de Ciències del Cosmos), J. Ratzloff (UNC-Chapel Hill)
The Evryscope is an array of 24 small telescopes on a common mount, capable of observing the entire visible sky, down to g' ~ 16,
with a two-minute cadence. Each exposure covers 8000 square degrees and requires minimal readout time, providing 97%
continuous coverage of the night sky and the highest étendue of any currently operating project. The system's huge étendue and
rapid cadence enable exploration of a previously inaccessible parameter space of bright and fast transient events. In this talk, I will
discuss the ongoing project status with a focus on the development of our data reduction pipeline, which will provide years-long light
curves with 1%-level photometry for all bright and nearby stars
1.2
Spectroscopy of Pulsating White Dwarfs to Pursue Differential Seismology
Josh Fuchs (UNC-Chapel Hill),
Chris Clemens (UNC-CH), Bart Dunlap (UNC-Chapel Hill)
We have collected high signal-to-noise spectroscopy of over 120 pulsating white dwarfs (ZZ Cetis) using the SOAR Telescope. The
observed Balmer line profiles help determine the effective temperature and surface gravity of each star. We are paying special
attention to systematics in this process in hopes of producing the best relative effective temperature and surface gravity fits ever
achieved. We will present initial results showing that systematics do not prevent us from placing the stars in relative order. This
ordering will help probe the interior structure and composition of these stars.
1.3
A Virtual Survey of all Known Hot Subdwarfs with gPhoton: Searching for Pulsations
Thomas Macauley Boudreaux (High Point University),
Scott Fleming (STScI), Brad Barlow (HPU)
The study of pulsations in hot subdwarf stars, which follow non-standard evolutionary paths through the H-R diagram, allows for a
better understanding of the internal processes that drive such enigmatic objects. Before such pulsations can be studied, pulsating
targets must be identified. Here we present a search for short period pulsations in a large sample of hot subdwarfs using time-series
photometry generated by gPhoton, using raw UV data from GALEX.
1.4
A Newly-observed Bright Eclipsing Variable Star: b Persei (SAO 24531, HD 26961, HIP 20070)
Donald Collins (Warren Wilson College)
The bright (V = 4.6) ellipsoidal variable b Persei (not beta Persei) consists of a close non-eclipsing binary pair that orbit with ~1.5 day
period. The tidally distorted ellipsoidal shapes of the pair causes a small (0.06 V) sinusoidal variation with half the orbital period. This
system also contains a third star that orbits the binary pair every 702 days. The third star was only recently discovered to eclipse with
the inner close-binary pair in February 2013 by the AAVSO. Follow-up time-series campaigns in January 2015 and March 2016 have
confirmed the eclipsing nature of the system and have begun to allow more precise study of the nature of the three stars in the b
Persei system. These three observed eclipses consist of both the “primary” eclipse of the close binary pair by the third star and the
“secondary” eclipse in which the third star is eclipsed by the close binary pair. These eclipses are easily observed with digital
cameras or CCD detectors with a small telescopes (~50 mm aperture). The next eclipse is predicted in mid-December 2016.
1.5
Chemical Enrichment of the Early Solar System
Matthew Goodson (UNC-Chapel Hill)
Ian Luebbers (Macalester College), Fabian Heitsch, Christopher Frazer (UNC-Chapel Hill)
Meteoritic evidence indicates that numerous short-lived radioactive isotopes (SLRs) were present during Solar System formation
over 4.5 billion years ago. A primary source of these SLRs is stellar nucleosynthesis, suggesting the Solar system was exposed to a
supernova shortly before or during its formation. Yet results from hydrodynamical models of SLR injection into the proto-Solar cloud
or disk suggest that gas-phase mixing alone may not be efficient enough to reproduce the observed abundances. As an alternative,
we explore the injection of SLRs via dust grains as a way to overcome the mixing barrier. We numerically model the interaction of a
supernova remnant containing SLR-rich dust grains with a nearby molecular cloud. We confirm that dust grains of sufficient size (> 1
micron) decouple from the gas and penetrate into the cloud within 0.1 Myr, releasing SLRs and rapidly enriching the dense
(potentially star-forming) regions. These results suggest that SLR transport on dust grains is a viable mechanism to explain SLR
enrichment of the Solar System.
1.6
Cosmic-Ray Air Shower Modulation from Atmospheric Cooling in the Path of Totality of 21 August 2017
Enrique Gomez (Western Carolina University)
The total solar eclipse of 21 August 2017, visible in western North Carolina, offers an opportunity to study the atmospheric response
to cooling under the Moon’s shadow. We propose an experiment to follow up on a claim by Bhattacharyya et al. (1997) of an
observed drop of gamma-rays in the energy range of 0.3–3.0 MeV of up to 25% during the 24 October 1995 total solar eclipse at sea
level. The proposed explanation is that gamma-ray fluxes at sea level originating from the electron-photon components of cosmic-ray
air showers are modulated by the cooling of the atmosphere under the umbra. The cooling would reduce the height of the main
production layer of the nuclear component. Thus the shower produces fewer muons that would decay to electron-positron pairs, and
this would result in a reduction of in the subsequent gamma-rays. To test this theory, we propose to send stratospheric balloon
experiments through the path of totality to probe the cosmic-ray, air shower radiation count in the troposphere and locate the height
of the Pfotzer maximum. This experiment takes advantage of microcontroller sensor technology for data collection of cosmic-ray
counts, temperature and pressure, and we will present the results of some preliminary experiments. We will also show how to test
this model using the CORSIKA air shower simulation code.
3:30 p.m.
CAE Regional Teaching Exchange
CAE Regional Teaching Exchanges are designed to foster a sense of community amongst geographically linked current and future
Astro 101 instructors. The Center for Astronomy Education does not want astronomy instructors to feel isolated, or to have to wait to
attend (or re-attend) a CAE Tier I or Tier II workshop to continue their professional development. By using regional experts from the
broader CAE community, local teaching exchanges can be developed to allow instructors to develop connections between colleagues,
expand their instructional repertoire, and share expertise.
This year’s exchange will focus on Solar Eclipse Observing Activities for Intro Astronomy Students, but all topics are welcome.
Additionally, a Share-a-thon table will be set up for sharing copies of assignments, labs, education research, etc.
NCAM 2016 Display Presentations
Posters can be set up before the morning invited talk.
The display area is open for browsing throughout the meeting.
D1
The PARI 12 meter Radio Telescope
Don Cline, Tim Delisle, Colleen Lemmers (Pisgah Astronomical Research Institute)
The Pisgah Astronomical Research Institute has begun operation on its campus of a repurpose 12-m radio telescope. This instrument
was originally used for communications, but now has been upgraded for astronomical education and research. A new set of motors and
controllers have been installed, along with new software to drive the telescope and its receiver. The receiver is a new SpectraCyber
spectrometer, along with new amplifiers and horn operating at 1420 MHz. The telescope recorded first light on June 1, 2016 using its
1420 MHz receiver, and was used during the Summer undergraduate and high school programs at PARI. We will present detailed
specifications of the hardware and software, along with lessons learned in renovating a radio telescope. This radio telescope provides
PARI with ability for research capabilities at additional frequencies including 22.35 Ghz water masers.
D2
The Expansion of the Astronomical Photographic Data Archive at PARI
Donald Cline, Thurburn Barker (Pisgah Astronomical Research Institute), Michael Castelaz (Brevard College)
A diverse set of photometric, astrometric, spectral and surface brightness data exist on decades of photographic glass plates. The
Astronomical Photographic Data Archive (APDA) at the Pisgah Astronomical Research Institute (PARI) was established in November
2007 and is dedicated to the task of collecting, restoring, preserving and storing astronomical photographic data and PARI continues to
accept collections. APDA is also tasked with scanning each image and establishing a database of images that can be accessed via the
Internet by the global community of scientists, researchers and students. APDA is a new type of astronomical observatory – one that
harnesses analog data of the night sky taken for more than a century and making that data available in a digital format.
In 2016, APDA expanded from 50 collections with about 220,000 plates to more than 55 collections and more than 340,000 plates and
films. These account for more than 30% of all astronomical photographic data in the United States. The largest of the new acquisitions
are the astronomical photographic plates in the Yale University collection. We present details of the newly added collections and review
of other collections in APDA.
D3
The Galactic Distribution of Contact Binaries
Michael Castelaz (Brevard College), Leah Dorn (West Henderson High School), Abigail Breitfeld (Durham Academy),
Regan Mies (Saint John’s Preparatory School), and Tess Avery (St. Paul’s School)
The number of contact binaries in different galactic latitudes and longitudes show peak distributions in the number per square degree in
two latitudinal zones (-30° to -25° and +25° to +30°) and large fluctuations in longitude (Huang and Wade 1966, ApJ, 143, 146). The
relatively low number densities between the peak distributions of contact binaries could be due to obscuration by galactic extinction.
Using this argument of obscuration, we can infer similar galactic distributions of semi-detached and detached binaries as well.
However, neither semi-detached or detached binaries show galactic distributions similar to the contact binaries, and rather are
concentrated in the galactic plane as shown by Paczynski et al. (MNRAS, 368, 1311) in their paper on eclipsing binaries observed in
the All Sky Automated Survey catalog.
To understand the nature of the peak distributions of the contact binaries above and below the galactic plane, we use galactic structure
models constructed by Chang et al (2011, 2012) to compare the galactic distribution of contact binaries stars to galactic distribution of
semi-detached and detached binaries, as well as the general population of stars. Chang et al. constructed their model based on
2MASS J-KS colors. We use the 2MASS and Hipparcos databases to extract the J-KS colors, and derive photometric distances for the
binaries. We place the binaries within the galactic structure framework with this data.
D4
Spectroscopic Followup of Extreme Binaries
Padraig Clancy, Thomas Boudreaux (High Point University)
The Kepler 2 mission has provided light curves for many systems, some of which are indicative of having a dense primary star and a
less dense secondary star such as would be present in a A+WD or EL-CVn type system. Patterns indicative of ellipsoidal deformation
and Doppler boosting can be seen in the light curves of these systems. This indicates a very close orbit as well as very high orbital
velocities. We followed up Kepler 2 photometry with high resolution spectroscopy from CHIRON at the SMARTS 1.5 meter in order to
determine the system compositions. Here we present on two of these systems.
D5
The EREBOS Project: Studying the Effects of Substellar Companions on Stellar Evolution
Ryan Hegedus, Brad Barlow, Alan Vasquez Soto, Padraig Clancy (High Point University)
HW Vir systems are binary systems containing a hot subdwarf star and a smaller companion red dwarf star. Previously, there were only
15 known HW-Vir binaries until light curves from the OGLE Survey revealed 36 new such systems. The smaller, cooler companion in
each of these systems has survived engulfment by a nearby red giant star. Thus, analyzing the companion mass distribution of HW Vir
systems could reveal whether brown dwarfs or even planets can survive engulfment by a red giant. The EREBOS Project was started
to obtain follow-up observations of the new binaries discovered by OGLE. The ultimate goal of EREBOS is to find a lower mass limit for
these systems. Using the Goodman Spectrograph (SOAR 4m telescope) and the SMARTS 0.9m telescope, we were able to collect
time-series photometry and spectra for four of the EREBOS targets. We wrote photometry and spectral analysis code in Python to
extract light curves and orbital velocities. The data were then modeled with the software Binary Maker in order to obtain all stellar
parameters, most importantly the companion mass. Our initial results imply that brown dwarfs may be able to survive red giant
engulfment.
D6
There and Back Again?: The Disappearing Pulsations of CS 1246
Alan Vasquez, Brad Barlow (High Point University)
Hot subdwarf stars were once main sequence stars, like the sun, that deviated from normal stellar evolution due to binary interactions
and evolved into extreme horizontal branch stars. Several of these stars exhibit rapid pulsations driven by iron opacity instabilities. CS
1246 is a rapidly pulsating hot subdwarf discovered in 2009 that is dominated by a single 371 second pulsation. At the time of its
discovery, the pulsational amplitude was one of the largest known, making CS 1246 an ideal candidate for follow up studies.
Observations in 2013 implied that the pulsational amplitude had decreased significantly. Since then we have continued monitoring the
star using the robotic SKYNET telescopes in Chile, in order to further characterize any changes. Our recent observations show that the
pulsational amplitude has gone down by a factor of six: CS 1246 is barely a pulsator anymore. The decay in amplitude over time is
reminiscent of a damped harmonic oscillator. Here we present six years of photometry for CS 1246 and discuss possible scenarios that
might explain its interesting behavior.
D7
Searching for White Dwarf Variability Using gPhoton
Michael Tucker (Appalachian State University), Scott Fleming (STScI), Daniel Caton (Appalachian),
Bernie Shiao (CSRA), Chase Million (Million Concepts)
While interning with the Space Telescope Science Institute (STScI) in Baltimore, Maryland, I (MT) worked with Scott Fleming to conduct
a white dwarf survey in ultraviolet wavelengths. I continued that research at Appalachian State, working with Dr. Dan Caton. We utilized
a new software program, gPhoton, to retrieve and compile data for analysis Over 350 white dwarf stars from the McCook-Sion Catalog
were investigated for short- and long-term variations in the ultraviolet. Analytical procedures were developed using Python scripts to
plot the light curves. We inspected the light curves for variations caused by flares, pulsations, transiting exoplanets and binary/multi-star
systems.
D8
BVRI Photometric Study of the Short Period Solar Type Near-Contact W UMa Binary, FF Vulpeculae
Dan Caton (Appalachian State University), Ronald G. Samec, Ropafadzo Nyaude (Emmanuel College),
Walter Van Hamme (SARA)
High precision BVRcIc light curves of FF Vul were observed during the Fall, 2015 season at the Dark Sky Observatory 0.81-m reflector
of Appalachian State University, and the SARA North 0.91-m reflector at KPNO. It is an eclipsing binary with a period of only 0.444983
(2) d. This is the shortest period of our recently studied Pre Contact W UMa Binary (PCWB’s), V2421 Cyg, V1043 Cas, ZZ Eri, V500
Peg, and Mis V1287. Our Binary Maker fits and our Wilson-Devinney solution show that the binary is a near-contact, semidetached
binary, i.e., a V1010 Oph type configuration (the more massive component has filled its critical lobe while the secondary component is
under-filling). Five times of minimum light were calculated, 3 primary and 2 secondary eclipses from our present observations:
HJD I = 2457285.7262 ±0.0002, 2457306.6425 ±0.0002, 2457310.6469 ±0.0002
HJD II = 2457279.7222 ±0.0006, 2457280.6124 ±0.0017.
The following quadratic ephemerides was determined from all available times of minimum light:
JDHelMinI=2457310.6473±0.0007d + 0.4449758±0.0000002 X E -0.00000000006± 0.00000000001 X E2
The continuous 20 year period study reveals a period decrease in the orbital period at about the 6 sigma level. Our modeling shows a
near-equatorial hot spot on the following side of the secondary component. This is probably due to a matter transfer onto the secondary
component. The light curve has a large difference in primary and secondary amplitudes and the light curve solution gives a component
temperature difference of more than 1500 K. The solution shows a total secondary eclipse of 23 minutes duration. As expected in
binaries of this type, it has a cool spot region on its primary component.
D9
BVRI Photometric Study of the Totally Eclipsing Short Period Solar Type Near-Contact W UMa Binary NSVS 5066754
Dan Caton (Appalachian State University), Ronald G. Samec, Ropafadzo Nyaude (Emmanuel College),
Danny Faulkner (USC-Lancaster)
High precision BVRcIc light curves of NSVS 5066754 were observed on May 17-20, 2014 at Dark Sky Observatory in North Carolina
with the 0.81-m reflector of Appalachian State University. It is a solar type eclipsing binary (T1~5750 K) with a period of only 0.375132
(1) d. In fact, it appeared as one of the shortest period in Shaw’s list of near contact binaries. Therefore, we initially believed this to be a
pre-contact WUMa Binary (PCWB’s). However, the Binary Maker fits and our Wilson-Devinney solutions show that the binary could
have either a semi-detached or a contact binary configuration.
Five times of minimum light were calculated, for 3 primary and 2 secondary eclipses from our present observations:
HJD I = 2456794.6362±0.0019, 2456796.8898±0.0010, 2456797.6391±0.0003
HJD II = 2456794.8270±0.0003, 2456796.7027±0.0003.
In addition, observations at minima were introduced from archived All Sky Automated Survey Data along with the discovery ephemeris,
2451273.96475:
HJD I =2451390.17673 and 2451390.17704
The following decreasing quadratic ephemeris was determined from all available times of minimum light:
JDHelMinI=2456797.63848±0.00047d + 0.3747796± 0. 0000068 X E --0.0000000241± 0.0000000005X E2
We note that this result has a strong level of confidence.
Our contact solution, with a sum of square residuals = 0.49, gave a mass ratio of 0.50, and a component temperature difference of
~360 K, somewhat large for a contact binary. Two substantial cool spots were determined in this solution of 37º and 28º radius with a tfactor or 0.92 and 0.78 respectively. The fill-out is very shallow, ~6%.
The semi-detached solution (mode 4: V1010 Oph configuration, meaning the system is approaching first contact) is of poorer quality
with a sum of square residuals = 0.87. It has a mass ratio of 0.63, and a component temperature of ~460 K. The fill-outs are 100% and
97% for the primary and secondary components, respectively. Two spots were determined, one hot (t-factor of 1.16, 14 º radius,
colatitude 101 º) and one cool spot (t-factor of 0.94, 48º radius, colatitude 90º). The models in both cases are total eclipsing with high
inclinations in the 86-89º range, and a time of constant light is found in the secondary eclipse. Since the period study would indicate
that the binary may be coalescing, both solutions fit that scenario. The system may have just come into contact or is approaching
contact. The first model is more probable.
D10
Spectroscopic Chemical Abundance Determinations for Members of M67
Courtney McGahee (Appalachian State University), Constantine Deliyannis (Indiana University), Jeremy King
Clemson University)
Even though M67 is a well-studied open cluster, agreement on the overall metallicity of the cluster has not been reached. The goal of
this ongoing project is to report the spectroscopically determined chemical abundances of roughly 100 M67 members (including near
turnoff stars, subgiants, red giants, asymptotic giant branch stars, and horizontal branch stars) in an attempt to clarify the overall
chemical abundance trend for the cluster. Previously published M67 metallicity values and the current status of this project are
discussed here.
D11
SRAO: Bringing Robotic AO to the Southern Sky
Carl Ziegler (UNC-Chapel Hill), Nicholas Law (UNC-Chapel Hill), Andrei Tokovinin (CTIO)
The Southern Robotic Adaptive Optics (SRAO) instrument will bring the proven high-efficiency capabilities of Robo-AO to the SouthernHemisphere, providing the unique capability to image with high-angular-resolution thousands of targets per year across the entire sky.
Deployed on the modern 4.1m SOAR telescope located on Cerro Tololo, the NGS AO system will use an innovative dual-knife-edge
wavefront sensor, similar to a pyramid sensor, to enable guiding on targets down to V=16 with diffraction limited resolution in the NIR.
The dual-knife-edge wavefront sensor can be up to two orders of magnitude less costly than custom glass pyramids, with similar
wavefront error sensitivity and minimal chromatic aberrations. SRAO is capable of observing hundreds of targets a night through
automation, allowing confirmation and characterization of the large number of exoplanets produced by current and future missions.
D12
The Evryscope: The First Full-Sky Gigapixel-Scale Telescope
Nicholas M. Law, Jeff Ratzloff, Octavi Fors (UNC-Chapel Hill)
The Evryscope is a new type of telescope which covers the entire accessible sky in each exposure, and is sensitive to exoplanet
transits and other short timescale events not discernible for existing large-sky-area astronomical surveys. We present the design,
science case, and current status.
D13
Imaging the Galactic Center at Radio Wavelengths Using CASA
Vincent Hickl, Kristen Thompson (Davidson College)
The center of our Galaxy is known to be a very complex and dynamic environment which plays host to a number of interesting
structures and physical phenomena. The rotational center of our Galaxy is known to be coincident with a supermassive black hole
called Sgr A*, which is surrounded by a spiral thermal ionized hydrogen (HII) region called Sgr A West and a non-thermal shell-like
structure called Sgr A East. The objective of this project is to image the Sgr A complex using CASA, a new data reduction package
recently released by the National Radio Astronomy Observatory (NRAO). Specifically, we use observations made using the NRAO
Jansky VLA interferometer at 1667 MHz, which corresponds to an OH absorption line. Once the data has been reduced, we hope to
further analyze it to obtain precise magnetic field measurements for this region.
D14
How Wadesboro NC Became the Station of Choice for the Great American Eclipse of 1900
Tom English (Guilford Technical Community College)
The total eclipse of 1900 May 28 occurred as America was establishing itself, under the leadership of George Ellery Hale, as a world
leader in astrophysical research. Hale saw the eclipse as an opportunity to mobilize American astronomers in a coordinated effort to
study the Sun. He chose the small town of Wadesboro, NC, as his station for the eclipse, as did the Smithsonian’s S. P. Langley and
Princeton’s C.A. Young, both of whom were pioneers in solar astronomy from the generation before Hale. This presentation reviews the
expeditions gathered at Wadesboro and outlines the factors, decisions, and communications that led so many astronomers to choose
the site.
D15
Solar Eclipse Computer API: Planning Ahead for August 2017
Jennifer Lynn Bartlett (U. S. Naval Observatory), M. R. Chizek Frouard (USNO), M. V. Lesniak, III (USNO),
S. Bell (HMNAO)
With the total solar eclipse of 2017 August 21 over the continental United States approaching, the U.S. Naval Observatory (USNO) online Solar Eclipse Computer can now be accessed via an application programming interface (API). This flexible option returns local
circumstances for any solar eclipse in JavaScript Object Notation (JSON) that can be incorporated into third-party Web sites or
applications. For a given year, it can also produce a list of solar eclipses that can be used to build a more specific request for local
circumstances.
Over the course of a particular eclipse as viewed from a specific site, several events may be visible: the beginning and ending of the
eclipse (first and fourth contacts), the beginning and ending of totality (second and third contacts), the moment of maximum eclipse,
sunrise, or sunset. For each of these events, the USNO Solar Eclipse Computer reports the time, Sun’s altitude and azimuth, and the
event’s position and vertex angles. The computer also returns the duration of the total phase, the duration of the eclipse, the magnitude
of the eclipse, and the percent of the Sun obscured for a particular eclipse site.
On-line documentation for using the API-enabled Solar Eclipse Computer, including sample calls, is available
(http://aa.usno.navy.mil/data/docs/api.php). The same Web page also describes how to reach the Complete Sun and Moon Data for
One Day, Phases of the Moon, Day and Night Across the Earth, Apparent Disk of a Solar System Object, Dates of Ash Wednesday and
Easter Sunday, Dates of Islamic New Year and Ramadân, and First Day of Passover data services using API calls.
For those who prefer using a traditional data input form, local circumstances can still be requested that way at
http://aa.usno.navy.mil/data/docs/SolarEclipses.php.
In addition, the 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) consolidates all of
the USNO resources for this event, including a Google Map view of the eclipse track designed by Her Majesty’s Nautical Almanac
Office (HMNAO). Looking further ahead, a 2024 April 8 Solar Eclipse Resource page
(http://aa.usno.navy.mil/data/docs/Eclipse2024.php) is also available.
D16
Observing the 2017 Total Solar Eclipse from the Pisgah Astronomical Research Institute (PARI)
Sean Kirwan (Guilford College), Don Cline, Mark Krochmal (PARI)
The Pisgah Astronomical Research Institute (PARI) is located directly under the path of totality of next year’s solar eclipse and
possesses two 26m radio telescopes capable of interferometry at simultaneously at 2.3 GHz and 8.4 GHZ. PARI is preparing these
radio telescopes for use by the astronomical community to observe solar eclipse. We will present the status of PARI’s radio telescopes
and information on access for the eclipse. We will also present the status and availability of several optical telescopes.
D17
The D'Orbigny Angrite: a Pristine Relict from the Early Solar System
Anthony Love (Appalachian State University), J. Sinclair (PARI), J. D. Cline (PARI)
The 16.5kg D’Orbigny Angrite is an unshocked, unaltered basaltic meteorite that provides evidence for the sequence and chronology of
early solar system events such as planetary differentiation. The unaltered mineralogy of the D’Orbigny angrite allows for high precision
Pb-Pb dating which also allows it to serve as a reference point for relative timescales based on the 26Al-26Mg and 53Mn-53Cr isotopic
dating systems. The ancient 4.654Ga age and paleomagnetic signatures of D’Orbigny record some of the earliest evidence for
planetary differentiation and core formation. The unshocked nature of D’Orbigny and other angrites implies it originated on a body that
escaped the effects of the late-heavy bombardment or is size allowed it to be unaffected by this event.
Special Meteorite Display
John Sinclair, Curator of Meteorites, PARI
Support NCAM!
NCAM Registration will always be free, but there are event-related costs. If you would like to support our event, please consider
donating to the Jo Cline Memorial Astronomy Lecture Endowment Fund. This endowment, established by Don Cline in his wife’s
memory, generates funds to help bring our featured speaker to GTCC for the annual fall public lecture and NCAM presentation. Our
goal is to raise $50,000 for the endowment, and Don Cline will match, dollar for dollar, contributions made to this fund until our goal is
reached.
Please consider honoring Jo’s memory by contributing to the fund – Visit http://observatory.gtcc.edu/jo-cline-memorial-endowment/ to
make your donation.