Ages of young stars
... Although possible in only a few clusters, the LDB method is well-placed to calibrate other age estimation techniques used in those same clusters. Its usefulness in estimating ages for individual stars is limited; the detection of (undepleted) Li in a low-mass star at a known distance and luminosity, ...
... Although possible in only a few clusters, the LDB method is well-placed to calibrate other age estimation techniques used in those same clusters. Its usefulness in estimating ages for individual stars is limited; the detection of (undepleted) Li in a low-mass star at a known distance and luminosity, ...
THE ORION NEBULA AND ITS ASSOCIATED POPULATION C. R. O
... Heliocentric velocities will be used throughout this review, these values being 18.1 km s−1 more positive than M 42 velocities in the Local Standard of Rest. A complete PI model of a freely expanding blister nebula would incorporate both the effects of the heating and cooling processes arising from ...
... Heliocentric velocities will be used throughout this review, these values being 18.1 km s−1 more positive than M 42 velocities in the Local Standard of Rest. A complete PI model of a freely expanding blister nebula would incorporate both the effects of the heating and cooling processes arising from ...
Ages of Young Stars
... convective overshoot. Columns 2-4 list the apparent I magnitude of the LDB, the published LDB age and the source paper. Columns 5 and 6 give a bolometric magnitude and LDB age that have been homogeneously reevaluated using the locations of the LDB from the original papers, the evolutionary models of ...
... convective overshoot. Columns 2-4 list the apparent I magnitude of the LDB, the published LDB age and the source paper. Columns 5 and 6 give a bolometric magnitude and LDB age that have been homogeneously reevaluated using the locations of the LDB from the original papers, the evolutionary models of ...
The formation of spiral galaxies - Case Western Reserve University
... discussed in detail below. Of the five remaining galaxies, one is NGC 6946. This galaxy is rather face-on, and the resulting mass model is sensitive to debatable choices for the inclination. We therefore omit it from consideration. Four galaxies, NGC 925, NGC 2366, NGC 2976, and IC 2574, cannot be f ...
... discussed in detail below. Of the five remaining galaxies, one is NGC 6946. This galaxy is rather face-on, and the resulting mass model is sensitive to debatable choices for the inclination. We therefore omit it from consideration. Four galaxies, NGC 925, NGC 2366, NGC 2976, and IC 2574, cannot be f ...
They might be giants: luminosity class, planet frequency, and planet
... M dwarfs (Henry et al. 1994; Chabrier 2003; Reid et al. ...
... M dwarfs (Henry et al. 1994; Chabrier 2003; Reid et al. ...
they might be giants: luminosity class, planet occurrence, and planet
... occurrence is inversely related to planet mass or radius, with “super-Earths” outnumbering Jupiter-size planets by more than an order of magnitude. Around solar-type stars, the presence of giant planets is strongly correlated with super-solar metallicity (Gonzalez 1997; Santos et al. 2004; Fischer & ...
... occurrence is inversely related to planet mass or radius, with “super-Earths” outnumbering Jupiter-size planets by more than an order of magnitude. Around solar-type stars, the presence of giant planets is strongly correlated with super-solar metallicity (Gonzalez 1997; Santos et al. 2004; Fischer & ...
Searching for Planets During Predicted Mesolensing Events: II
... probability of an event occurring is very low. In addition, detection can be made challenging through the “dazzling by the light of the much nearer star”, the lens. Einstein’s doubts have not deterred astronomers, with their familiarity of the universe of possible lenses and background sources, from ...
... probability of an event occurring is very low. In addition, detection can be made challenging through the “dazzling by the light of the much nearer star”, the lens. Einstein’s doubts have not deterred astronomers, with their familiarity of the universe of possible lenses and background sources, from ...
THE STAR FORMATION AND NUCLEAR ACCRETION HISTORIES OF NORMAL GALAXIES
... spectroscopic signatures of AGNs, both obvious broadlined systems and those with emission-line ratios characteristic of Type II optical AGNs. We also carried out a principal component analysis of the optical spectra (e.g., Formiggini & Brosch 2004, Ferreras et al. 2006). In our analysis, the level o ...
... spectroscopic signatures of AGNs, both obvious broadlined systems and those with emission-line ratios characteristic of Type II optical AGNs. We also carried out a principal component analysis of the optical spectra (e.g., Formiggini & Brosch 2004, Ferreras et al. 2006). In our analysis, the level o ...
Galactic astroarchaeology: reconstructing the bulge history by
... perform a detailed elemental abundance analysis of dwarf stars in the Galactic bulge, based on high-resolution spectra that were obtained while the stars were optically magnified during gravitational microlensing events; Alves-Brito et al. (2010) use highresolution optical spectra of 25 bulge giants ...
... perform a detailed elemental abundance analysis of dwarf stars in the Galactic bulge, based on high-resolution spectra that were obtained while the stars were optically magnified during gravitational microlensing events; Alves-Brito et al. (2010) use highresolution optical spectra of 25 bulge giants ...
the harps-terra project. i. description of the algorithms, performance
... velocity Re-analysis Application. HARPS-TERRA handles the full process of unpacking the HARPS-ESO archive files, generation of a high-S/N template, and obtaining the final RV measurement in a single command line call. This software is custom made, fully coded in Java, and can run on any machine supp ...
... velocity Re-analysis Application. HARPS-TERRA handles the full process of unpacking the HARPS-ESO archive files, generation of a high-S/N template, and obtaining the final RV measurement in a single command line call. This software is custom made, fully coded in Java, and can run on any machine supp ...
Post-starburst galaxies: more than just an interesting curiosity
... From the VIMOS VLT DEEP Survey (VVDS) we select a sample of 16 galaxies with spectra which identify them as having recently undergone a strong starburst and subsequent fast quenching of star formation. These post-starburst galaxies lie in the redshift range 0.5 < z < 1.0 with masses > 109.75 M⊙ . Th ...
... From the VIMOS VLT DEEP Survey (VVDS) we select a sample of 16 galaxies with spectra which identify them as having recently undergone a strong starburst and subsequent fast quenching of star formation. These post-starburst galaxies lie in the redshift range 0.5 < z < 1.0 with masses > 109.75 M⊙ . Th ...
Possible structure in the GRB sky distribution at redshift two
... that the regions near the ecliptic poles (|β| ≥ 45◦ , where β is the ecliptic latitude) have been observed roughly 1.83 times more frequently than the region surrounding the ecliptic equator. Extinction due to dust from the Milky Way disk causes another angularly-dependent sampling bias. GRBs includ ...
... that the regions near the ecliptic poles (|β| ≥ 45◦ , where β is the ecliptic latitude) have been observed roughly 1.83 times more frequently than the region surrounding the ecliptic equator. Extinction due to dust from the Milky Way disk causes another angularly-dependent sampling bias. GRBs includ ...
The Star Cluster Population of M51: II. Age distribution and relations
... HST images and were recovered with exactly the same routines as used to find the real sources. A very important criterion is that objects should be 5 times above the standard deviation of the background. The value for σ should be the same as when real sources are found. The magnitude of the added so ...
... HST images and were recovered with exactly the same routines as used to find the real sources. A very important criterion is that objects should be 5 times above the standard deviation of the background. The value for σ should be the same as when real sources are found. The magnitude of the added so ...
The quest for the size of the universe in early relativistic cosmology
... path, now in the new framework of relativistic cosmology, of directly estimating R by using several astronomical objects, which, by their intention, played the role of distance indicators. Going beyond Einstein’s first attempt, these authors used either observations of stars, or assumptions on the m ...
... path, now in the new framework of relativistic cosmology, of directly estimating R by using several astronomical objects, which, by their intention, played the role of distance indicators. Going beyond Einstein’s first attempt, these authors used either observations of stars, or assumptions on the m ...
Planetary detection limits taking into account stellar noise
... In this paper, we present simulations exploring new measurement strategies allowing us to average granulation phenomena and oscillation modes at the same time. The detection limits for different strategies are derived, pointing out in particular a strategy that efficiently optimizes detection ability a ...
... In this paper, we present simulations exploring new measurement strategies allowing us to average granulation phenomena and oscillation modes at the same time. The detection limits for different strategies are derived, pointing out in particular a strategy that efficiently optimizes detection ability a ...
Cluster formation in molecular clouds – I. Stellar populations, star
... so that monolithic collapse to form a cluster does not occur. The observations of the Orion cloud suggest that subclustering occurs across large regions of the cloud (Megeath et al. 2012) so that the formation of a cluster would involve the eventual merger of a significant number of subclusters. The ...
... so that monolithic collapse to form a cluster does not occur. The observations of the Orion cloud suggest that subclustering occurs across large regions of the cloud (Megeath et al. 2012) so that the formation of a cluster would involve the eventual merger of a significant number of subclusters. The ...
Fast Optical Transients - Harvard-Smithsonian Center for Astrophysics
... chain, allowing for incomplete gamma-ray line is a model for the decline phase based on the instantaneous energy deposition events from the peak days prior to V-band maximum and then trapping. Dotted lines indicate the epochs of our early spectra. decline rapidly, consistent with our inferred time o ...
... chain, allowing for incomplete gamma-ray line is a model for the decline phase based on the instantaneous energy deposition events from the peak days prior to V-band maximum and then trapping. Dotted lines indicate the epochs of our early spectra. decline rapidly, consistent with our inferred time o ...
Classical Oe Stars in the Field of the Small Magellanic Cloud
... The study with the largest sample to date is by Negueruela et al. (2004), who took new spectra of all previously identified Oe, emission-line O, and peculiar O stars in the Milky Way (MW) visible from La Palma Observatory. O stars have stronger winds than B stars, so the frequency of Oe relative to ...
... The study with the largest sample to date is by Negueruela et al. (2004), who took new spectra of all previously identified Oe, emission-line O, and peculiar O stars in the Milky Way (MW) visible from La Palma Observatory. O stars have stronger winds than B stars, so the frequency of Oe relative to ...
EVIDENCE FOR IMF VARIATIONS WITH GALACTIC ENVIRONMENT
... large stellar mass range over which to measure the IMF (0.08 – 7 M⊙ , e.g., Moraux et al. 2004), but are more metal-rich than the UFDs. At metallicities less than [Fe/H] < −1, HST studies of Galactic globular clusters probe the IMF down to main sequence masses between 0.2 − 0.7 M⊙ (Paust et al. 2010 ...
... large stellar mass range over which to measure the IMF (0.08 – 7 M⊙ , e.g., Moraux et al. 2004), but are more metal-rich than the UFDs. At metallicities less than [Fe/H] < −1, HST studies of Galactic globular clusters probe the IMF down to main sequence masses between 0.2 − 0.7 M⊙ (Paust et al. 2010 ...
Measuring Reddening with SDSS Stellar Spectra and Recalibrating
... These runs observe regions of sky that are long in right ascension and narrow in declination. Each run is composed of observations from six camcols: the six sets of five CCDs (one for each of the photometric bands) that fill the SDSS focal plane. The SDSS photometry is used to select targets for fol ...
... These runs observe regions of sky that are long in right ascension and narrow in declination. Each run is composed of observations from six camcols: the six sets of five CCDs (one for each of the photometric bands) that fill the SDSS focal plane. The SDSS photometry is used to select targets for fol ...
Statistical properties of a sample of periodically variable B-type supergiants ⋆
... Waelkens et al. (1998) positioned the new periodic B supergiants in the HR diagram on the basis of multicolour photometric calibrations (accurate parallaxes are not available) and found them to be situated between the SPBs and previously known α Cyg-type variables (see their Fig. 2). Oscillations we ...
... Waelkens et al. (1998) positioned the new periodic B supergiants in the HR diagram on the basis of multicolour photometric calibrations (accurate parallaxes are not available) and found them to be situated between the SPBs and previously known α Cyg-type variables (see their Fig. 2). Oscillations we ...
Dust attenuation in galaxies up to redshift 2 V. Buat
... formation rate (SFR) in the universe and its evolution with redshift from UV-optical surveys. The search for relations between dust attenuation and observed or commonly measured quantities are very useful in this context. It is also particularly important to study the dependence of dust attenuation ...
... formation rate (SFR) in the universe and its evolution with redshift from UV-optical surveys. The search for relations between dust attenuation and observed or commonly measured quantities are very useful in this context. It is also particularly important to study the dependence of dust attenuation ...
The role of tidal interactions in star formation
... protostellar accretion (Larson 1982, 1990b), but the frequency of close passages is probably too small for purely random encounters to be very important, even in dense clusters like the Orion Nebula cluster (Scally & Clarke 2001). The importance of interactions is greatly increased, however, if most ...
... protostellar accretion (Larson 1982, 1990b), but the frequency of close passages is probably too small for purely random encounters to be very important, even in dense clusters like the Orion Nebula cluster (Scally & Clarke 2001). The importance of interactions is greatly increased, however, if most ...
White dwarfmain sequence binaries identified within SDSS DR7 and
... Gómez-Morán & Schwope (2007) also developed special colourcuts to select old WDMS systems from the Sloan Extension for Galactic Understanding and Exploration (SEGUE), but they did not consider the fact that the colours change with different surface gravities of white dwarfs and metallicities of co ...
... Gómez-Morán & Schwope (2007) also developed special colourcuts to select old WDMS systems from the Sloan Extension for Galactic Understanding and Exploration (SEGUE), but they did not consider the fact that the colours change with different surface gravities of white dwarfs and metallicities of co ...
Microlensing Events by Proxima Centauri in 2014 and 2016
... between the parallaxes of the lens and the source. The parallax of the lens is already known, and our planned HST observations will directly constrain the source parallaxes (expected to be very small as noted above). For the upcoming close encounters of Proxima Centauri, the sources lie on either si ...
... between the parallaxes of the lens and the source. The parallax of the lens is already known, and our planned HST observations will directly constrain the source parallaxes (expected to be very small as noted above). For the upcoming close encounters of Proxima Centauri, the sources lie on either si ...
Cosmic distance ladder
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are ""close enough"" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.The ladder analogy arises because no one technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.