Volume 539, March 2012
|Number of page(s)||8|
|Section||Stellar structure and evolution|
|Published online||17 February 2012|
A preliminary look at the empirical mass distribution of hot B subdwarf stars
1 Département de Physique, Université de Montréal, Succ. Centre-Ville, CP 6128, Montréal, QC, H3C 3J7, Canada
2 Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
3 CNRS, IRAP, 14 Av. E. Belin, 31400 Toulouse, France
4 Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
5 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
6 Institut d’Astrophysique et de Géophysique de l’Université de Liège, Allée du 6 Août 17, 4000 Liège, Belgium
7 FNRS, rue d’Egmont 5, 1000 Bruxelles, Belgium
Received: 7 October 2011
Accepted: 12 December 2011
We present the results of about a decade of efforts toward building an empirical mass distribution for hot B subdwarf stars on the basis of asteroseismology. So far, our group has published detailed analyses pertaining to 16 pulsating B subdwarfs, including estimates of the masses of these pulsators. Given that measurements of the masses of B subdwarfs through more classical methods (such as full orbital solutions in binary stars) have remained far and few, asteroseismology has proven a tool of choice in this endeavor. On the basis of a first sample of 15 pulsators, we find a relatively sharp mass distribution with a mean mass of 0.470 M⊙, a median value of 0.470 M⊙, and a narrow range 0.441−0.499 M⊙ containing some 68.3% of the stars. We augmented our sample with the addition of seven stars (components of eclipsing binaries) with masses reliably established through light curve modeling and spectroscopy. The new distribution is very similar to the former one with a mean mass of 0.470 M⊙, a median value of 0.471 M⊙, and a slightly wider range 0.439−0.501 M⊙ containing some 68.3% of the stars. Although still based on small-number statistics, our derived empirical mass distribution compares qualitatively very well with the expectations of stellar evolution theory.
Key words: stars: fundamental parameters / stars: oscillations / subdwarfs
© ESO, 2012
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.