Query : 2009A&A...504L..13Z

2009A&A...504L..13Z - Astronomy and Astrophysics, volume 504, L13-16 (2009/9-4)

The masses of hot subdwarfs.


Abstract (from CDS):

Masses are a fundamental parameter, but they are not well known for most hot subdwarfs. In general, the mass of a hot subdwarf is derived with asteroseismology or dynamical methods, for which it is often difficult to obtain the necessary data from observations. We intend to find an approach to deriving the masses of hot subdwarfs from observational data in the literature. We presented full evolutionary calculations for hot subdwarfs in a wide mass range (0.33M to 1.4M) for a Population I metallicity of Z=0.02, and obtained a relation between Mp and log((Teff4)/(g)), where Mp, Teff, and g are the most probable mass, effective temperature, and gravity. This relation is used to study the masses of some observed hot subdwarfs. We proposed a method of determining the masses of hot subdwarfs. Using this method, we studied the masses of hot subdwarfs from the ESO supernova Ia progenitor survey and Hamburg quasar survey. The study shows that most of subdwarf B stars have masses between 0.42 and 0.54M, whilst most sdO stars are in the range 0.40 ∼0.55M. Comparing our study to the theoretical mass distributions of Han et al. (2003MNRAS.341..669H), we found that sdO stars with mass less than ∼0.5M may evolve from sdB stars, whilst most high-mass(>0.5M) sdO stars result from mergers directly.

Abstract Copyright:

Journal keyword(s): stars: fundamental parameters - stars: horizontal-branch - subdwarfs

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 PG 0014+068 HS* 00 16 54.2537878176 +07 04 30.043437816   15.3       sdO 73 1
2 Feige 48 HS* 11 47 14.4978515760 +61 15 31.789400364   13.12 13.28     sdB 118 0
3 PG 1219+534 HS* 12 21 29.0914917288 +53 04 36.796062144   12.41       sdB 84 1
4 BD-07 3477 HS* 12 44 20.2386233232 -08 40 16.846099536   10.46 10.594 10.895   sdB2VIIHe3 283 1
5 PG 1325+102 HS* 13 27 48.5600155368 +09 54 51.049107756   13.73 13.98 14.29   sdBO 57 1

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