AAS 205th Meeting, 9-13 January 2005
Session 107 Binary Stars Including Theory and Activity
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

Previous   |   Session 107   |   Next

[107.16] Faint Companions in Post-Common Envelope Subdwarf B Star Binaries

E. M. Green, B.-Q. For (Steward Observatory, U. Arizona)

Radial velocity surveys show that approximately half of subdwarf B (sdB) stars are in post-common envelope binaries with orbital periods between a few hours and several days. The secondary companions are undetectable in optical spectra, and their mass functions indicate that nearly all must be white dwarfs or low mass main sequence stars. We present the observed distribution of orbital periods, velocity amplitudes, and minimum secondary masses for a complete, kinematically unbiased sample of short period sdB binaries. We show how additional information from precise light curves and from 2MASS JH colors allows us to discriminate between white dwarf and faint main sequence companions. We present first results from Monte Carlo simulations for various possible distributions of the orbital separation and secondary mass, compare the results with our observed distributions, and discuss implications for common envelope evolution.

Previous   |   Session 107   |   Next

Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.