Published by the University of Chicago Press for the Astronomical Society of the Pacific
Publications of the Astronomical Society of the Pacific vol:392 pages:221-224
Hot Subdwarf Stars and Related Objects edition:3 location:Bamberg, Germany date:23-27 July 2007
The sdB star HS 2231+2441 was discovered to be an eclipsing system of the HW Vir type, with a companion below or at the very low mass limit for an M-dwarf system. The low spectroscopic gravity determined for the primary requires the mass of the primary to be less than 0.3Mȯ, indicating that it is not an extreme horizontal branch (EHB) star, but a non helium burning post-RGB star. Evolutionary calculations are consistent with this interpretation and allows the mass to be further constrained.