Mass range of hot subdwarf B stars

Maja Vučković
Instituto de Física y Astronomía
Facultad de Ciencias
Universidad de Valparaíso, CL

Sala Seminari Villa Magliola



Hot subdwarf B (sdB) stars are helium core burning stars that have lost almost their entire hydrogen envelope due to binary interaction.

Their assumed canonical mass of 0.47 M has recently been debated given a broad range found both from observations as well as from the simulations. In this talk I will show you the recent efforts to revise and refine the mass range of sdB stars derived two decades ago using the stellar evolution code MESA.
I will discuss the effects of metallicity and the inclusion of core overshooting during the main sequence evolution.

This study shows an excellent agreement for low-mass progenitors, up to about 2.0 M. For stars more massive than about 2.5 M we obtain a wider range of sdB masses compared to the simulations.
Finally, I will show the results for the sdB lifetime as a function of sdB mass and discuss the effect this might have in the comparison between simulations and observational samples.
This study paves the way for reproducing the observed Galactic mass distribution of sdB binaries.

Canali di formazione delle subnane blu

Referente locale: Roberto Silvotti
Responsabile seminari OATo: Paolo Giacobbe– Mario Damasso