Nicolas Rodriguez-Segovia

Sub-dwarf B stars with COMPAS and MESA

Sub-dwarf B (sdB) stars are low-mass stars that have a thin outer hydrogen layer and helium-burning interior, usually corresponding to the exposed cores of stars near the tip of the red giant branch. However, the process through which they lose most of their hydrogen rich envelope is not completely clear. Amongst possible formation scenarios, binary evolution is the most accepted, encompassing both stable and unstable mass transfer as well as mergers. To have a better understanding of the characteristics of these different formation channels and the current-day sdB population, we use the rapid binary population synthesis (BPS) code COMPAS (Compact Object Mergers: Population Astrophysics and Statistics) to investigate production pathways of these low-mass stars for the first time. We also adapt results from detailed modelling of sdBs with MESA from the literature, apply them to our population synthesis results and further improve the estimates about the physical properties of our population. We discuss our results by comparing them against previous studies available in the literature, highlight agreement with observables and propose potential applications.