Asteroseismic Constraints on the Models of Hot B Subdwarfs: Convective Helium-Burning Cores [SSA]

http://arxiv.org/abs/1612.02507


Asteroseismology of non-radial pulsations in Hot B Subdwarfs (sdB stars) offers a unique view into the interior of core-helium-burning stars. Ground-based and space-borne high precision light curves allow for the analysis of pressure and gravity mode pulsations to probe the structure of sdB stars deep into the convective core. As such asteroseismological analysis provides an excellent opportunity to test our understanding of stellar evolution. In light of the newest constraints from asteroseismology of sdB and red clump stars, standard approaches of convective mixing in 1D stellar evolution models are called into question. The problem lies in the current treatment of overshooting and the entrainment at the convective boundary. Unfortunately no consistent algorithm of convective mixing exists to solve the problem, introducing uncertainties to the estimates of stellar ages. Three dimensional simulations of stellar convection show the natural development of an overshooting region and a boundary layer. In search for a consistent prescription of convection in one dimensional stellar evolution models, guidance from three dimensional simulations and asteroseismological results is indispensable.

Read this paper on arXiv…

J. Schindler, E. Green and W. Arnett
Fri, 9 Dec 16
39/62

Comments: 10 pages, 3 figures, proceedings of the Joint TASC2 – KASC9 Workshop – SPACEINN – HELAS8 Conference “Seismology of the Sun and the Distant Stars 2016”. To be published by the EPJ Web of Conferences