Quasi-Hydrostatic Evolution of Massive Population III Stars
Abstract
Recently, Straka & Tscharnuter (2001, A&A 372, 579) showed that in the case of massive Population III stars ( > 20 Msolar) β-decay reactions and the 13N(p,γ)14O reaction must be included in evolutionary calculations. It was also shown that in these zero-metal stars the assumption of instantaneous mixing across convective regions is not fulfilled. We present first results of our latest evolutionary model calculations starting from the pre-main sequence phase until the depletion of hydrogen on the main sequence. This model, for the first time, does not make any assumption about nuclear equilibria nor instantaneous mixing while also including the above mentioned reaction chains in the CNO-cycle. In particular, we solve a time-dependent nuclear reaction network that is fully coupled to the hydrostatic stellar structure. Mixing is treated as a time-dependent diffusion process where the mixing efficiency is determined by an additional equation for the turbulent kinetic energy taken from Kufuß (1986, A&A 160, 116) that models convection in a time-dependent fashion.
- Publication:
-
Astronomische Gesellschaft Meeting Abstracts
- Pub Date:
- 2001
- Bibcode:
- 2001AGM....18..P74S