Lunch talk on Jun. 14, 2023

Grids of Wolf-Rayet Stars Using MESA with the k-omega Model: From 25 to 120 M_sun at Z = 0.02

Speaker: Zhi Li (YNO)

Venue: SWIFAR Building 2111

Time: 12:30 PM, Wednesday, Jun. 14, 2023

Abstract: 

To explore overshoot mixing and rotational mixing beyond the convective core during the core He-burning phase in massive stars, we computed a grid of stellar models with the k-omega model, both rotating and non-rotating, at Z = 0.02, covering a mass range of 25 to 120 M⊙. The rotating models start on the zero-age main-sequence with a rotation rate v_ini/v_crit = 0.4, and the evolution is computed until the end of the central carbon-burning phase. Models with the k-omega model provide larger convective cores and a broadening of the main-sequence width. The final masses of the WR stars ranging from 9.5-17.5 M⊙ and 10-23 M⊙ for the rotating and non-rotating models, respectively. In the rotating models, the C/N ratio decrease slowly below 0.1 outside the convective core, resulting in a flatter element transition region. In addition, the lifetimes of WNC phase are (1-4)×10^4 yr, which is about one order of magnitude longer than the non-rotating models. The expected WNC/WR ratios are 0.059 and 0.004 for the rotating and non-rotating models respectively.