Mass loss and its stellar feedback of massive stars with different metallicities

Po-Sheng Ou^1,2*, Ke-Jung Chen¹

¹Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan
²Department of Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Po-Sheng Ou, email:psou@asiaa.sinica.edu.tw

We present a systematic study of the mass loss of massive stars. Mass loss plays a vital role in the evolution of massive stars, and it is suggested to depend on metallicity. However, the total mass loss during the lifetimes of massive stars with different metallicities is still unclear. In this paper, we use 1D stellar evolution models to understand the physics of mass loss and its dependence on stellar metallicity. We consider different stellar mass and metallicity to build up a grid of ~2000 models. Stellar winds, containing hot main-sequence wind and cool supergiant wind, are the main drivers to the mass loss of massive stars in our models. Our results demonstrate the existence of a critical metallicity $Ｚ_c$ at the absolue metallicity $Z~10^{-3}$, around which the mass loss shows dramatic behaviors. With a $Z> Ｚ_c$, massive stars tend to evolve into the red supergiants, then trigger a robust cold wind through dust formation. On the other hand, if $Z < Z_c $, massive stars would remain compact and evolve into the blue supergiants, in which cold wind is not active, and the mass loss is generally weak. Besides, we also calculate feedback of mass loss, which yields momentum and energy for a $10^5-M_{\odot}$ star cluster with the Salpeter IMF. Our results provide realistic stellar wind feedback models, which are useful for the galaxy and ISM simulations.

Keywords: Stellar wind, Stellar feedback, Mass loss