| Name: Ashique T |
| Affiliation: Indian Institute of Technology Palakkad |
| Conference ID: ASI2026_428 |
| Title: Effect of overshoot mixing on black hole mass gap |
| Abstract Type: Poster |
| Abstract Category: Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Author(s) and Co-Author(s) with Affiliation: T Ashique(Indian Institute of Technology Palakkad), Projjwal Banerjee(Indian Institute of Technology Palakkad) |
| Abstract: Pulsational Pair Instability Supernovae (PPISNe) and Pair Instability Supernovae (PISN) are predicted to result in a stellar black hole mass gap ranging from $\sim 90\hbox{--}260\,M_\odot$ from single first- and early-generation massive stars as they do not undergo much mass loss. The lower edge of the mass gap corresponds to a maximum mass of $\sim 37\,M_\odot$ for the CO core above which pair instability leads to PPISN, resulting in the loss of the envelope. Here, we explore the effect of overshoot mixing on the mass of the CO core in first-generation non-rotating stars. We find that dredge-up induced by overshoot mixing occurs stochastically in some models, both during and after core He burning. This can dramatically reduce the size of CO cores such that stars of initial mass of $\sim 100\hbox{--}150\,M_\odot$ can have a CO core of $\lesssim 37\,M_\odot$, leading to the entire star, including the envelope, collapsing to a black hole. This dramatically increases the lower edge of the black hole mass gap up to $\sim 150\,M_\odot$ and populates black holes within the purported mass gap. We discuss the impact of this for future gravitational wave detection in LIGO-Virgo-Kagra. |
