Speaker
Description
Nuclear reactions involving $^{12}$C and $^{16}$O are key for the chemical evolution of massive stars during their advanced burning phases. These reactions shape the stellar structure, the evolution up to the pre-supernova stage and, ultimately the nature of the compact remnant.
In this talk, I will present our work exploring the impact and consequences of different nuclear reaction rates from both experimental and theoretical studies: firstly for the $^{12}$+$^{12}$C reaction alone, and secondly with three linked reactions: $^{12}$C($\alpha$,$\gamma$)$^{16}$O, $^{12}$C+$^{16}$O and $^{16}$O+$^{16}$O.
Using the stellar evolution code GENEC, we computed non-rotating and rotating models of massive stars for different masses at solar metallicity. We found that variations in nuclear rates modify the $^{12}$C/$^{16}$O ratio at He-exhaustion, the C-, Ne-, and O-burning lifetimes, the ignition conditions, and the chemical structure. These changes, in turn, influence the chemical abundances as well as the compactness and type of remnant formed at the end of stellar life, highly sensitive to the amount of $^{12}$C and core structure.
Our results highlight that access to new and accurate determinations of reaction rates can significantly affect key aspects of massive stars evolution, from stellar burning lifetimes to nucleosynthesis and stellar fate. These effects accumulate over time and must be accounted to improve predictions of stellar evolution and supernova progenitor properties (Dumont et al. 2024, 2025). However, other aspects must also be considered in this context. I will also introduce how the impact of the different approaches used to describe rotation in our models may affect these outcomes and how their effect along evolution can further shape the evolutionary outcomes of massive stars (Dumont et al. in prep.).