Speaker
Description
Massive stars (10 solar masses and up) play an important role in the synthesis of new elements in the Universe. They enrich the interstellar medium with these newly synthesized isotopes via their stellar winds and via their final supernova explosions. To understand the nuclear yields of these stars, especially before the supernova explosion, there are three key ingredients; the nuclear reaction rates that govern the creation of new isotopes, internal mixing processes that bring the newly synthesized isotopes from the interior of the star to the surface, and the stellar winds that bring these isotopes into the interstellar medium. In our work, we focus on the effects of interior mixing processes on the nucleosynthetic yields. Up to now, the calculations of stellar yields have relied on stellar evolution models that have remained uncalibrated in terms of chemical mixing in the stellar interior. We take the recent observationally driven advances in asteroseismic and binary analysis of the interior structure and evolution of intermediate- to high-mass stars and the proposed mixing profiles based on these observations into account. In this way, our models will bridge the gap between theoretical yield calculations and asteroseismically calibrated mixing profiles. This is a vital step to improve our understanding of the evolution of stars with initial masses of 7-30 solar masses and their role in enriching the galaxy with newly synthesized isotopes. We focus on this mass-range because it includes the most massive asteroseismically constrained stars, and because it covers the stars just below the supernova boundary (8-10 solar masses). Due to the strong dependence between the interior structure of a supernova-progenitor and its final fate, changes in the interior mixing of these stars not only affect the nucleosynthetic yields (both in the stellar winds and from the supernova explosion), but also might affect which stars will end their lives as supernovae and might affect the mass of the supernova remnant. Therefore, a proper understanding of the impact of this calibrated mixing on stellar evolution is especially valuable for the community working on nucleosynthesis and galactic chemical evolution.
