Astrophysics Seminar: Emily Griffith, The Ohio State University


Location: 184 Nieuwland Science Hall (View on map )

Abundance ratio trends in the Milky Way disk and their implications for nucleosynthesis

Emily Griffith
Graduate Student
The Ohio State University

Our understanding of the origin of the elements is grounded in observational abundance measurements and theoretical models of stellar explosions. The current era of big data from surveys such as APOGEE, GALAH, and Gaia allows us to study an unprecedented number of stars in abundance, velocity, and position space. I use the results of these surveys to understand the prompt and delayed contributions to over 20 elements. By modeling stellar abundances as the sum of a core collapse supernovae (CCSN) and a Type-Ia supernovae component, I study abundance trends in [X/Mg] vs. [Mg/H] space to empirically determine the fractional contribution of CCSN to observed elements, identify stars with abundances that differ from those predicted by our model, and compare empirical and theoretical constraints on theCCSN explodability landscape. In this talk I will highlight my interesting results including an empirically derived Na origin with a strong delayed contribution and signatures of an alternative delayed enrichment source in heavy elements such as asymptotic giant branch stars. I will discuss theoretical CCSN models and the black hole landscape (which masses of massive stars explode vs. collapse), showing that the chosen black hole landscape affects the predicted abundance ratios. I compare theoretical yields with empirical results and conclude that no landscape agrees with all observational constraints, though I identify possible adjustments to the models to bring them into better agreement.

Hosted by Dr. Nicolas Lehner

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