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Physics and Astronomy – PhD Defense

July 20, 2018 @ 10:00 am - 12:00 pm

UNC-CH Physics and Astronomy PhD Defense

Jack Dermigny

“The Bizarre Chemical Inventory of NGC-2419: An Investigation of the 30Si(p,g)31P Reaction”

Abundance anomalies in globular clusters provide strong evidence for multiple stellar populations within each cluster. These populations are usually interpreted as distinct generations, with the currently observed second-generation stars having formed in part from the ejecta of massive, first generation “polluter” stars, giving rise to the anomalous abundance patterns. The precise nature of the polluters and their enrichment mechanism are still unclear. Even so, the chemical abundances measured in second-generation stars within the cluster NGC 2419 have provided insight into this puzzling process.

We performed a sensitivity study using Monte Carlo reaction rate network calculations based on a simple enrichment model for NGC 2419. This work suggested four thermonuclear reactions that have a significant impact on the elemental abundances in this cluster. Unfortunately, a firm understanding of the astrophysical source of the pollution material is precluded by their large reaction rate uncertainties.

In the present study, one of these reactions, 30Si(p,g)31P, has been investigated at the Laboratory for Experimental Nuclear Astrophysics (LENA). I will discuss the details of the measurement as well as its impact on the thermonuclear reaction rate.

Details

Date:
July 20, 2018
Time:
10:00 am - 12:00 pm

Venue

Phillips 247