Department of Astronomy & Physics

Electron capture on Ne-20 and the ultimate fate of medium-mass stars

Speaker: Dr. Oliver Kirsebom (Aarhus University)
Time: January 12, 2018 - 3:00 PM
Location: Atrium 101


Medium-mass stars develop an electron-degenerate core consisting mainly of oxygen and neon, which can become so heavy that it collapses under its own weight. While such a collapse is all but certain to trigger a thermonuclear runaway, the impact on the star is highly uncertain and depends critically on the density at which oxygen ignites, with lower densities favouring disruption of the stellar core and higher densities favouring collapse into a neutron star.
Understanding the final evolution of medium-mass stars is an interesting problem in itself, but it is also necessary if we want to understand how these stars contribute to galactic chemical evolution.
In my talk, I will review what we known about the final evolution of medium-mass stars, explain why electron-capture reactions on Ne-20 nuclei are important in this connection, and discuss ongoing efforts to improve our understanding of these reactions in laboratory experiments.


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