The Galactic Chemical Evolution of Heavy Elements


The astrophysical sites which dominate the production of r-process elements have been a matter of contention for decades. The event GW170817/AT2017gfo, with the confirmed observation of the neutron-capture element strontium, originally raised hopes that neutron star mergers (NSM) could be a leading contributor to the production of heavy elements. However, galactic chemical evolution (GCE) models which take into account the rates of NSM events show that the onset of NSM occurs too late in the enrichment history to explain the abundance patterns of extremely metal poor stars. Among the other candidates is the small fraction of core-collapse supernovae whose progenitor star rotates sufficiently fast and creates magneto-hydrodynamic jets (MHDJ) capable of yielding r-process enrichment. It is possible that the rarity of such events may be offset by the larger rates and mass ejecta. After an introduction on GCE modeling, I will present results which include novel yield tabulations of neutron-capture events. I will explore the dependence of neutron-capture element abundances on theoretical NSM rates, as well as on future GW missions. We investigate some variation of parameters in single-zone GCE models for both the Milky Way and dwarf galaxies. On a s-process production baseline by AGB and core-collapse SNe, we estimate which conditions favor one r-process enrichment scenario over the other.

Dr. Eda Gjergo (@Wuhan University)
Online Zoom Meeting ID: 822 8287 7472 , Passcode: astroPKU , Link:
Monday, April 18, 2022 - 1:30PM to Monday, April 18, 2022 - 2:20PM