2026/10/15(Thu) 10:30 -11:30 七樓研討室 7F, P7A Seminar Room
Title
Galactic Chemical Evolution of r-process elements, and with short-lived radioactive isotopes
Speaker
Dr. Benjamin Wehmeyer (University of Wroclaw)Abstract
The origin of the heaviest elements is still a matter of debate. For the rapid neutron capture process (r-process), multiple sites have been proposed, e.g., neutron star mergers and (sub-classes) of supernovae. R-process elements have been measured in a large fraction of metal-poor stars. Galactic archaeology studies show that the r-process abundances among these stars vary by over 2 orders of magnitude. On the other hand, abundances in stars with solar-like metallicity do not differ greatly. While the large scatter at low metallicities might point to a rare production site, why is there barely any scatter at solar metallicities?
In this talk, I will discuss chemical evolution scenarios that provide an explanation for the observed abundance features of r-process elements in our Galaxy, especially at the lowest metallicities.
Further, I will explain how adding short lived radioisotopes to the model can help to further constrain the r-process and other processes, and explain why certain short lived radioisotopes arrive conjointly on Earth, even though they were produced at different nucleosynthesis sites.
Finally, I included radioisotope production into a cosmological zoom-in simulation to create a map of Al-26 decay gamma-rays indicating areas of ongoing star formation in the Galaxy, consistent with the observations by the SPI/INTEGRAL instrument. To complement, I will also provide predictions for future gamma-ray detection instruments.
Language
演講語言 (Language): in English