NBIA Colloquium via Zoom by Brian Fields

We would like to invite you to this week’s (Zoom) Colloquium on

                          Friday, Feb 5 at 3:15 PM

Speaker: Brian Fields (University of Illinois, Champaign-Urbana)

Title: When Stars Attack!  Near-Earth Supernova Explosions Revealed by Deep-Ocean and Lunar Radioactivity

Abstract: Supernova explosions are multimessenger particle engines, they create many of the elements essential for planets and life, and they play central roles in galaxy evolution.  Yet these awesome events take a sinister shade when they occur close to home, because an explosion nearby can pose a grave threat to Earthlings. We will show how radionuclides produced by supernovae can reveal nearby events in the geologic past, and we will highlight isotopes of interest. In particular, geological evidence for live 60Fe has recently been confirmed globally in multiple sites of deep-ocean material, in cosmic rays, and in lunar samples. We will review astrophysical 60Fe production sites and show that the data demand that at least one core-collapse supernova exploded near the Earth over the past few Myr, and explain how debris from the explosion was transported to the Earth as a “radioactive rain.” Deep-ocean and lunar 60Fe measurements thus represent a laboratory for supernova astrophysics, but also with implications for geology, astrobiology, and possibly terrestrial evolutionary biology.

Bio: Brian Fields received his PhD from University of Chicago, and was a postdoc at the Institut d'Astrophysique, U of Notre Dame, and U Minnesota. He is now faculty at the University of Illinois, in Astronomy and Physics. He is a theorist interested in particle and nuclear astrophysics and cosmology, particularly big-bang nucleosynthesis, supernovae, cosmic rays, gamma rays, and neutrinos.

To participate on Friday, click on

https://ucph-ku.zoom.us/j/61333932427 

The colloquium will be moderated by Mauricio Bustamante and we strongly encourage you to participate actively by asking questions during the talk. Mauricio will briefly remind you how this can be done just before the colloquium starts.