1 / 5

Evidence for nearby SN 2.8Myr ago

Evidence for nearby SN 2.8Myr ago. 60 Fe is produced mainly by type II SNe half life 1.49 Myr Look for 60 Fe in ocean crust layers Date the layers using 10 Be/ 9 Be concentrations Produced by CR Compare crust density with input flux Normalize 60 Fe uptake in the crust using 53 Mn

phila
Download Presentation

Evidence for nearby SN 2.8Myr ago

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Evidence for nearby SN 2.8Myr ago • 60Fe is produced mainly by type II SNe • half life 1.49 Myr • Look for 60Fe in ocean crust layers • Date the layers using 10Be/9Be concentrations • Produced by CR • Compare crust density with input flux • Normalize 60Fe uptake in the crust using 53Mn • Compare ice core with ocean crust concentrations • Further correct by Fe/Mn concentrations in the ocean water • Calculate 60Fe flux • Drop errors because they are getting really big • Wildly speculate about SNe distance

  2. Fig. 1: 60Fe/Fe concentrations vs. age

  3. Effects of nearby SN • Increased CR flux • 15%-ish for 100s of kyr • May affect climate • Correlation seen btwn CR flux and cloud cover • Maybe: CR deplete ozone, more UV gets through • Alters ocean crust dating using 10Be

  4. Fig 2: CR energy density vs. time

  5. Is this real? Solid Evidence • 60Fe spike • Crust layer dating • Absolute flux calibration • SN 60Fe output and transport Wild Speculation

More Related