Astrophysical shrapnel: Discriminating among near-Earth stellar explosion sources of live radioactive isotopes

Brian J. Fry, Brian D. Fields, John R. Ellis

Research output: Contribution to journalArticle

Abstract

We consider the production and deposition on Earth of isotopes with half-lives in the range 105-108 yr that might provide signatures of nearby stellar explosions, extending previous analyses of Core-Collapse Supernovae (CCSNe) to include Electron-Capture Supernovae (ECSNe), Super-Asymptotic Giant Branch (SAGB) stars, Thermonuclear/ Type Ia Supernovae (TNSNe), and Kilonovae/Neutron Star Mergers (KNe). We revisit previous estimates of the 60Fe and 26Al signatures, and extend these estimates to include 244Pu and 53Mn. We discuss interpretations of the 60Fe signals in terrestrial and lunar reservoirs in terms of a nearby stellar ejection ∼2.2 Myr ago, showing that (1) the 60Fe yield rules out the TNSN and KN interpretations, (2) the 60Fe signals highly constrain SAGB interpretations but do not completely them rule out, (3) are consistent with a CCSN origin, and (4) are highly compatible with an ECSN interpretation. Future measurements could resolve the radioisotope deposition over time, and we use the Sedov blast wave solution to illustrate possible time-resolved profiles. Measuring such profiles would independently probe the blast properties including distance, and would provide additional constraints for the nature of the explosion.

Original languageEnglish (US)
Article number71
JournalAstrophysical Journal
Volume800
Issue number1
DOIs
StatePublished - Feb 10 2015

Keywords

  • Astrobiology
  • Dust, extinction
  • ISM: supernova remnants
  • Nuclear reactions, nucleosynthesis, abundances
  • Stars: AGB and post-AGB
  • Supernovae: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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