Supernova Triggers for End-Devonian Extinctions

Abstract

The Late Devonian was a protracted period of low speciation resulting in biodiversity decline, culminating in extinction events near the Devonian-Carboniferous boundary. Recent evidence indicates that the final extinction event may have coincided with a dramatic drop in stratospheric ozone, possibly due to a global temperature rise. Here we study an alternative possible cause for the postulated ozone drop: a nearby supernova explosion that could inflict damage by accelerating cosmic rays that can deliver ionizing radiation for up to $\sim 100$ kyr. We therefore propose that the end-Devonian extinctions were triggered by supernova explosions at $\sim 20$ pc, somewhat beyond the "kill distance" that would have precipitated a full mass extinction. Such nearby supernovae are likely due to core-collapses of massive stars; these are concentrated in the thin Galactic disk where the Sun resides. Detecting either of the long-lived radioisotopes Sm-146 or Pu-244 in one or more end-Devonian extinction strata would confirm a supernova origin, point to the core-collapse explosion of a massive star, and probe supernova nucleosythesis. Other possible tests of the supernova hypothesis are discussed.

3 pages, no figures. Matches published version. Creative Commons CC BY-NC-ND license

References in corpus (8)

• Multi-messenger Observations of a Binary Neutron Star Merger
• Astrophysical Ionizing Radiation and the Earth: A Brief Review and Census of Intermittent Intense Sources
• Astrophysical Shrapnel: Discriminating Among Near-Earth Stellar Explosion Sources of Live Radioactive Isotopes
• Terrestrial Effects Of Nearby Supernovae In The Early Pleistocene
• Solar irradiance changes and photobiological effects at Earth's surface following astrophysical ionizing radiation events
• From cosmic explosions to terrestrial fires?
• Photobiological effects at Earth's surface following a 50 pc Supernova
• Near-Earth Supernova Explosions: Evidence, Implications, and Opportunities