Terrestrial Effects Of Nearby Supernovae In The Early Pleistocene

Recent results have strongly confirmed that multiple supernovae happened at distances ~100 pc consisting of two main events: one at 1.7 to 3.2 million years ago, and the other at 6.5 to 8.7 million years ago.

These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing 60Fe on Earth and the Moon. Other events are indicated by effects in the local cosmic ray (CR) spectrum. Given this updated and refined picture, we ask whether such supernovae are expected to have had substantial effects on the terrestrial atmosphere and biota. In a first cut at the most probable cases, combining photon and cosmic ray effects, we find that a supernova at 100 pc can have only a small effect on terrestrial organisms from visible light, but tropospheric ionization due to the penetration of ≥ TeV cosmic rays will increase by nearly an order of magnitude for thousands of years, and irradiation by muons on the ground and in the upper ocean will increase 20-fold, which will approximately triple the overall radiation load on terrestrial organisms. These effects make possible changes in climate and increased cancer and mutation rates. Further research on the effects of these changes is needed.

Brian C. Thomas (Washburn Univ.), E. E. Engler (Washburn Univ.), M. Kachelrieß (NTNU), A. L. Melott (Univ. Kansas), A. C. Overholt (MidAmerica Univ.), D.V. Semikoz (U. Paris Diderot, Nat. Res. Nuclear U.)
(Submitted on 16 May 2016)

Comments: Submitted to ApJL
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Earth and Planetary Astrophysics (astro-ph.EP); Populations and Evolution (q-bio.PE)
Cite as: arXiv:1605.04926 [astro-ph.HE] (or arXiv:1605.04926v1 [astro-ph.HE] for this version)
Submission history
From: Brian Thomas
[v1] Mon, 16 May 2016 20:04:08 GMT (1055kb)
http://arxiv.org/abs/1605.04926

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