Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-05-23
Astrophys.J. 634 (2005) 509-533
Astronomy and Astrophysics
Astrophysics
Minor revisions, includes more discussion of reaction rates; 1 new figure. Accepted for publication in ApJ. 68 pages, 21 figur
Scientific paper
10.1086/496914
Gamma-Ray Bursts (GRBs) are likely to have made a number of significant impacts on the Earth during the last billion years. We have used a two-dimensional atmospheric model to investigate the effects on the Earth's atmosphere of GRBs delivering a range of fluences, at various latitudes, at the equinoxes and solstices, and at different times of day. We have estimated DNA damage levels caused by increased solar UVB radiation, reduction in solar visible light due to $\mathrm{NO_2}$ opacity, and deposition of nitrates through rainout of $\mathrm{HNO_3}$. For the ``typical'' nearest burst in the last billion years, we find globally averaged ozone depletion up to 38%. Localized depletion reaches as much as 74%. Significant global depletion (at least 10%) persists up to about 7 years after the burst. Our results depend strongly on time of year and latitude over which the burst occurs. We find DNA damage of up to 16 times the normal annual global average, well above lethal levels for simple life forms such as phytoplankton. The greatest damage occurs at low to mid latitudes. We find reductions in visible sunlight of a few percent, primarily in the polar regions. Nitrate deposition similar to or slightly greater than that currently caused by lightning is also observed, lasting several years. We discuss how these results support the hypothesis that the Late Ordovician mass extinction may have been initiated by a GRB.
Cannizzo John Kendall
Ejzak Larissa M.
Gehrels Neil
Hogan Daniel P.
Jackman Charles H.
No associations
LandOfFree
Gamma-Ray Bursts and the Earth: Exploration of Atmospheric, Biological, Climatic and Biogeochemical Effects does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Gamma-Ray Bursts and the Earth: Exploration of Atmospheric, Biological, Climatic and Biogeochemical Effects, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gamma-Ray Bursts and the Earth: Exploration of Atmospheric, Biological, Climatic and Biogeochemical Effects will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-560259