AAS 205th Meeting, 9-13 January 2005
Session 40 SNe Observations and GRB Milky Way Effects
Oral, Monday, January 10, 2005, 2:00-3:30pm, California

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[40.07] Ozone Depletion Due to a Milky Way Gamma-Ray Burst

B.C. Thomas (U. of Kansas), C. Jackman (NASA GSFC), A. Melott, C. Laird (U. of Kansas), R. Stolarski (NASA GSFC)

Based on cosmological rates, it is probable that at least once in the last Gy the Earth has been irradiated by a gamma-ray burst in our Galaxy from within 2 kpc. Using a two-dimensional atmospheric model we have computed the effects upon the Earth's atmosphere of such a burst. A ten second burst delivering 100 kJ/m2 to the Earth results in globally averaged ozone depletion of over 40 approaching 90 dramatic implications for life since it leads to as much as tenfold increases in solar UVB radiation at the Earth's surface. Widespread extinctions are likely, based on extrapolation from UVB sensitivity of modern organisms.

This work was supported by Neil Gehrels at NASA GSFC and NASA grant NNG04GM41G.

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© 2004. The American Astronomical Society.