%V 45
%I Wiley
%P 1743-1750
%T Cosmogenic radioisotopes in the Almahata Sitta ureilite
%J Meteoritics and Planetary Science
%N 10-11
%R 10.1111/j.1945-5100.2010.01135.x
%X Asteroid 2008 TC3 was predicted to fall in Sudan on October 7, 2008, and 2 months later, 15 meteorite fragments were recovered from the Nubian Desert. Most of these fragments were classified as polymict ureilites. In the largest ureilitic fragment #15, weighing 75 g, we have measured six gamma emitting radionuclides (46Sc, 57Co, 54Mn, 22Na, 60Co, and 26Al) by nondestructive whole rock counting using a sensitive gamma-ray spectrometer. The activities of 60Co, produced mainly by neutron capture in cobalt, and 26Al indicate that fragment #15 was located at a depth of 41 ? 14 cm inside the 1.5?2 m radius asteroid. The activity of other radionuclides is also consistent with this shielding depth within the asteroid. The 22Na/26Al activity ratio is higher than expected for the average cosmic ray flux, probably due to the unusually prolonged solar minimum before the fall.
%L eprints2360
%D 2010
%A Carla Taricco
%A Narendra Bhandari
%A Paolo Colombetti
%A Alberto Romero
%A Gianna Vivaldo
%A Neeharika Sinha
%A Peter Jenniskens
%A Muawia H. Shaddad
%A G. M. Ballabh