The distribution of helium-3 in the Grant meteorite and a determination of the original mass
Abstract
The distribution of helium-3 in a slice of the Grant meteorite was determined by exposing it to slow neutrons and counting the converted tritium. The measured values ranged from 6.5 × 10 -63/g to 5.1 × 10 -6 cm 3/g, with the highest value occurring near one edge of the slice. The helium-3 isopleths corresponding to 5.7 × 10 -6 cm 3/g or less form closed loops which are not circles. This indicates that the meteorite was not spherical when it was exposed to extraterrestrial cosmic radiation. The variation of the helium-3 content with depth indicates that the average energy of the cosmic radiation to which it had been exposed was close to 6 BeV. These measurements also indicate that the Grant meteorite, before it struck the earth's atmosphere, was a pear-shaped object with a mass of approximately 880 kg; and that 400 kg ablated from the meteorite in its plunge through the atmosphere.
- Publication:
-
Planetary and Space Science
- Pub Date:
- January 1959
- DOI:
- 10.1016/0032-0633(59)90027-3
- Bibcode:
- 1959P&SS....1...66F