SETI Institute, Public Affairs Office
July 19, 2012
Stowaways in a small car-sized asteroid that crashed in northern Sudan in 2008 have revealed what happened to a mysterious dwarf planet that is dusting Earth with a rare type of meteorites. That dwarf planet did not survive the “Late Heavy Bombardment” that cratered the Moon surface, an international team of researchers report in the latest issue of the journal Meteoritics and Planetary Science.
“The 2008 asteroid was a small chunk of a dwarf planet that once shattered into pieces,” says consortium lead Dr. Peter Jenniskens of the SETI Institute and NASA Ames Research Center. Jenniskens and co-author Dr. Muawia Shaddad recovered fragments of the asteroid, called 2008 TC3, by searching for meteorites with students of the University of Khartoum shortly after the fall in October of 2008. The recovered meteorites are named Almahata Sitta after the fall area in Sudan.
When the dwarf planet broke up, it left a debris field in the asteroid belt between Mars and Jupiter that now supplies a steady flow to Earth of the meteorites called ureilites. The dwarf planet is known as the Ureilite Parent Body. Ureilites contain very low levels of uranium, thorium and potassium, the elements that have long-lived radioactive isotopes, making it difficult for researchers to measure the times of catastrophic heating and disruption events for ureilites.