45.52 grams. Various
TKW 3.95 kg.
Pre-Earth-encounter size estimated to be 4.1 meters in diameter and 80,000 kilograms.
Observed approach: 6 October 2008
Observed fall: 7 October 2008
First found: 6 December 2008, Nahr an Nil, Nubian Desert, Sudan.
Many stones from this fall have been classified, with a wide variety of results - Ureilite, polymict, anomalous; bencubbin; EH 4/5; and EL 3.
From the MetBul:
On October 6, 2008, a small asteroid called 2008 TC3 was discovered by the automated Catalina Sky Survey 1.5 m telescope at Mount Lemmon, Tucson, Arizona, and found to be on a collision course with Earth. Numerous astronomical observatories followed the object until it entered the Earth’s umbra at Oct. 7.076 UTC the next day. The astrometric position of 295 observations of 2008 TC3 over the period Oct. 6.278 to Oct. 7.063 was used to calculate the approach trajectory over the impact location in northern Sudan. The object exploded at a high ~37 km altitude over the Nubian Desert, and as a result the meteorites are spread over a large area. A search was organized by the University of Khartoum on Dec. 2–9, led by P. Jenniskens (SETI Institute) and M. H. Shaddad (Khartoum).
    
Siegfried writes:
ALMAHATA SITTA MS 172 - ORIENTED METEORITE FROM THE ASTEROID 2008 TC3.
Ureilite. 34 x 32 x 19mm (1.25 x 1.25 x 0.75 inches) and 45.52 grams.
On loan from Siegfried Beutel until 6 January 2019 to Muséum National d'Histoire Naturelle
ALMAHATA SITTA METEORITE - FROM THE ONLY ASTEROID EVER TRACKED PRIOR TO EARTH IMPACT
Ureilite - URE anom
Nahr an Nil, Sudan - (20° 44' 45"N, 32° 24' 46"E)
On October 6, 2008, Richard Kowalski discovered a new asteroid as part of a congressionally mandated mission to attempt to identify and inventory NEOs (near-Earth objects) that pose a hazard to Earth. Richard, also a meteorite collector, has discovered thousands of asteroids over the years. This night was different, though, because when his observations were reported to the Minor Planet Center in Cambridge Massachusetts, an orbit computation immediately determined that the object, named 2008 TC3, was on a collision course with Earth! Within hours, observatories around the world were trained on its approach as astronomers assessed the threat - a scenario that until that moment had been the stuff of science fiction. Never before had an asteroid been observed in space and tracked prior to Earth impact, which NASA's Jet Propulsion Laboratory determined would occur within a day. When 2008 TC3 entered the atmosphere, it was traveling at 29,000 miles per hour. When it exploded dozens of miles above Earth's surface, it unleashed the energy of at least a kiloton of TNT. A blinding light was reported in the vicinity, and the pilots of a passenger jet more than 850 miles away reported the bright flash. Luckily, 2008 TC3 was small and landed as predicted in the Nubian Desert of Northern Sudan.
A search of the anticipated impact zone resulted in the recovery of only 37 metoerites adding to a total weight of 3.95 kg - the vast majority of this mass having vaporized or disintegrated on impact with the atmosphere. In accordance with the guidelines of the Nomenclature Committee of the Meteoritical Society, former NEO 2008 TC3 became Almahata Sitta, Arabic for "Station Six," a station stop on the rail line to Khartoum. Almahata Sitta is a most unusual meteorite, and not only as a result of its grand entrance. This complete specimen is of the enstatite chondrite [subtype EL6] variety. Fusion encrusted, the reverse of this specimen has a pronounced rollover lip of fusion crust, which indicates that this meteorite did not spin or tumble as most meteorites do when they experience frictional heating in Earth's atmosphere. The rarity and scientific importance of Almahata Sitta cannot be overstated. A special edition of Meteoritics and Planetary Science as well as a National Geographic Special were devoted uniquely to the Almahata Sitta event.
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