2008 TC3

Ground path of the meteoroid over Sudan. The red line is the object's path, terminating where it would have hit the ground. The green line is the infrasound detection of the object's explosion. METEOSAT IR fireball location indicated by orange crosshairs. Predicted altitude as the object crossed the Nile River and several other points are listed. Exact path and fireball altitude have not been confirmed.

2008 TC₃ (Catalina Sky Survey temporary designation 8TA9D69) was a meteoroid 2 to 5 meters (7 to 16 ft) in diameter that entered Earth's atmosphere on October 7, 2008, at 02:46 UTC (5:46 a.m. local time) and burned up before it reached the ground.^[1]

Discovery

The meteoroid was notable as the first such body to be observed and tracked prior to reaching Earth.^[4] The process of detecting and tracking a near-Earth object, an effort sometimes referred to as Spaceguard, was put to a test. In total, 586 astrometric and almost as many photometric observations were performed by 27 amateur and professional observers in less than 19 hours and reported to the Minor Planet Center, which issued 25 Minor Planet Electronic Circulars with new orbit solutions in eleven hours as observations poured in. Impact predictions were performed by University of Pisa's CLOMON 2 semi-automatic monitoring system^[5]^[6] as well as Jet Propulsion Laboratory's Sentry system. Spectral observations that were performed by astronomers at the 4.2 meter William Herschel Telescope at La Palma, Canary Islands are consistent with either a C-type or M-type asteroid.

Explosion

The object is confirmed to have entered Earth's atmosphere as a meteor above northern Sudan at a velocity of 12.8 kilometres per second (8.0 mi/s). Estimated trajectory has the object coming out of the western sky at an azimuth of 281 degrees, and an altitude angle of 19 degrees to the local horizon.

It exploded tens of kilometers above the ground with the energy of 0.9 to 2.1 kilotons of TNT, causing a large fireball or bolide^[7] in the early morning sky.^[8] Very few people inhabit the remote area of the Nubian Desert where the explosion took place; The Times, however, reported that the meteoroid's "light was so intense that it lit up the sky like a full moon and an airliner 1,400 km (870 miles) away reported seeing the bright flash."^[9] A low-resolution image of the explosion was captured by the weather satellite Meteosat 8.^[10] The Meteosat images place the fireball at 21°00′N 32°09′E / 21.00, 32.15.^[11] Infrasound detector arrays in Kenya also detected a sound wave from the direction of the expected impact corresponding to energy of 1.1 to 2.1 kilotons of TNT.^[12] Meteoroids of this size hit Earth about two or three times a year.^[13]