2008 TC3

The blue line represents the trajectory of the meteoroid approaching the earth

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.

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 making physical contact with the ground.

Discovery

The meteoroid was discovered by an observer at the Catalina Sky Survey (CSS) 1.5 meter telescope at Mount Lemmon, north of Tucson, Arizona, USA about a day before the impact.

The meteoroid was notable as the first such body to be observed and tracked prior to reaching Earth. The process of detecting and tracking a near-Earth object, an effort sometimes referred to as Spaceguard, was put to a test. In total, 570 astrometric and almost as many photometric observations were performed 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 as well as Jet Propulsion Laboratory's Sentry system. Spectral observations were performed by astronomers at the 4.2 meter William Herschel Telescope at La Palma, Canary Islands.

Explosion

The meteoroid, also considered a bolide due to its fiery explosion, is confirmed to have entered Earth's atmosphere 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.

Meteosat / EUMETSAT IR image of the 2008 TC3 explosion. Copyright 2008 EUMETSAT

It exploded tens of kilometers above the ground with the energy of around one kiloton of TNT, causing a large fireball in the early morning sky. 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." A low-resolution image of the explosion was captured by the weather satellite Meteosat 8. 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. Meteoroids of this size hit Earth about two or three times a year.

The trajectory showed intersection with Earth's surface at roughly 20.3° north, 33.5° east, though the object was expected to break up perhaps 100–200 kilometers west as it descended, somewhat east of the Nile River, and about 100 kilometers south of the Egypt–Sudan border.

External links

External image
An image of 2008 TC3

• Remanzacco Observatory photographs of the incoming space rock
• Animation of impact from the asteroid's point of view (Pasquale Tricarico of the Planetary Science Institute)
• News bulletin from NASA Near Earth Object Program
• Impact Trajectory on October 7, 2008
• Circled, the object caught on camera as it sped towards Earth
• The full story of Earth-impacting asteroid 2008 TC₃ by Emily Lakdawalla (The Planetary Society Blog)
• 2008 TC3: A Serendipitous Event by Tavi Greiner (The Slooh SkyLog)