2007_TU24
2007 TU24 is an Apollo near-Earth asteroid that was discovered by the Catalina Sky Survey in Arizona on 11 October 2007. Imaging radar has estimated that it is 250 meters (820 ft) in diameter.[3] The asteroid passed 554,209 kilometer (344,370 mile or 1.4-lunar distance)[5] from Earth on 29 January 2008 at 08:33 UTC. (At the time of the passage it was believed the closest for any known potentially hazardous asteroid (PHA) of this size before 2027,[6] but in 2010 2005 YU55 was measured to be 400 meters in diameter.) At closest approach 2007 TU24 had an apparent magnitude of 10.3 and was about 50 times fainter than the naked eye can see. It required about a 3-inch (76 mm) telescope to be seen.[3]