2007 TU24
Radar image of 2007 TU24.
Courtesy NASA/JPL-Caltech |
|||||||
|
Discovery and designation
|
|||||||
|---|---|---|---|---|---|---|---|
| Discovered by | Catalina Sky Survey | ||||||
| Discovery date | October 11, 2007 | ||||||
|
Designations
|
|||||||
| Minor planet category |
Apollo asteroid, Earth-crosser asteroid |
||||||
| Epoch February 4, 2008 | |||||||
| Aphelion | 3.140 AU | ||||||
| Perihelion | 0.948 AU | ||||||
| Semi-major axis | 2.044 AU | ||||||
| Eccentricity | 0.536 | ||||||
| Orbital period | 2.92 a | ||||||
| Mean anomaly | 9.045° | ||||||
| Inclination | 5.628° | ||||||
| Longitude of ascending node | 127.095° | ||||||
| Argument of perihelion | 334.165° | ||||||
| Dimensions | ~250 meters[1] | ||||||
| Mass | <2.4×1010 kg[2] | ||||||
| Mean density | unknown | ||||||
| Equatorial escape velocity | <0.58 km/h[2] | ||||||
| Rotation period | roughly once per day[3] | ||||||
| Geometric albedo | 0.24 | ||||||
| Surface temp. Kelvin |
|
||||||
| Absolute magnitude (H) | 20.2 [4] | ||||||
Asteroid 2007 TU24 was discovered by the Catalina Sky Survey in Arizona on October 11, 2007. Imaging radar has estimated that it is 250 meters (820 ft) in diameter.[1] The asteroid passed 554,209 kilometer (344,370 mile or 1.4-lunar distance)[5] from Earth on January 29, 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 the asteroid 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.[1]
Contents |
[edit] Impact risk assessment
From the date of discovery of asteroid 2007 TU24 on 11 October 2007, a total of 316 observations of it had been made by 31 January 2008, spanning 112 days.[4] The trajectory is well defined. It was removed from the 'current impact risks' page of the NASA website on 4 December 2007 at 14:05 UTC.[7][8][9]
[edit] Further updates
Goldstone Observatory carried out radar observations on January 23 and January 24, 2008. As of January 24, the orbit of the asteroid was known with such a high precision that scientists were able to calculate close approaches from the year 67 AD to 2141 AD.[3] On January 29, 2008 at 08:33 UTC, 2007 TU24 passed by the earth at a nominal distance of 0.0037043 AU (554,160 km; 344,340 mi) with a relative speed of 9.248 km/s.[10]
Observations from Arecibo Observatory were taken on February 1–4.[1]
[edit] Other close approaches
- Asteroid 2004 XP14 was the closest potentially hazardous asteroid, passing Earth by 432,308 km (268,624 mi), 0.00289 AU, or just 1.1 times the Moon's average distance from Earth on July 3, 2006.
- Asteroid 4179 Toutatis (4.5 km diameter) came within 1.5 million km, 0.0104 AU (within 4 lunar distances) of the Earth on September 29, 2004.
- On August 7, 2027, (137108) 1999 AN10 will pass within 388,960 km (0.0026 AU) of the Earth.
- On Friday, April 13, 2029, Apophis will pass the earth within the orbits of the geosynchronous communication satellites.
[edit] See also
- List of notable asteroids
- Asteroid deflection strategies
- Asteroid naming conventions
- Radar astronomy
[edit] References
- ^ a b c d "NASA Scientists Get First Images of Earth Flyby Asteroid". NASA/JPL. 2008-01-25. http://www.jpl.nasa.gov/news/news.cfm?release=2008-014. Retrieved 2008-01-26.
- ^ a b radius of 0.125 km; volume of a sphere * maximum likely density of 3g/cm³ (though it could be a loose rubble pile) yields an improbable mass of 2.45e10 kg and an improbable escape velocity of 0.58 km/h.
- ^ a b 2007 TU24planning.html
- ^ a b JPL Small-Body Database Browser
- ^ "Asteroid Zooms by Earth". NASA/JPL. 2008-01-29. http://www.jpl.nasa.gov/news/news.cfm?release=2008-014a. Retrieved 2008-01-30.
- ^ Near-Earth Asteroid 2007 TU24 to Pass Close to Earth on Jan. 29 - Should be Observable with Modest Sized Telescopes
- ^ NEOs Removed from Impact Risks Tables
- ^ Current Impact Risks
- ^ Impact Risk Assessment: An Introduction
- ^ "JPL Close-Approach Data: (2007 TU24)". 2010-10-08 last obs (arc=2.99 years). http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007TU24;cad=1#cad. Retrieved 2011-11-09.
[edit] External links
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- Asteroid to Make Rare Close Flyby of Earth (Catalina Sky Survey Photo)
- Huge asteroid to fly by past earth.Independent Online
- Asteroid 2007 TU24: No Danger to Earth (Phil Plait January 25th, 2008)
- NEODys site entry for 2007TU24
|
||||||||||||||||||||||
