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＊ 地球接近小惑星 わずか約423万キロメートル ＊
2005 WJ56 was discovered by LINEAR on November 29, 2005. It will approach within 0.0279 AU (10.9 lunar distances) on January 10 when it will be a very strong radar target. Goldstone observations are scheduled on January 13 and Arecibo observations are scheduled on January 9-11. Note that Goldstone observations straddle the January 12-13 date boundary; we can start setting up late on Jan. 12 and begin transmitting at 01:15Z on Jan. 13 (5:15 PM, Saturday, January 12, Pacific Time). Given its absolute magnitude of 17.8, 2005 WJ56 has a diameter that is probably within a factor of two of 870 meters. Otherwise, we know nothing about its physical properties, but given recent experience, there's a ~1/6 chance that it's a binary object. This object will brighten to about 12th magnitude in mid-January when it will be a good target for photometric and spectroscopic observations. Due to its diameter and the proximity of its orbit to Earth, 2005 WJ56 has been classified as a "Potentially Hazardous Asteroid" by the Minor Planet Center. Orbital and Physical Characteristics orbit type Apollo semimajor axis 0.959 AU eccentricity 0.152 inclination 21.6° perihelion distance 0.813 AU aphelion distance 1.105 AU absolute magnitude (H) 17.8 diameter 870 meters +- a factor of two rotation period unknown pole direction unknown lightcurve amplitude unknown spectral class X (M. D. Hicks, personal communication) Last update: 2008 January 08 |
2008/01/09
