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, also written as (343158) 2009 HC82 is a near-Earth asteroid, initially listed as a potentially hazardous object.〔 It was removed from the Sentry Risk Table on 6 May 2009.〔(【引用サイトリンク】publisher=NASA/JPL Near-Earth Object Program Office )〕 It has a retrograde orbit and makes many close approaches to Earth, Venus, and Mars at a very high relative velocity. ==Velocity== has a retrograde orbit and thus orbits the Sun in the opposite direction of other objects. Therefore, close approaches to this object can have very high relative velocities. , it the highest relative velocity to Earth of objects that come within 0.5 AU of Earth.〔 (sorted by descending relative velocity, dist<0.5AU = "215,221 close-Earth approaches")〕 On 11 November 2024, will pass about from Earth, but with a record high relative velocity of about 282,900 km/h (78.58 km/s).〔(【引用サイトリンク】title=JPL Close-Approach Data: (2009 HC82) )〕 Both Halley's Comet (254,000 km/h)〔(【引用サイトリンク】title=JPL Close-Approach Data: 1P/Halley )〕 and 55P/Tempel-Tuttle (252,800 km/h)〔(【引用サイトリンク】title=JPL Close-Approach Data: 55P/Tempel-Tuttle )〕 have slightly lower relative velocities to Earth. On 2 February 2053, will pass about 0.08 AU from Venus.〔 On 22 October 2060, it may pass about from Mars.〔 The multiple planet crossing and retrograde orbit suggests that this object may be an extinct comet or damocloid asteroid similar to 5335 Damocles, , and 20461 Dioretsa. Since the true albedo is unknown and it has an absolute magnitude (H) of 16.1,〔 it is about 1.6 to 3.6 km in diameter.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「(343158) 2009 HC82」の詳細全文を読む スポンサード リンク
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