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The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, the first asteroid of this group which was discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crosser asteroids that have orbital semi-major axis greater than that of the Earth (> 1 AU) but perihelion distances less than the Earth's aphelion distance (q < 1.017 AU). , the Apollo asteroid group includes a total of 6,923 known asteroids〔 of which 991 are currently numbered.〔 Asteroids are not numbered until they have been observed at two or more oppositions. More than a thousand Apollo asteroids are large enough and may get close enough to Earth to be known as potentially hazardous asteroids.〔 The closer their semi-major axis is to Earth's, the less eccentricity is needed for the orbits to cross. The February 15, 2013 Chelyabinsk meteor that exploded over the city of Chelyabinsk in the southern Urals region of Russia, injuring an estimated one thousand people with flying glass from broken windows, was an Apollo class asteroid.〔http://www.newscientist.com/article/dn23213-russian-meteor-traced-to-apollo-asteroid-family.html〕 The largest known Apollo asteroid is 1866 Sisyphus, with a diameter of about 8.5 km. Examples of known Apollo asteroids include: == See also == * * Apollo asteroid records 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「List of Apollo asteroids」の詳細全文を読む スポンサード リンク
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