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Comet 81P/Wild, also known as Wild 2 (pronounced "vilt two") ( ), is a comet named after Swiss astronomer Paul Wild, who discovered it on January 6, 1978, using a 40-cm Schmidt telescope at Zimmerwald, Switzerland. For most of its 4.5 billion-year lifetime, Wild 2 probably had a more distant and circular orbit. In September 1974, it passed within one million kilometers of the planet Jupiter, whose strong gravitational pull perturbed the comet's orbit and brought it into the inner Solar System.〔 ((Cometography Home Page ))〕 Its orbital period changed from 43 years to about 6 years,〔 and its perihelion is now about 1.59 astronomical unit (AU).〔(【引用サイトリンク】url=http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=0081P )〕 == Nucleus parameters == * Dimensions: * Density: * Mass: 〔Using the volume of an ellipsoid of 5.5×4.0×3.3 km * a rubble pile density of 0.6 g/cm³ yields a mass (m=d *v) of 2.28 kg〕 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「81P/Wild」の詳細全文を読む スポンサード リンク
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