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Leo II (or Leo B) is a dwarf spheroidal galaxy about 690,000 light-years away in the constellation Leo. As of October 2008 it is one of 24 known satellite galaxies of the Milky Way.〔 〕 As of 2007 Leo II is thought to have a core radius of 178 ± 13 pc and a tidal radius of 632 ± 32 pc.〔 〕 It was discovered in 1950 by Robert George Harrington and Albert George Wilson, from the Mount Wilson and Palomar Observatories in California. ==Recent Findings== In 2007 a team of 15 scientists observed Leo II through the 8.2 meter Subaru optical-infrared telescope in Mauna Kea, Hawaii. Over 2 nights, 90 minutes of exposures were taken and 82,252 stars were detected down to a visible magnitude of 26. They found that Leo II consists largely of metal-poor older stars, a sign that it has survived the galactic cannibalism under which massive galaxies (e.g., the Milky Way) consume smaller galaxies to attain their extensive size.〔 〕 Observation at ESO estimates Leo II's mass to be (2.7 ± 0.5)×107 M⊙.〔 〕 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「Leo II (dwarf galaxy)」の詳細全文を読む スポンサード リンク
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