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Gliese 1214 is a dim M4.5〔 red dwarf in the constellation Ophiuchus with an apparent magnitude of 14.7.〔 It is located at a distance of approximately 47 light years from Earth.〔 It is about one-fifth as large as the Sun〔 with a surface temperature estimated to be .〔 Its luminosity is only 0.003% that of the Sun.〔 The estimate for the stellar radius is 15% larger than predicted by theoretical models.〔 It also shows a 1% intrinsic variability in the near-infrared probably caused by stellar spots.〔 ==Planetary system== In mid-December 2009, a team of Harvard-Smithsonian astronomers announced the discovery of a companion extrasolar planet, Gliese 1214 b, potentially composed largely of water and having the mass and diameter of a super-Earth.〔〔 Discovered by the MEarth project and investigated further by the HARPS spectrograph on ESO’s 3.6-metre telescope at La Silla, GJ 1214 b is the second super-Earth exoplanet for which astronomers have determined the mass and radius, giving vital clues about its structure. It is also the first super-Earth around which an atmosphere has been found. A search for additional planets using transit timing variations was negative.〔 No transit-time variations have yet been found for this transit. As of 2012, "the given data does not allow us to conclude that there is a () planet in the mass range 0.1–5 Earth-masses and the period range 0.76–1.23 or 1.91–3.18 days."〔 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「Gliese 1214」の詳細全文を読む スポンサード リンク
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