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HAT-P-11b (or Kepler-3b) is an extrasolar planet orbiting the star HAT-P-11. This planet was discovered by the transit method and submitted for publication on 2 January 2009. This planet is located approximately away〔 in the constellation of Cygnus, orbiting the 10th magnitude K-type star HAT-P-11. This planet was the smallest transiting planet known when first discovered, with a radius about 5 times that of Earth; but is more massive than Gliese 436 b at a true mass of 26 times that of Earth. This planet orbits about the same distance from the star as 51 Pegasi b is from 51 Pegasi, typical of transiting planets. However, the orbit of this planet is eccentric, at around 0.198, unusually high for hot Neptunes. HAT-P-11b's orbit is also highly inclined, with a tilt of approximately 103 degrees relative to its star's rotation.〔(【引用サイトリンク】 title=Inclined Orbits Prevail in Exoplanetary Systems )〕 The HAT-P-11 system was within the field of view of the Kepler spacecraft.〔 Its radial velocity is drifting and this may be a result of an as-yet-undiscovered planet in the system.〔 The planet fits models for 90% heavy elements. Expected temperature is 878 ± 15K.〔 Actual temperature must await calculations of secondary transit. On 24 September 2014, NASA reported that HAT-P-11b is the first Neptune-sized exoplanet known to have a relatively cloud-free atmosphere and, as well, the first time molecules, namely water vapor, of any kind have been found on such a relatively small exoplanet. ==See also== * Gliese 436 b * HATNet Project * HAT-P-7b * Kepler Mission 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「HAT-P-11b」の詳細全文を読む スポンサード リンク
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