|
HIP 57050 (GJ 1148 / LHS 2443 / G 122-40 / Ross 1003) is an M-type star 36 light-years from the Sun with a planetary companion HIP 57050 b.〔〔Louise Good, (Planet Detected in Habitable Zone of Nearby Star ), ''Na Kilo Hoku "The Ones Who Look to the Stars"'', A Newsletter from the Institute of Astronomy, University of Hawai'i, No. 35, 2010.〕 HIP 57050 has a metallicity twice that of the Sun and among the highest in the immediate Solar neighborhood.〔Nader Haghighipour, Steven S. Vogt, R. Paul Butler, Eugenio J. Rivera, Greg Laughlin, Stefano Meschiari, Gregory W. Henry, (The Lick-Carnegie Exoplanet Survey: A Saturn-Mass Planet in the Habitable Zone of the Nearby M4V Star HIP 57050 ), ''The Astrophysical Journal'' 715 (2010) 271.〕 ==HIP 57050 b== A team led by astronomer Nader Haghighipour reported the discovery of a Saturn-sized planet in the habitable zone of the star in 2010. According to Haghighipour. the detection is important because it "indicates that observational techniques are on the right track for finding habitable low-mass rocky planets similar to Earth."〔 According to its discoverers, HIP 57050 b provides support for the proposition that planet-bearing M-class stars tend to be metal-rich, a correlation already observed in F, G and K-class stars.〔 At the expected planetary effective temperature, the atmosphere may contain water clouds, potentially detectable by the Hubble Space Telescope if it could capture a planetary transit.〔 The planet's discoverers speculated about the possibility of a habitable moon: ::"By analogy with our own solar system, whose gas giants all have dozens of moons, one might expect HIP 57050 b to also harbor such moons. In our solar system, ∼0.02% of the masses of the gas giants are assigned to their satellites. This would translate to a satellite with ∼2% of Earth's mass (similar to Titan) orbiting HIP 57050 b. While it is not out of the question that HIP 57050 b could harbor a moon, and that moon would thus be in the liquid water HZ of the parent star, an object with only 1/5th of the mass of Mars in the liquid water HZ is probably not a particularly good prospect for habitability from various standpoints. In any case, direct detection of such a moon would be extremely challenging."〔 Paul Gilster of the Tau Zero Foundation has commented: :"Based on our knowledge of the gas giants in our own Solar System, it’s a natural supposition that this is a world with moons, and if so, their location in the habitable zone draws inevitable comparisons with fictional worlds like Pandora."〔Paul Gilster, (Warm ‘Saturns’ and Their Moons ), ''Centauri Dreams'', 11 May 2010.〕 Gilster suggested that an Earth-sized moon could exist around the planet if it were captured after forming independently.〔 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「HIP 57050」の詳細全文を読む スポンサード リンク
|