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\right)〕 }} =6.63 and the absolute visual magnitude of the Sun 〕 | temperature = 4977 ± 59〔 | metal_fe = −0.31 ± 0.03〔 | rotation = ~48 days〔 | rotational_velocity = 3〔 | age_gyr = 1.2 (≥ 0.2)〔 }} HD 40307 is an orange (K-type) main-sequence star located approximately 42 light-years away in the constellation of Pictor (the Easel), taking its primary name from its Henry Draper Catalogue designation. It is calculated to be slightly less massive than the Sun. HD 40307 was observed during or before 1900 as part of the Cape Photographic Durchmusterung.〔(CPD−60 508 ), database entry, Cape Photographic Durchmusterung (CPD), D. Gill and J. C. Kapetyn, 1895–1900, CDS ID (I/108 ).〕 The star has six known planets, three discovered in 2008〔〔(Three super-Earths found around one star ), Jeanna Bryner, MSNBC, June 16, 2008. Accessed on line June 18, 2008.〕 and three more in 2012. One of them, HD 40307 g, is a potential super-Earth in the habitable zone, with an orbital period of about 200 days. This object might be capable of supporting liquid water on its surface, although much more information must be acquired before its habitability can be assessed.〔(Possible Earth-like planet could hold water; scientists cautious ), Amina Khan, Los Angeles Times, November 7, 2012. Accessed on line November 8, 2012.〕 == History and nomenclature == The designation ''HD 40307'' is from the Henry Draper Catalogue, which is based on spectral classifications made between 1911 and 1915 by Annie Jump Cannon and her co-workers, and was published between 1918 and 1924.〔pp. 214–215 in The Henry Draper Memorial, Annie J. Cannon, ''Journal of the Royal Astronomical Society of Canada'' 9, #5 (May–June 1915), pp. 203–215, .〕〔The Henry Draper Catalogue, Annie J. Cannon and Edward C. Pickering, ''Annals of Harvard College Observatory''; hours 0 to 3, 91 (1918), ; hours 4 to 6, 92 (1918), ; hours 7 to 8, 93 (1919), ; hours 9 to 11, 94 (1919), ; hours 12 to 14, 95 (1920), ; hours 15 to 16, 96 (1921), ; hours 17 to 18, 97 (1922), ; hours 19 to 20, 98 (1923), ; hours 21 to 23, 99 (1924), .〕 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「HD 40307」の詳細全文を読む スポンサード リンク
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