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Xi Piscium (Xi Psc, ξ Piscium, ξ Psc) is a spectroscopic binary star system〔 in the constellation of Pisces, with an apparent magnitude of +4.61. The primary component is an orange K-type giant. It is approximately 179 light years from Earth. In 1690, the astronomer Johannes Hevelius in his ''Firmamentum Sobiescianum'' regarded the constellation Pisces as being composed of four subdivisions. Xi Piscium was considered to be part of the ''Linum Austrinum'', the South Cord.〔Hevelius, J., (1690) ''Firmamentum Sobiescianum'', Leipzig, Fig.NN〕 The spectroscopic binary nature of this star was discovered in 1901 by William Wallace Campbell using the Mills spectrograph at the Lick Observatory.〔 Xi Piscium is moving through the Galaxy at a speed of 30.7 km/s relative to the Sun. Its projected Galactic orbit carries it between 24,100 and 39,700 light years from the center of the Galaxy.〔(Xi Piscium (HIP 8833) )〕 Xi Piscium came closest to the Sun 1.8 million years ago when it had brightened to magnitude 1.77 from a distance of 51 light years.〔 ==In non-Western astronomy== In Chinese astronomy, the "Outer Fence" () refers to an asterism consisting of ξ Piscium, δ Piscium, ε Piscium, ζ Piscium, μ Piscium, ν Piscium and α Piscium. Consequently, ξ Piscium itself is known as the "Sixth Star of the Outer Fence" ()〔 ( AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日 )〕 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「Xi Piscium」の詳細全文を読む スポンサード リンク
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