|
Delta Hydrae (δ Hya, δ Hydrae) is a Class A1, fourth-magnitude star in the constellation Hydra. Delta Hydrae is a binary double star, located about 180 light-years from Earth. It has 2.2 times the mass of the Sun, 1.5 times the Sun's radius and is radiating 17 times the luminosity of the Sun.〔 ==Name and etymology== In the catalogue of stars in the ''Calendarium of Al Achsasi Al Mouakket'', this star was designated Lisan al Shudja, which was translated into Latin as Lingua Hydri, meaning ''the snake's tongue''.〔 This star, along with ε Hya, ζ Hya, η Hya, ρ Hya and σ Hya (Minhar al Shija), were Ulugh Beg's Min al Azʽal, "Belonging to the Uninhabited Spot".〔 According to the catalogue of stars in the ''Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars'', ''Min al Azʽal'' or Minazal were the title for five stars :δ Hya as ''Minazal I'', η Hya as ''Minazal II'', ε Hya as ''Minazal III'', ρ Hya as ''Minazal IV'' and ζ Hya as ''Minazal V'' (exclude σ Hya)〔(Jack W. Rhoads - ''Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars'', Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971 )〕 In Chinese, (), meaning ''Willow (asterism)'', refers to an asterism consisting of δ Hydrae, σ Hydrae, η Hydrae, ρ Hydrae, ε Hydrae, ζ Hydrae, ω Hydrae and θ Hydrae〔 ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.〕 Consequently, δ Hydrae itself is known as (, (英語:the First Star of Willow).)〔 (AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 28 日 )〕 The people of Groote Eylandt called Unwala, "The Crab", for the star cluster including this star, ε Hya, ζ Hya, η Hya, ρ Hya and σ Hya (Minhar al Shija).〔Helaine Selin, ed., ''Encyclopaedia of the history of science, technology, and medicine in non-western cultures'', Dordrecht, Kluwer Academic Publishers, 1997, (p.105 ).〕 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「Delta Hydrae」の詳細全文を読む スポンサード リンク
|