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Epsilon Carinae (ε Car, ε Carinae) is a star in the southern constellation of Carina. It is also known by the name Avior. At apparent magnitude +1.86 it is one of the brightest stars in the night sky, but is not visible from the northern hemisphere. Epsilon Carinae is a double star located roughly away from the Earth.〔 Measurements during the Hipparcos mission give the pair an angular separation of 0.46 arcseconds with a difference in magnitude of 2.0.〔 At their estimated distance, this angle is equivalent to a physical separation of around 4 Astronomical Units.〔 This pair may form an eclipsing binary system〔 with a period of 785 days (2.15 years), resulting in a magnitude change of 0.12 during each eclipse.〔〔 The primary component has an apparent visual magnitude of 2.2,〔 which by itself would still make it the third brightest star in the constellation. It is an evolved giant star with a stellar classification of K0 III. However, examination of the ultraviolet flux from this star suggests it may instead be of spectral type K7.〔 The fainter secondary companion has an apparent visual magnitude of 4.1,〔 which, if it were a solitary star, would be bright enough to be seen with the naked eye. This is a hot, core hydrogen-fusing B-type main sequence star of spectral class B2 Vp.〔 The secondary may itself have an orbiting stellar companion of spectral class F8:.〔 ==Etymology== The name Avior is not classical in origin. It was assigned to the star by Her Majesty's Nautical Almanac Office in the late 1930s during the creation of The Air Almanac, a navigational almanac for the Royal Air Force. Of the fifty-seven navigation stars included in the new almanac, two had no classical names: Epsilon Carinae and Alpha Pavonis. The RAF insisted that all of the stars must have names, so new names were invented. Alpha Pavonis was named "Peacock", a translation of Pavo, whilst Epsilon Carinae was called "Avior".〔 In Chinese, (), meaning ''Sea Rock'', refers to an asterism consisting of ε Carinae, ι Carinae, HD 83183, HD 84810 and υ Carinae .〔 ''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, ε Carinae itself is known as (, (英語:the First Star of Sea Rock).)〔 (香港太空館 - 研究資源 - 亮星中英對照表 ), Hong Kong Space Museum. Accessed on line November 23, 2010.〕 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「Epsilon Carinae」の詳細全文を読む スポンサード リンク
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