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Alpha Ceti (α Cet, α Ceti) is a star in the constellation of Cetus. It has the traditional name Menkar or Menkab. The name Menkar derives from the Arabic word منخر ''manħar'' "nostril" (of Cetus). This star, along with γ Cet (Kaffaljidhma), δ Cet, λ Cet (Menkar), μ Cet, ξ1 Cet and ξ2 Cet were ''Al Kaff al Jidhmah'', "the Part of a Hand".〔(Star Name - R.H. Allen p.160 )〕 In Chinese, (), meaning ''Circular Celestial Granary'', refers to an asterism consisting of α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, α Ceti itself is known as (, (英語:the First Star of Circular Celestial Granary).)〔 (AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日 )〕 ==Structure== Despite having the Bayer designation α Ceti, at visual magnitude 2.54 this star is actually not the brightest star in the constellation Cetus. That honor goes instead to Beta Ceti at magnitude 2.04. Menkar is a red giant with a stellar classification of M1.5 IIIa. It has more than twice the mass of the Sun and, as a giant star has expanded to about 89 times the Sun's radius. The large area of the photosphere means that it is emitting about 1,455 times as much energy as the Sun, even though the effective temperature is only 3,795 K (compared to 5,778 K on the Sun). The relatively low temperature gives Menkar the red hue of an M-type star.〔 Menkar has evolved from the main sequence after exhausting the helium at its core. As it begins to burn its carbon core it will probably become a highly unstable star like Mira before finally shedding its outer layers and forming a planetary nebula, leaving a relatively large white dwarf remnant.〔 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「Alpha Ceti」の詳細全文を読む スポンサード リンク
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