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Mu Ursae Majoris (Mu UMa, μ Ursae Majoris, μ UMa) is a star in the constellation Ursa Major. An apparent visual magnitude of +3.06〔 places it among the brighter members of the constellation. Parallax measurements give an estimated distance of roughly from Earth, with a margin of error of 4%.〔 This star has the proper name Tania Australis (formerly ''Tania australis''〔) Mu Ursae Majoris is an evolved star that is currently in the red giant stage with a stellar classification of M0 IIIab.〔 It has expanded to 75〔 times the radius of the Sun whilst the outer atmosphere has cooled to an effective temperature of 3,899 K,〔 giving it the orange-red hued glow of an M-type star.〔 Estimates of the luminosity range from 977〔–1,200〔 times that of the Sun. It is classified as a semiregular variable star and its brightness varies from magnitude 2.99m to 3.33m. This is a spectroscopic binary star system with a companion a mere 1.5 AU from the primary with an orbital period of 230 days.〔 ==Name and etymology== *The traditional name ''Tania (share with λ UMa) comes from the Arabic phrase "the Second Spring (of the Gazelle)".〔(Richard Hinckley Allen :Star Names — Their Lore and Meaning - Ursa Major, the Greater Bear )〕 The term ''Australis'' meaning "the south side" in Latin. *In Chinese, (), meaning ''Three Steps'', refers to an asterism consisting of μ Ursae Majoris, ι Ursae Majoris, κ Ursae Majoris, λ Ursae Majoris, ν Ursae Majoris and ξ Ursae Majoris. Consequently, μ Ursae Majoris itself is known as (, (英語:the Fourth Star of Three Steps)) and (, (英語:Star of Second Middle Step)).〔 ((Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 21 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「Mu Ursae Majoris」の詳細全文を読む スポンサード リンク
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