|
Eta Geminorum (η Gem, η Geminorum) is a triple star system in the constellation Gemini. It has the traditional names Tejat Prior, Propus (from the Greek, meaning forward foot) and Praepes and Pish Pai (from the Persian Pīshpāy, پیشپای, meaning foreleg).〔p. 235, Star-names and Their Meanings, Richard Hinckley Allen, G. E. Stechert, 1899.〕 This star, along with γ Gem (Alhena), μ Gem (Tejat Posterior), ν Gem and ξ Gem (Alzirr) were ''Al Han'ah'', "the brand" (on the neck of the camel). They also were associated in ''Al Nuḥātai'', the dual form of ''Al Nuḥāt'', "a Camel's Hump". In Chinese lunar mansion, Tejat Prior is the only member of the lunar mansion 钺 (Pinyin: Yuè, Chinese "Battle Axe").〔 (AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 26 日 )〕〔(Richard Hinckley Allen: Star Names — Their Lore and Meaning: Gemini )〕 ==Properties== Eta Geminorum A is a spectroscopic binary. The primary is a semiregular variable star of type SRA whose brightness changes with a period of 234 days between magnitude +3.15 and +3.9. It is located 350 light years from the Sun and is a red giant of the spectral type M3. The secondary, probably a class B, orbits with a period of 8.2 years. Eta Geminorum B, a class G dwarf, orbits the pair with a period of at least 700 years.〔(The Spectrographic Orbit and Light-Variations of η Geminorum ), Dean B. McLaughlin and Suzanne E. A. van Dijke, ''Astrophysical Journal'' 100 (July 1944), pp. 63–68.〕,〔(Eta Geminorum ) at Jim Kaler's STARS.〕 Eta Geminorum is near the ecliptic, so it can be occulted by the Moon and, very rarely, by planets. The last occultation by a planet took place on July 27, 1910, by Venus, and the next to last on July 11, 1837, by Mercury. 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「Eta Geminorum」の詳細全文を読む スポンサード リンク
|