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Delta Serpentis (δ Serpentis, δ Ser) is a star system in the constellation Serpens, in its head (Serpens Caput). It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of ''al-Nasaqān'' "the Two Lines"., along with α Ser (Unukalhai), ε Ser (Ba, Pa), δ Oph (Yed Prior), ε Oph (Yed Posterior), ζ Oph (Han) and γ Oph (Tsung Ching). According to the catalogue of stars in the ''Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars'', ''al-Nasaq al-Yamānī'' or Nasak Yamani were the title for two stars :δ Ser as ''Nasak Yamani I'' and ε Ser as ''Nasak Yamani II'' (exclude α Ser, δ Oph, ε Oph, ζ Oph and γ Oph)〔(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 ''Right Wall of Heavenly Market Enclosure'', refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of δ Serpentis, β Herculis, γ Herculis, κ Herculis, γ Serpentis, β Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.〔 ''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 Serpentis itself is known as (, (英語:the Sixth Star of Right Wall of Heavenly Market Enclosure)), represent the state Qin (秦) (or Tsin),〔(Star Names - R.H.Allen p.376 )〕〔 (AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 24 日 )〕〔 (English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name ), Hong Kong Space Museum. Accessed on line November 23, 2010.〕 together with θ Capricorni and 30 Capricorni in ''Twelve States'' (asterism).〔(Star Names - R.H.Allen p.142 )〕 ==Properties== It is approximately 210 light years from Earth. The light from the four stars in the system give a combined apparent magnitude of +3.80. The system consists of a pair of binary stars separated by 66 arcseconds. The primary component, Delta Serpentis A, is a yellow-white F-type subgiant with an apparent magnitude of +4.2. It is classified as a Delta Scuti type variable star and its magnitude varies by 0.04 with a period of 0.134 days. Its binary companion, Delta Serpentis B, is also a F-type subgiant which is slightly dimmer, with a magnitude of +5.2. A and B are separated by four arcseconds on the sky, and perform one orbit around their centre of mass once every 3200 years. The 14th magnitude stars Delta Serpentis C and 15th magnitude Delta Serpentis D form the second binary sub-system. They are separated from each other by 4.4 arcseconds. 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 Serpentis」の詳細全文を読む スポンサード リンク
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