打开主菜单

天市左垣八巨蛇座η),也稱為東海,是在88星座巨蛇座中的一顆恆星。比較特別是它位於尾部,視星等為3.26等[2],是巨蛇座的第二亮星,肉眼就可以看見。視差測量估計它與地球的距離是60.5光年(18.5秒差距[1]

天市左垣八(東海,巨蛇座η)
Diagram showing star positions and boundaries of the Serpens constellation and its surroundings
Cercle rouge 100%.svg

東海(巨蛇座η)的位置(紅圈標示)。
觀測資料
曆元 J2000
星座 巨蛇座
星官
赤經 18h 21m 18.60056s[1]
赤緯 –02° 53′ 55.7766″[1]
視星等(V) 3.260[2]
特性
光谱分类K0 III-IV[3]
U−B 色指数+0.643[2]
B−V 色指数+0.940[2]
天体测定
徑向速度 (Rv)+8.4[4] km/s
自行 (μ) 赤经:–547.75[1] mas/yr
赤纬:–701.42[1] mas/yr
视差 (π)53.93 ± 0.18[1] mas
距离60.5 ± 0.2 ly
(18.54 ± 0.06 pc)
绝对星等 (MV)+1.87[5]
詳細資料
質量2.0[6] M
半徑5.897 ± 0.028[7] R
表面重力 (log g)3.21[3]
亮度19 ± 1[8] L
溫度4,890[3] K
金属量 [Fe/H]–0.42[3] dex
自轉速度 (v sin i)2.6[9] km/s
其他命名
58 Serpentis, BD−02° 4599, HD 168723, HIP 89962, HR 6869, SAO 142241.[10]
參考資料庫
SIMBAD data


這顆恆星比太陽大,質量為太陽的2倍,直徑是太陽的6倍[6][7]光譜分類的K0 III-IV吻合[3]光度分類對應於恆星演化階段的次巨星巨星。膨脹的恆星外層光度在有效溫度4,890K是太陽的19倍[3]。在這個溫度下,它有典型的K型恆星的橙色色調[11]。它有週期為0.09日的類太陽震盪英语solar-like oscillations [12]

天市左垣八以前被歸類為碳星,這使它成為天空中最亮的碳星但目前已經知道這種分類是錯誤的[13]

天市左垣八目前距離葛利斯710只有1.6光年[來源請求]

名稱编辑

中國,這顆恆星屬於星官天市左垣Tiān Shì Zuǒ Yuán),意思是天上市場左邊的城牆,也是中國舊有的11個諸侯屬地之一。天市左垣包含的恆星有巨蛇座η武仙座δ武仙座λ武仙座μ武仙座ο武仙座112蛇夫座η寶瓶座ζ巨蛇座θ1蛇夫座ν蛇夫座ξ [14]。因此,它也稱為天市左垣八 (Tiān Shì Zuǒ Yuán bā,意思是天上市場左側第八顆恆星,對應於東海的地區[15][16],可能就是指中國的東海 [來源請求]

參考資料编辑

  1. ^ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752, doi:10.1051/0004-6361:20078357 
  2. ^ 2.0 2.1 2.2 2.3 Cousins, A. W. J., Standardization of Broadband Photometry of Equatorial Standards, South African Astronomical Observatory Circulars, 1984, 8: 59, Bibcode:1984SAAOC...8...59C 
  3. ^ 3.0 3.1 3.2 3.3 3.4 3.5 Frasca, A.; 等, REM near-IR and optical photometric monitoring of pre-main sequence stars in Orion. Rotation periods and starspot parameters, Astronomy and Astrophysics, December 2009, 508 (3): 1313–1330, Bibcode:2009A&A...508.1313F, arXiv:0911.0760, doi:10.1051/0004-6361/200913327 
  4. ^ Wielen, R.; 等, Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, 1999, Bibcode:1999VeARI..35....1W 
  5. ^ Carney, Bruce W.; 等, Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars, The Astronomical Journal, March 2008, 135 (3): 892–906, Bibcode:2008AJ....135..892C, arXiv:0711.4984, doi:10.1088/0004-6256/135/3/892 
  6. ^ 6.0 6.1 Edvardsson, B., Spectroscopic surface gravities and chemical compositions for 8 nearby single sub-giants, Astronomy and Astrophysics, January 1988, 190 (1-2): 148–166, Bibcode:1988A&A...190..148E 
  7. ^ 7.0 7.1 Mérand, A.; 等, Interferometric radius and limb darkening of the asteroseismic red giant η Serpentis with the CHARA Array, Astronomy and Astrophysics, July 2010, 517: A64, Bibcode:2010A&A...517A..64M, doi:10.1051/0004-6361/200912103 
  8. ^ Piau, L.; 等, Surface convection and red-giant radius measurements, Astronomy and Astrophysics, February 2011, 526: A100, Bibcode:2011A&A...526A.100P, arXiv:1010.3649, doi:10.1051/0004-6361/201014442 
  9. ^ Massarotti, Alessandro; 等, Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity, The Astronomical Journal, January 2008, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209 
  10. ^ eta Ser -- Variable Star, SIMBAD (Centre de Données astronomiques de Strasbourg), [2012-01-19] 
  11. ^ The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004 [2012-01-16], (原始内容存档于2012-03-10) 
  12. ^ Tabur, V.; 等, Period-luminosity relations of pulsating M giants in the solar neighbourhood and the Magellanic Clouds, Monthly Notices of the Royal Astronomical Society, December 2010, 409 (2): 777–788, Bibcode:2010MNRAS.409..777T, arXiv:1007.2974, doi:10.1111/j.1365-2966.2010.17341.x 
  13. ^ Antipova, L. I.; Boyarchuk, A. A. The chemical composition of the red giant η Ser. Astronomy Reports. 2001, 45 (9): 700. Bibcode:2001ARep...45..700A. doi:10.1134/1.1398919. 
  14. ^ (中文) 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.
  15. ^ (中文) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 23 日
  16. ^ (中文) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name 互联网档案馆存檔,存档日期August 10, 2010,., Hong Kong Space Museum. Accessed on line November 23, 2010.