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弧矢二

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弧矢二(大犬座η)

弧矢二是顆藍色的超巨星,位於大犬座,相當於大犬的尾巴
觀測資料
曆元 J2000
星座 大犬座
星官
赤經 07h 24m 05.70228s[1]
赤緯 –29° 18′ 11.1798″[1]
視星等(V) 2.450[2]
特性
光谱分类B5 Ia[3]
U−B 色指数−0.708[2]
B−V 色指数−0.087[2]
变星类型α Cyg[4]
天体测定
徑向速度 (Rv)41.1[5] km/s
自行 (μ) 赤经:−4.14[1] mas/yr
赤纬:5.81[1] mas/yr
视差 (π)1.64 ± 0.40[1] mas
距离approx. 2,000 ly
(approx. 600 pc)
绝对星等 (MV)-7.0[6]
詳細資料
質量19.19 ± 1.15[7] M
半徑56.3[6] R
亮度105,442[7] L
溫度15,000[3] K
自轉速度 (v sin i)50[8] km/s
其他命名
Aludra, 31 Canis Majoris, CD −29° 4328, FK5 283, HD 58350, HIP 35904, HR 2827, SAO 173651.
參考資料庫
SIMBAD资料

弧矢二(η Cma,η Canis Majoris)位於星座大犬座。它的傳統名稱源自阿拉伯语عذرا al-‘aðrā,英文是Aludra。自1943年起,它的光譜被作為此類恆星光譜分類的參考標準之一[9]

阿拉伯عذرا al-‘aðrā的意思是"處女",弧矢七(大犬座ε)、弧矢一(大犬座δ)和軍市增五(大犬座ο2)在阿拉伯文中合稱為Al ʽAdhārāألعذاري[10]

中國屬於井宿下的星官弧矢Hú Shǐ),意思是弓和箭[11]。這個星官還包括弧矢一(大犬座δ)、弧矢三HD 63032)、HD 65456(弧矢四)、弧矢五(船尾座ο)、船尾座κ(弧矢六)、弧矢七(大犬座ε)、大犬座κ(弧矢八)和弧矢九(船尾座π)[12]

性質

弧矢二儘管離地球有一段距離,但因為它的本質(絕對星等)非常明亮,是太陽的許多倍,所以看起來依然很亮。它是顆藍白色的超巨星,光譜類型為B5Ia,光度是太陽的176,000倍,直徑約是太陽的80倍[13]。Hohle和他的同事利用視差消光和光譜分析,測出它的質量是太陽的19.19倍,亮度是太陽的105,442倍[7]。它的年齡還只是太陽的一部分,但已經在生命的最後階段。它還在繼續膨脹中,可能成為一顆紅巨星,但也可能已經通過這一階段。但無論是何種狀況,在未來的數百萬年它都將成為超新星

弧矢二是一顆天鵝座α型變星,它的亮度以4.7天的週期,在+2.38至+2.48等之間變化[4][14]

同名物

美國海軍有兩艘巨爵級貨船USS Aludra (AF-55)USS Aludra (AK-72),以這顆恆星命名。

參考資料

  1. ^ 1.0 1.1 1.2 1.3 1.4 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可免费查阅. doi:10.1051/0004-6361:20078357. 
  2. ^ 2.0 2.1 2.2 Alcaino, Gonzalo, The Globular Clusters NGC 2808 and NGC 1851, Astrophysical Journal, June 1969, 156: 853, Bibcode:1969ApJ...156..853A, doi:10.1086/150019 
  3. ^ 3.0 3.1 Prinja, R. K.; Massa, D. L., Signature of wide-spread clumping in B supergiant winds, Astronomy and Astrophysics, October 2010, 521: L55, Bibcode:2010A&A...521L..55P, arXiv:1007.2744可免费查阅, doi:10.1051/0004-6361/201015252 
  4. ^ 4.0 4.1 Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. The 74th Special Name-list of Variable Stars. Information Bulletin on Variable Stars. 1999, 4659: 1. Bibcode:1999IBVS.4659....1K. 
  5. ^ Wielen, R.; et al, Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Veröff. Astron. Rechen-Inst. Heidelb (Astronomisches Rechen-Institut Heidelberg), 1999, 35 (35): 1, Bibcode:1999VeARI..35....1W 
  6. ^ 6.0 6.1 Underhill, A. B.; et al, Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars, Monthly Notices of the Royal Astronomical Society, November 1979, 189 (3): 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601 
  7. ^ 7.0 7.1 7.2 Hohle, M. M.; Neuhäuser, R.; Schutz, B. F., Masses and luminosities of O- and B-type stars and red supergiants, Astronomische Nachrichten, April 2010, 331 (4): 349, Bibcode:2010AN....331..349H, arXiv:1003.2335可免费查阅, doi:10.1002/asna.200911355 
  8. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica, Rotational Velocities of B Stars, The Astrophysical Journal, July 2002, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590 
  9. ^ Garrison, R. F., Anchor Points for the MK System of Spectral Classification, Bulletin of the American Astronomical Society, December 1993, 25: 1319 [2012-02-04], Bibcode:1993AAS...183.1710G, (原始内容存档于2019-06-25) 
  10. ^ Allen, R. H., Star Names: Their Lore and Meaning Reprint, New York, NY: Dover Publications Inc: 130, 1963 [2010-12-12], ISBN 0-486-21079-0, (原始内容存档于2024-04-05) 
  11. ^ 弧矢 (Hú Shǐ) is westernized into Koo She. R.H. Allen had opinion that Koo She refers to the asterism including δ Velorum and ω Velorum. AEEA opinion is, δ Velorum is member of 天社 (Tiān Shè), meaning Celestial Earth God's Temple asterism and ω Velorum is not member of any asterisms. 天社 (Tiān Shè) is westernized into Tseen She and R.H.Allen used the term Tseen She for Chinese name of η Carinae. See Richard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navis and (中文) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日页面存档备份,存于互联网档案馆).
  12. ^ (中文) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日页面存档备份,存于互联网档案馆
  13. ^ Jerzykiewicz, M.; Molenda-Zakowicz, J. Empirical Luminosities and Radii of Early-Type Stars after Hipparcos (PDF). Acta Astronomica. 2000, 50: 369–80 [2016-01-16]. Bibcode:2000AcA....50..369J. (原始内容存档 (PDF)于2020-07-14). 
  14. ^ Watson, Christopher. Eta Canis Majoris. AAVSO Website. American Association of Variable Star Observers. 3 May 2013 [5 February 2014]. (原始内容存档于2014-02-22).