大犬座ι

天狼增五（Iota Canis Majoris）的拉丁化源自ι Canis Majoris，孤独的^[12]位在南天星座的大犬座，是一颗超巨星变星。它的视星等在+4.36和+4.40之间变化著^[3]。根据视差的测量，这颗恒星与地球相距约3,100光年。它正以+41.2Km/s的径向速度远离而去^[7]。

天狼增五（大犬座ι）

天狼增五在大犬座的位置（红圈）。
观测资料 历元 J2000
星座	大犬座
星官	天狼 （井宿）
赤经	06h 56m 08.22413s[1]
赤纬	−17° 03′ 15.2675″[1]
视星等（V）	4.40[2] (4.36 - 4.40[3])
特性
光谱分类	B3Ib[4]，或B3Ib/II[5]
U−B 色指数	−0.74[6]
B−V 色指数	−0.07[6]
变星类型	仙王座β型?[2]
天体测定
径向速度 (Rv)	+41.20[7] km/s
自行 (μ)	赤经：−3.56 ± 0.17[1] mas/yr 赤纬：+2.42 ±0.20[1] mas/yr
视差 (π)	1.04 ± 0.20[1] mas
距离	approx. 3,100 ly (approx. 1,000 pc)
绝对星等 (MV)	−5.51[8]
详细资料
质量	12.5[9] M☉
半径	25.9[8] R☉
表面重力 (log g)	2.60[10]
亮度	47,000[8] L☉
温度	17,000[10] K
金属量 [Fe/H]	−0.17[11] dex
自转速度 (v sin i)	7001270000000000000♠27±4[10] km/s
年龄	14.8[9] Myr
其他命名
ι CMa、​20 Canis Majoris、​BD−16°1661、​FK5 2536、​GC 9107、​HD 51309、​HIP 33347、​HR 2596、​SAO 152126
参考数据库
SIMBAD	资料

天狼增五是一颗大质量的蓝白色B型超巨星，光谱类型为B3Ib^[4]。它被归类为仙王座β型变星^[3]，但超巨星光谱类型和一个多月的期意味着它不再被认为是这种类型的^[2]。这颗恒星的年龄为1,480万，并正以27Km/s投影旋转速度自转^[10]。它的质量是太阳的12.5倍^[9]，半径是太阳的25.9倍^[8]。天狼增五的光度是太阳的47,000倍^[8]，光球层的有效温度是17,000K^[10]。

这颗恒星在与星际物质的相互作用中显示出弓形激波特征，但这种星云与恒星在银河系中的运动不一致^[13]。

参考资料

1. van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, S2CID 18759600, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357
2. Stankov, Anamarija; Handler, Gerald. Catalog of Galactic β Cephei Stars. The Astrophysical Journal Supplement Series. 2005, 158 (2): 193–216. Bibcode:2005ApJS..158..193S. ISSN 0067-0049. S2CID 119526948. arXiv:astro-ph/0506495 . doi:10.1086/429408.
3. Samus, N. N.; Durlevich, O. V.; et al. VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013). VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 2009, 1: 02025. Bibcode:2009yCat....102025S.
4. Prinja, R. K.; Massa, D. L. Signature of wide-spread clumping in B supergiant winds. Astronomy and Astrophysics. 2010, 521: L55. Bibcode:2010A&A...521L..55P. ISSN 0004-6361. S2CID 59151633. arXiv:1007.2744 . doi:10.1051/0004-6361/201015252.
5. Houk, Nancy; Smith-Moore, M. Michigan catalogue of two-dimensional spectral types for the HD stars 4. Ann Arbor: Dept. of Astronomy, University of Michigan. 1978. Bibcode:1988mcts.book.....H.
6. Mermilliod, J.-C. Compilation of Eggen's UBV data, transformed to UBV (unpublished). Catalogue of Eggen's UBV Data. 1986. Bibcode:1986EgUBV........0M.
7. Gontcharov, G. A. Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system. Astronomy Letters. 2006, 32 (11): 759–771. Bibcode:2006AstL...32..759G. ISSN 1063-7737. S2CID 119231169. arXiv:1606.08053 . doi:10.1134/S1063773706110065.
8. Balona, L. A.; Engelbrecht, C. A. Photometry and frequency analysis of line profile variables. Monthly Notices of the Royal Astronomical Society. 1985, 214 (4): 559. Bibcode:1985MNRAS.214..559B. doi:10.1093/mnras/214.4.559 .
9. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun. Monthly Notices of the Royal Astronomical Society. 2011, 410: 190–200. Bibcode:2011MNRAS.410..190T. S2CID 118629873. arXiv:1007.4883 . doi:10.1111/j.1365-2966.2010.17434.x.
10. Lefever, K.; Puls, J.; Morel, T.; Aerts, C.; Decin, L.; Briquet, M. Spectroscopic determination of the fundamental parameters of 66 B-type stars in the field-of-view of the CoRoT satellite. Astronomy and Astrophysics. 2010, 515: A74. Bibcode:2010A&A...515A..74L. S2CID 54028925. arXiv:0910.2851 . doi:10.1051/0004-6361/200911956.
11. Gies, Douglas R.; Lambert, David L. Carbon, nitrogen, and oxygen abundances in early B-type stars. Astrophysical Journal. 1992, 387: 673. Bibcode:1992ApJ...387..673G. doi:10.1086/171116.
12. Eggleton, P. P.; Tokovinin, A. A. A catalogue of multiplicity among bright stellar systems. Monthly Notices of the Royal Astronomical Society. September 2008, 389 (2): 869–879. Bibcode:2008MNRAS.389..869E. S2CID 14878976. arXiv:0806.2878 . doi:10.1111/j.1365-2966.2008.13596.x.
13. Bodensteiner, J.; Baade, D.; Greiner, J.; Langer, N. Infrared nebulae around bright massive stars as indicators for binary interactions. Astronomy & Astrophysics. October 2018, 618: 13. Bibcode:2018A&A...618A.110B. S2CID 118972162. arXiv:1806.01294 . doi:10.1051/0004-6361/201832722. A110.