天鹅座α型变星

天鹅座α型变星是显示出非径向脉动的变星,意味着当恒星表面有些地方收缩时,而同时也有些地方是扩张的[1]。它们是光谱类型B或A的超巨星,亮度变化在0.1视星等,并与脉动相关联,而由于和多脉动周期的节拍相关联,因而通常是不规则变星。脉冲周期通常有几天到几个星期的周期。

这种变星的原型是天津四(天鹅座α),显示的亮度在1.21 和 +1.29 之间波动。众所周知很多在早期的超巨星都有小幅快速的变动,但之前它们未被归为一类,直到1985年的变星总表第四版才收录为变星的一种,缩写的字母为ACYG(Alpha Cygni variable stars)[2]。许多高光度蓝变星(LBVs)在它们平静(热)阶段显示出天鹅座α型变星的型态,但在这种情况下一般仍使用LBV的分类。

克里斯托费尔(Christoffel Waelkens)和他的同事在1998年的研究,分析依巴谷卫星的资料,发现了大量(32)此类变星[3]

脉动

还不完全清楚天鹅座α型变星的脉动,它们并不限于窄幅的温度和光度脉动星的方式。可以是最明亮的A和B超巨星,也可能是O和F的恒星,显示某种不可预知的小规模(尺度)脉动类型。非绝热过程的奇怪模式迳向脉动只显现在最明亮的超巨星。通过假设它们是低质量的后红超巨星,低明亮的超巨星也有脉动模式,但多数的天鹅座α型变星似乎未显现经历过红巨星的阶段[4][5]

卖有可能诱发κ机制,造成铁不透明度的变化,产生观测上奇怪的短周期迳向和非迳向脉动方式。非绝热的G-模式可能会产生较长的周期变化,但这些均未在天鹅座α型变星上观测到[6]

列表

银河系的

名称 星座 发现 最大视星等 (mV)[7] 最小视星等 (mV)[7] 周期(天) 光谱类型 发光度 注解
CE Cam (HD 21389) 鹿豹座 Percy & Welsh (1983)[8] 4m.54 A0Iab 63,000[9]  
CS Cam 鹿豹座 4m.259 B9Ia  
大犬座η(Aludra) 大犬座 Kazarovets et al. (1999)[10] 2m.38 2m.48 4.70433 B5Ia 105,000[9]  
大犬座ο2 大犬座 Waelkens et al. (1998)[3] 2m.98 3m.04 24.44 B3Ia 219,000[11]  
仙后座κ 仙后座 Percy & Welsh (1983)[8] 4m.12 4m.21 2.64690 B1Ia 331,000[11]  
半人马座ο2 半人马座 5m.12 5m.22 46.3 A2Ia 136,000[12]  
仙王座ν 仙王座 Percy & Welsh (1983)[8] 4m.25 4m.35 A2 Iab 254,000[9]  
南十字座DL 南十字座 Waelkens et al. (1998)[3] 6m.24 6m.28 2.8778 B1.5Ia 242,000[13]  
天津四[5] 天鹅座 Lee (1910)[14] 1m.21 1m.29 A2 Ia 196,000[15] 原型
天鹅座σ 天鹅座 Abt (1957)[16] 4m.19 4m.26 120.2 B9 Iab 39,000[17]  
双子座3 双子座 Waelkens et al. (1998)[3] 5m.75 13.70 B3 Ia 200,000[18]  
狮子座ρ 狮子座 Olsen (1974)[19] 3m.83 3m.9 3.4271 B1Iab 295,000[11]  
参宿七[5] 猎户座 Waelkens et al. (1998)[3] 0m.17 0m.22 2.0748 B8Ia 279,000[20]

218,000[21]

Brightest member
ε Ori(Alnilam) 猎户座 Cousins (1960)[22] 1m.64 1m.74 2.0748 B0.5Iabea 275,000[11]

537,000[23]

 
猎户座χ2(Rigel) 猎户座 Waelkens et al. (1998)[3] 4m.68 4m.72 2.8682 B2Ia 446,000[11]  

其他星系

名称 星系 发现 最大视星等 (mV) 最小视星等 (mV) 周期(天) 光谱类型 发光度 注解
LHA 115-S 18[24] SMC 13m.3 复杂的 B[e]sg   可能是LBV
HDE 268835[24] LMC 10m.60 10m.68 >100 B8p    
HD 37974[24] LMC 10m.92 11m.00 400 B0.5Ia+    

参考资料

  1. ^ Nonradial Pulsation. Universität Wien. [2010-02-22]. (原始内容存档于2009-10-24). 
  2. ^ Kholopov, P. N.; Samus', N. N.; Frolov, M. S.; Goranskij, V. P.; Gorynya, N. A.; Kireeva, N. N.; Kukarkina, N. P.; Kurochkin, N. E.; Medvedeva, G. I.; Perova, N. B. VizieR Online Data Catalog: General Catalog of Variable Stars, 4th Ed. (GCVS4) (Kholopov+ 1988). VizieR On-line Data Catalog: II/139B. Originally published in: Moscow: Nauka Publishing House (1985-1988). 1996, 2139: 0. Bibcode:1996yCat.2139....0K. 
  3. ^ 3.0 3.1 3.2 3.3 3.4 3.5 Waelkens, C.; Aerts, C.; Kestens, E.; Grenon, M.; Eyer, L. Study of an unbiased sample of B stars observed with Hipparcos: the discovery of a large amount of new slowly pulsating B star. Astronomy and Astrophysics. 1998, 330: 215–21. Bibcode:1998A&A...330..215W. 
  4. ^ Saio, H.; Georgy, C.; Meynet, G. Strange-Mode Instability for Micro-Variations in Luminous Blue Variables. Progress in Physics of the Sun and Stars: A New Era in Helio- and Asteroseismology. Proceedings of a Fujihara Seminar held 25–29 November. Astronomical Society of the Pacific Conference Series 479. 2013: 47. Bibcode:2013ASPC..479...47S. arXiv:1305.4728 . 
  5. ^ 5.0 5.1 5.2 Saio, H.; Georgy, C.; Meynet, G. Evolution of blue supergiants and Cygni variables: puzzling CNO surface abundances. Monthly Notices of the Royal Astronomical Society. 2013, 433 (2): 1246–1257. Bibcode:2013MNRAS.433.1246S. arXiv:1305.2474 . doi:10.1093/mnras/stt796. 
  6. ^ Saio, Hideyuki. Linear analyses for the stability of radial and non-radial oscillations of massive stars. Monthly Notices of the Royal Astronomical Society. 2011, 412 (3): 1814–1822. Bibcode:2011MNRAS.412.1814S. ISSN 0035-8711. arXiv:1011.4729 . doi:10.1111/j.1365-2966.2010.18019.x. 
  7. ^ 7.0 7.1 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. 
  8. ^ 8.0 8.1 8.2 Percy, J. R.; Welch, D. L. Photometric variability of B- and A-type supergiants. Publications of the Astronomical Society of the Pacific. 1983, 95: 491. Bibcode:1983PASP...95..491P. ISSN 0004-6280. doi:10.1086/131198. 
  9. ^ 9.0 9.1 9.2 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 , doi:10.1002/asna.200911355 
  10. ^ 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. 
  11. ^ 11.0 11.1 11.2 11.3 11.4 Crowther, P. A.; Lennon, D. J.; Walborn, N. R. Physical parameters and wind properties of galactic early B supergiants. Astronomy and Astrophysics. 2006, 446: 279. Bibcode:2006A&A...446..279C. arXiv:astro-ph/0509436 . doi:10.1051/0004-6361:20053685. 
  12. ^ Kaufer, A.; Stahl, O.; Wolf, B.; Gaeng, T.; Gummersbach, C. A.; Kovacs, J.; Mandel, H.; Szeifert, T. Long-term spectroscopic monitoring of BA-type supergiants. I. Halpha_ line-profile variability.. Astronomy and Astrophysics. 1996, 305: 887–901. Bibcode:1996A&A...305..887K. 
  13. ^ Lamers, Henny J. G. L. M.; Snow, Theodore P.; Lindholm, Douglas M. Terminal Velocities and the Bistability of Stellar Winds. The Astrophysical Journal. 1995, 455: 269. Bibcode:1995ApJ...455..269L. ISSN 0004-637X. doi:10.1086/176575. 
  14. ^ Lee, O. J. Four stars having variable radial velocities.. The Astrophysical Journal. 1910, 31: 176. Bibcode:1910ApJ....31..176L. ISSN 0004-637X. doi:10.1086/141741. 
  15. ^ Schiller, F.; Przybilla, N. Quantitative spectroscopy of Deneb. Astronomy & Astrophysics. 2008, 479 (3): 849–858. Bibcode:2008A&A...479..849S. arXiv:0712.0040 . doi:10.1051/0004-6361:20078590. 
  16. ^ Abt, Helmut A. The Variability of Supergiants.. The Astrophysical Journal. 1957, 126: 138. Bibcode:1957ApJ...126..138A. ISSN 0004-637X. doi:10.1086/146379. 
  17. ^ Markova, N.; Puls, J. Bright OB stars in the Galaxy. Astronomy and Astrophysics. 2008, 478 (3): 823–842. Bibcode:2008A&A...478..823M. ISSN 0004-6361. arXiv:0711.1110 . doi:10.1051/0004-6361:20077919. 
  18. ^ Kudritzki, R. P.; Puls, J.; Lennon, D. J.; Venn, K. A.; Reetz, J.; Najarro, F.; McCarthy, J. K.; Herrero, A. The wind momentum-luminosity relationship of galactic A- and B-supergiants. Astronomy and Astrophysics. 1999, 350: 970. Bibcode:1999A&A...350..970K. arXiv:astro-ph/9910449 . 
  19. ^ Olsen, E. H. Variable Stars among the Four-Colour (uvby) Standard Stars. Information Bulletin on Variable Stars. 1974, 925: 1. Bibcode:1974IBVS..925....1O. 
  20. ^ Chesneau, O.; Kaufer, A.; Stahl, O.; Colvinter, C.; Spang, A.; Dessart, L.; Prinja, R.; Chini, R. The variable stellar wind of Rigel probed at high spatial and spectral resolution. Astronomy & Astrophysics. 2014, 566: 18. Bibcode:2014A&A...566A.125C. arXiv:1405.0907 . doi:10.1051/0004-6361/201322894. A125. 
  21. ^ Przybilla, N.; et al. Quantitative spectroscopy of BA-type supergiants. Astronomy and Astrophysics. January 2006, 445 (3): 1099–1126. Bibcode:2006A&A...445.1099P. arXiv:astro-ph/0509669 . doi:10.1051/0004-6361:20053832. 
  22. ^ Cousins, A. W. J. New Bright Variable Stars. Monthly Notes of the Astron. Soc. Southern Africa. 1960, 19: 56. Bibcode:1960MNSSA..19...56C. 
  23. ^ Searle, S. C.; Prinja, R. K.; Massa, D.; Ryans, R. Quantitative studies of the optical and UV spectra of Galactic early B supergiants. I. Fundamental parameters. Astronomy and Astrophysics. 2008, 481 (3): 777–97. Bibcode:2008A&A...481..777S. arXiv:0801.4289 . doi:10.1051/0004-6361:20077125. 
  24. ^ 24.0 24.1 24.2 van Genderen, A. M.; Sterken, C. Light variations of massive stars (α Cyg variables). Astronomy and Astrophysics. 2002, 386 (3): 926–935. Bibcode:2002A&A...386..926V. doi:10.1051/0004-6361:20020360. 

Samus N.N., Durlevich O.V., et al. Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.)