天鵝座α型變星
天鵝座α型變星是顯示出非徑向脈動的變星,意味著當恆星表面有些地方收縮時,而同時也有些地方是擴張的[1]。它們是光譜類型B或A的超巨星,亮度變化在0.1視星等,並與脈動相關聯,而由於和多脈動週期的節拍相關聯,因而通常是不規則變星。脈衝週期通常有幾天到幾個星期的周期。
這種變星的原型是天津四(天鵝座α),顯示的亮度在1.21 和 +1.29 之間波動。眾所周知很多在早期的超巨星都有小幅快速的變動,但之前它們未被歸為一類,直到1985年的變星總表第四版才收錄為變星的一種,縮寫的字母為ACYG(Alpha Cygni variable stars)[2]。許多高光度藍變星(LBVs)在它們平靜(熱)階段顯示出天鵝座α型變星的型態,但在這種情況下一般仍使用LBV的分類。
克裡斯托費爾(Christoffel Waelkens)和他的同事在1998年的研究,分析依巴谷衛星的資料,發現了大量(32)此類變星[3]。
脈動
[编辑]還不完全清楚天鵝座α型變星的脈動,它們並不限於窄幅的溫度和光度脈動星的方式。可以是最明亮的A和B超巨星,也可能是O和F的恆星,顯示某種不可預知的小規模(尺度)脈動類型。非絕熱過程的奇怪模式逕向脈動只顯現在最明亮的超巨星。通過假設它們是低質量的後紅超巨星,低明亮的超巨星也有脈動模式,但多數的天鵝座α型變星似乎未顯現經歷過紅巨星的階段[4][5]。
賣有可能誘發κ機制,造成鐵不透明度的變化,產生觀測上奇怪的短週期逕向和非逕向脈動方式。非絕熱的G-模式可能會產生較長的週期變化,但這些均未在天鵝座α型變星上觀測到[6]。
列表
[编辑]銀河系的
[编辑]名稱 | 星座 | 發現 | 最大視星等 (mV)[7] | 最小視星等 (mV)[7] | 週期(天) | 光譜類型 | 發光度 | 註解 |
---|---|---|---|---|---|---|---|---|
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] | |
半人馬座ο2 | 半人馬座 | 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] | 天鵝座 | Lee (1910)[14] | 1m.21 | 1m.29 | A2 Ia | 196,000[15] | 原型 | |
天鵝座σ | 天鵝座 | Abt (1957)[16] | 4m.19 | 4m.26 | 120.2 | B9 Iab | 39,000[17] | |
雙子座3 | 雙子座 | Waelkens et al. (1998)[3] | 5m.75 | 13.70 | B3 Ia | 200,000[18] | ||
獅子座ρ | 獅子座 | Olsen (1974)[19] | 3m.83 | 3m.9 | 3.4271 | B1Iab | 295,000[11] | |
參宿七[5] | 獵戶座 | Waelkens et al. (1998)[3] | 0m.17 | 0m.22 | 2.0748 | B8Ia | 279,000[20] 218,000[21] |
Brightest member |
ε Ori(Alnilam) | 獵戶座 | Cousins (1960)[22] | 1m.64 | 1m.74 | 2.0748 | B0.5Iabea | 275,000[11] 537,000[23] |
|
獵戶座χ2(Rigel) | 獵戶座 | Waelkens et al. (1998)[3] | 4m.68 | 4m.72 | 2.8682 | B2Ia | 446,000[11] |
其他星系
[编辑]名稱 | 星系 | 發現 | 最大視星等 (mV) | 最小視星等 (mV) | 週期(天) | 光譜類型 | 發光度 | 註解 |
---|---|---|---|---|---|---|---|---|
LHA 115-S 18[24] | SMC | 13m.3 | 複雜的 | 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+ |
參考資料
[编辑]- ^ Nonradial Pulsation. Universität Wien. [2010-02-22]. (原始内容存档于2009-10-24).
- ^ 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.
- ^ 3.0 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.
- ^ 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 .
- ^ 5.0 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.
- ^ 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.
- ^ 7.0 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.
- ^ 8.0 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.
- ^ 9.0 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
- ^ 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.
- ^ 11.0 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Abt, Helmut A. The Variability of Supergiants.. The Astrophysical Journal. 1957, 126: 138. Bibcode:1957ApJ...126..138A. ISSN 0004-637X. doi:10.1086/146379.
- ^ 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.
- ^ 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 .
- ^ Olsen, E. H. Variable Stars among the Four-Colour (uvby) Standard Stars. Information Bulletin on Variable Stars. 1974, 925: 1. Bibcode:1974IBVS..925....1O.
- ^ 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.
- ^ 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.
- ^ Cousins, A. W. J. New Bright Variable Stars. Monthly Notes of the Astron. Soc. Southern Africa. 1960, 19: 56. Bibcode:1960MNSSA..19...56C.
- ^ 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.
- ^ 24.0 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.)