Jump to content

Alpha Cygni variable

From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by Lithopsian (talk | contribs) at 20:27, 14 August 2015 (→List). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Alpha Cygni variables are variable stars which exhibit non-radial pulsations, meaning that some portions of the stellar surface are contracting at the same time others parts expand.[1] They are supergiant stars of spectral types B or A. Variations in brightness on the order of 0.1 magnitudes are associated with the pulsations, which often seem irregular, due to beating of multiple pulsation periods. The pulsations typically have periods of several days to several weeks.

The prototype of these stars, Deneb (α Cygni), exhibits fluctuations in brightness between magnitudes +1.21 and +1.29.

A large number (32) were discovered by Christoffel Waelkens and colleagues analysing Hipparcos data in a 1998 study.[2]

List

Galactic

Designation (name) Constellation Discovery Maximum Apparent magnitude (mV)[3] Minimum Apparent magnitude (mV)[3] Period (days) Spectral class Luminosity Comment
CE Cam (HD 21389) Camelopardalis Percy & Welsh (1983)[4] 4m.54 A0Iab    
η CMa (Aludra) Canis Major 2m.38 2m.48 4.70433 B5Ia    
ο2 CMa Canis Major Waelkens et al (1998)[2] 2m.98 3m.04 24.44 B3Ia 219,000[5]  
κ Cas Cassiopeia Percy & Welsh (1983)[4] 4m.12 4m.21 2.64690 B1Ia 331,000[5]  
ν Cep Cepheus Percy & Welsh (1983)[4] 4m.25 4m.35 A2 Iab    
DL Cru Crux Waelkens et al (1998)[2] 6m.24 6m.28 2.8778 B1.5Ia    
Deneb[6] Cygnus Lee (1910)[7] 1m.21 1m.29 A2 Ia   Prototype
σ Cyg Cygnus 4m.19 4m.26 120.2 B9 Iab    
3 Gem Gemini Waelkens et al (1998)[2] 5m.75 13.70 B3 Ia    
ρ Leo Leo Olsen (1974)[8] 3m.83 3m.9 3.4271 B1Iab 295,000[5]  
β Ori (Rigel)[6] Orion Waelkens et al (1998)[2] 0m.17 0m.22 2.0748 B8Ia 279,000[9]

218,000[10]

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

537,000[12]

 
χ2 Ori (Rigel) Orion Waelkens et al (1998)[2] 4m.68 4m.72 2.8682 B2Ia 446,000[5]  

Extragalactic

Designation (name) Galaxy Discovery Maximum Apparent magnitude (mV) Minimum Apparent magnitude (mV) Period (days) Spectral class Luminosity Comment
LHA 115-S 18[13] SMC 13m.3 Complex B[e]sg   Possible LBV
HDE 268835[13] LMC 10m.60 10m.68 >100 B8p    
HD 37974[13] LMC 10m.92 11m.00 400 B0.5Ia+    

References

  1. ^ "Nonradial Pulsation". Universität Wien. Retrieved 2010-02-22.
  2. ^ a b c d e f Waelkens, C.; Aerts, C.; Kestens, E.; Grenon, M.; Eyer, L. (1998). "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. 330: 215–21. Bibcode:1998A&A...330..215W.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ^ a b . Bibcode:2009yCat....102025S. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)
  4. ^ a b c Percy, J. R.; Welch, D. L. (1983). "Photometric variability of B- and A-type supergiants". Publications of the Astronomical Society of the Pacific. 95: 491. doi:10.1086/131198. ISSN 0004-6280.
  5. ^ a b c d e Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1051/0004-6361:20053685, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1051/0004-6361:20053685 instead.
  6. ^ a b Saio, H.; Georgy, C.; Meynet, G. (2013). "Evolution of blue supergiants and Cygni variables: puzzling CNO surface abundances". Monthly Notices of the Royal Astronomical Society. 433 (2): 1246–1257. Bibcode:2013MNRAS.433.1246S. doi:10.1093/mnras/stt796.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  7. ^ Lee, O. J. (1910). "Four stars having variable radial velocities". The Astrophysical Journal. 31: 176. doi:10.1086/141741. ISSN 0004-637X.
  8. ^ . Bibcode:1974IBVS..925....1O. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)
  9. ^ Chesneau, O.; Kaufer, A.; Stahl, O.; Colvinter, C.; Spang, A.; Dessart, L.; Prinja, R.; Chini, R. (2014). "The variable stellar wind of Rigel probed at high spatial and spectral resolution". Astronomy & Astrophysics. 566: 18. Bibcode:2014A&A...566A.125C. doi:10.1051/0004-6361/201322894. A125.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ Przybilla, N.; et al. (January 2006). "Quantitative spectroscopy of BA-type supergiants". Astronomy and Astrophysics. 445 (3): 1099–1126. arXiv:astro-ph/0509669. Bibcode:2006A&A...445.1099P. doi:10.1051/0004-6361:20053832.
  11. ^ . Bibcode:1960MNSSA..19...56C. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)
  12. ^ Searle, S. C.; Prinja, R. K.; Massa, D.; Ryans, R. (2008). "Quantitative studies of the optical and UV spectra of Galactic early B supergiants. I. Fundamental parameters". Astronomy and Astrophysics. 481 (3): 777–97. arXiv:0801.4289. Bibcode:2008A&A...481..777S. doi:10.1051/0004-6361:20077125.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ a b c van Genderen, A. M.; Sterken, C. (2002). "Light variations of massive stars (α Cyg variables)". Astronomy and Astrophysics. 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.)

Stub icon

This variable star–related article is a stub. You can help Wikipedia by expanding it.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Alpha_Cygni_variable&oldid=676119101"