BI Cygni

The importance of BI Cygni in today's society is undeniable. Since time immemorial, BI Cygni has been the subject of attention and study by experts in different disciplines. Whether as a source of inspiration, as a subject of debate or as a protagonist of historical events, BI Cygni has left an indelible mark on culture and collective consciousness. In this article, we will explore the impact of BI Cygni in various areas and analyze its relevance today. From its influence on art and literature, to its role in politics and science, BI Cygni continues to be an object of fascination and controversy, sparking interest and reflection in contemporary society.

BI Cygni
BI Cygni is the small very red dot right on the left edge of this image. The bright star at the centre is γ Cygni and north is to the right.
Credit: Erik Larsen
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 20h 21m 21.8869s[1]
Declination 36° 55′ 55.729″[1]
Apparent magnitude (V) 8.4 – 9.9[2]
Characteristics
Evolutionary stage Red supergiant
Spectral type M4 Iab[2]
Variable type Lc[2]
Astrometry
Radial velocity (Rv)−7.48±0.42[1] km/s
Proper motion (μ) RA: −2.751[1] mas/yr
Dec.: −5.459[1] mas/yr
Parallax (π)0.3541±0.0377 mas[1]
Distance4,349+548
−440 ly
(1,334+168
−135 pc)[3]
Absolute magnitude (MV)−6.78[4]
Details
Mass17[5] M☉
Radius852+12
−9 – 908+12
−10[3] R☉
Luminosity89,300[5] L☉
Surface gravity (log g)-0.35[6] cgs
Temperature3,575[3][5] K
Metallicity +0.40[6] dex
Age>12[5] Myr
Other designations
RAFGL 2559, BI Cyg, BD+36 4025, WDS J20214+3656, TIC 13249363, TYC 2684-522-1, GSC 02684-00522, IRAS 20194+3646, 2MASS J20212192+3655555
Database references
SIMBADdata

BI Cygni (BI Cyg, IRC +40408, BD+36 4025) is a red supergiant in the constellation Cygnus. It is an irregular variable star with a maximum brightness of magnitude 8.4 and a minimum of magnitude 9.9. It is considered a member of the Cygnus OB1 stellar association,[4] its distance is around 1,300 parsecs (4,200 ly) of the Solar System. It is less than a degree south of another variable red supergiant, BC Cygni.

A visual band light curve for BI Cygni, plotted from INTEGRAL OMC data[7]

BI Cyg is a slow irregular variable star classified as type Lc, an irregular supergiant. Its brightness changes between extremes of magnitude 8.4 and 9.9.[2] Frequency analysis of its light curve shows no significant periods.[8]

BI Cyg is one of the largest known stars with a radius around 850 R☉, measured by its angular diameter by the CHARA array.[3] It is about 90,000 times more luminous that the Sun and has a cool effective temperature of 3,535 K.[5] Its mass is estimated at 17 solar masses, and it took 12 million years to enter the red supergiant phase.[5]

See also

Notes

References

  1. ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  3. ^ a b c d Norris, Ryan P. (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PDF) (PhD). Georgia State University.
  4. ^ a b Table 4 in Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (August 2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
  5. ^ a b c d e f Comerón, F.; Djupvik, A. A.; Schneider, N.; Pasquali, A. (October 2020). "The historical record of massive star formation in Cygnus". Astronomy & Astrophysics. 2009: A62. arXiv:2009.12779. Bibcode:2020A&A...644A..62C. doi:10.1051/0004-6361/202039188. S2CID 221970180.
  6. ^ a b Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevič, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; De Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. S2CID 131780028.
  7. ^ "OMC Archive". OMC Archive. The Astronomical Data Centre at CAB. Retrieved 19 December 2021.
  8. ^ Kiss, L. L; Szabó, Gy. M; Bedding, T. R (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise". Monthly Notices of the Royal Astronomical Society. 372 (4): 1721–1734. arXiv:astro-ph/0608438. Bibcode:2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x. S2CID 5203133.