BC Cygni

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BC Cygni
Sadr Region rgb.jpg
Red circle.svg
BC Cygni is visible as a red star (circled). 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 38.55s [1]
Declination 37° 31′ 58.9″ [1]
Apparent magnitude  (V)9.0 - 10.8 [2]
Characteristics
Spectral type M3.5 Ia [3] (M2 - M5 [4] )
B−V color index +3.13 - +3.21 [4]
Variable type SRc [3]
Astrometry
Radial velocity (Rv)−20.97 [1]  km/s
Proper motion (μ)RA: −3.710  mas/yr [1]
Dec.: −6.307  mas/yr [1]
Parallax (π)0.5760 ± 0.0500  mas [1]
Distance 5,418+470
−430  ly
(1,662+144
−132  pc) [5]
Absolute magnitude  (MV)−7.71 [6]
Details
Mass 19 [4] [7]   M☉
Radius 1,031 [7] [lower-alpha 1]   R☉
Luminosity 150,000 [7]
204,000+159,000
−56,000 [8]   L☉
Temperature 3,535 [7]   K
Age >9 [7] [lower-alpha 2]   Myr
Other designations
BC  Cyg, HIP  100404, HV  3339, BD+37°3903, IRAS  20197+3722, 2MASS  J20213855+3731589
Database references
SIMBAD data

BC Cygni (BC Cyg, HIP 100404, BD + 37 3903) is a red supergiant and pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.

Contents

It is considered a member of the stellar Cygnus OB1 association, and within it the open cluster Berkeley 87, [9] which would place at a distance of 1,673 parsecs (5,000 ly) of the Solar System; [10] it is less than a degree north of another variable red supergiant, BI Cygni.[ citation needed ] According to its Gaia Data Release 3 parallax, it is at about 1,700 pc. [1]

BC Cygni was found to have a luminosity of 145,000  L☉ and an efective temperature of 2,858  K in the year 1900, and a luminosity of 112,000  L☉ and a temperature of 3,614 K in the year 2000. At its brightest and coolest has been calculated to be 1,553 R☉ compared to 856 R☉ at the hottest and faintest. [11] It is one of largest stars known, and currently is 1,031 times larger than the Sun. [7] [lower-alpha 1] If it were in the place of the Sun, its photosphere would engulf the entire inner solar system and reach close to the orbit of Jupiter. With a mass of about 19 M☉, it is estimated that the stellar mass loss, as dust, as the atomic and molecular gas could not be evaluators is 3.2×10−9  M☉ per year. [12]

A visual band light curve for BC Cygni, from AAVSO data BCCygLightCurve.png
A visual band light curve for BC Cygni, from AAVSO data

The brightness of BC Cyg varies from visual magnitude +9.0 and +10.8 with a period of 720 ± 40 days. [2] Between around the year 1900 and 2000 appears to have increased its average brightness of 0.5 magnitudes. [4]

See also

Notes

  1. 1 2 Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772  K:
    .
  2. ↑ This is only the age at which the star enters the red supergiant phase.

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References

  1. 1 2 3 4 5 6 7 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. 1 2 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.
  3. 1 2 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.
  4. 1 2 3 4 Turner, David G.; Rohanizadegan, Mina; Berdnikov, Leonid N.; Pastukhova, Elena N. (2006). "The Long-Term Behavior of the Semiregular M Supergiant Variable BC Cygni". The Publications of the Astronomical Society of the Pacific. 118 (849): 1533. Bibcode:2006PASP..118.1533T. doi: 10.1086/508905 .
  5. ↑ Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (2021-03-01). "Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv: 2012.05220 . Bibcode:2021AJ....161..147B. doi: 10.3847/1538-3881/abd806 . ISSN   0004-6256. Data about this star can be seen here.
  6. ↑ Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (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.
  7. 1 2 3 4 5 6 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.
  8. ↑ Davies, Ben; Beasor, Emma R. (March 2020). "The 'red supergiant problem': the upper luminosity boundary of Type II supernova progenitors". MNRAS . 493 (1): 468–476. arXiv: 2001.06020 . Bibcode:2020MNRAS.493..468D. doi: 10.1093/mnras/staa174 . S2CID   210714093.
  9. ↑ Sokal, Kimberly R.; Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel; Schmutz, Werner (2010). "Chandra Detects the Rare Oxygen-type Wolf-Rayet Star WR 142 and OB Stars in Berkeley 87". The Astrophysical Journal. 715 (2): 1327. arXiv: 1004.0462 . Bibcode:2010ApJ...715.1327S. doi:10.1088/0004-637X/715/2/1327. S2CID   119232391.
  10. ↑ de la Fuente, Diego; Román-Zúñiga, Carlos G.; Jiménez-Bailón, Elena; Alves, João; Garcia, Miriam; Venus, Sean (2021). "Clustered star formation toward Berkeley 87/ON2. I. Multiwavelength census and the population overlap problem". Astronomy and Astrophysics. 650: A156. arXiv: 2103.06062 . Bibcode:2021A&A...650A.156D. doi:10.1051/0004-6361/202040065. S2CID   232170603.
  11. ↑ Turner, David G.; Rohanizadegan, Mina; Berdnikov, Leonid N.; Pastukhova, Elena N. (2006-11-02). "The Long-Term Behavior of the Semiregular M Supergiant Variable BC Cygni". Publications of the Astronomical Society of the Pacific. 118 (849): 1533. Bibcode:2006PASP..118.1533T. doi:10.1086/508905. ISSN   1538-3873.
  12. ↑ Josselin, E.; Plez, B. (2007). "Atmospheric dynamics and the mass loss process in red supergiant stars". Astronomy and Astrophysics. 469 (2): 671. arXiv: 0705.0266 . Bibcode:2007A&A...469..671J. doi:10.1051/0004-6361:20066353. S2CID   17789027.
  13. ↑ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
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