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 [1]   mas/yr
Dec.: −6.307 [1]   mas/yr
Parallax (π)0.5760 ± 0.0500  mas [1]
Distance 1,710+40
−40 [5]   pc
Absolute magnitude  (MV)−7.71 [6]
Details [4]
Mass 19  M☉
Radius 1,031 [7]   R☉
Luminosity 204,000 [5]   L☉
Temperature 3,605 [8]   K
Minimum (1900)
Radius 1,553  R☉
Luminosity 145,000  L☉
Temperature 2,858  K
Maximum (2000)
Radius 856  R☉
Luminosity112,000  L☉
Temperature 3,614  K
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.

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 calculated to have an effective temperature of 2,858 to 3,614 K and to vary between 112,000 to 145,000 L☉. The size at its brightest and coolest has been calculated to be 1,553 R☉ compared to 856 R☉ at the hottest and faintest. It is one of largest stars known. If it were in the place of the Sun, its photosphere would engulf the orbit of Jupiter assuming the maximum radius of 1,553 R☉. 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. [11]

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

Related Research Articles

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KY Cygni is a red supergiant of spectral class M3.5Ia located in the constellation Cygnus. It is approximately 5,000 light-years away.

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<span class="mw-page-title-main">Cygnus OB2-12</span> Blue hypergiant star

Cygnus OB2 #12 is an extremely luminous blue hypergiant with an absolute bolometric magnitude of −10.9, among the most luminous stars known in the galaxy. This makes the star nearly two million times more luminous than the Sun, although estimates were even higher when the star was first discovered. It is now known to be a binary, with the companion approximately a tenth as bright. A very approximate initial estimate of the orbit gives the total system mass as 120 M☉ and the period as 30 years.

<span class="mw-page-title-main">Cygnus OB2-8A</span> Spectroscopic binary star near the center of Cygnus OB2

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<span class="mw-page-title-main">NO Aurigae</span> Star in the constellation Auriga

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<span class="mw-page-title-main">V602 Carinae</span> Star in the constellation Carina

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<span class="mw-page-title-main">TZ Cassiopeiae</span> Star in the constellation Cassiopeia

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63 Cygni is a single star in the northern constellation of Cygnus, located around 1,030 light years away from Sun. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.56. 63 Cyg is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.

<span class="mw-page-title-main">PZ Cassiopeiae</span> Star in the constellation Cassiopeia

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<span class="mw-page-title-main">31 Cygni</span> Triple star system in the constellation Cygnus

31 Cygni, also known as ο1 Cygni, Omicron1 Cygni, or V695 Cygni, is a triple star system about 750 light years away in the constellation Cygnus.

<span class="mw-page-title-main">TT Cygni</span> Star in the constellation Cygnus

TT Cygni is a carbon star located 561 parsecs (1,830 ly) away in the northern constellation of Cygnus. It is classified as a semiregular variable of subtype SRb that ranges in brightness from magnitude 7.26 down to 8.0 with a period of 118 days. This object is called a carbon star because it has a high ratio of carbon to oxygen in its surface layers. The carbon was produced by helium fusion, dredged up from inside the star by deep convection triggered by a flash from the helium shell.

<span class="mw-page-title-main">RW Cygni</span> Star in the constellation Cygnus

RW Cygni is a semiregular variable star in the constellation Cygnus, about a degree east of 2nd magnitude γ Cygni. Its apparent magnitude varies between 8.05 and 9.70 and its spectral type between M3 and M4.

<span class="mw-page-title-main">BI Cygni</span> Star in the constellation Cygnus

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 stellar Cygnus OB1 association, its distance is around 2,600 parsecs (8,500 ly) of the Solar System. It is less than a degree south of another variable red supergiant, BC Cygni.

<span class="mw-page-title-main">V1331 Cygni</span> Star in constellation Cygnus

V1331 Cygni is a young star in the constellation Cygnus. V1331 Cyg is located in the dark nebula LDN 981.

<span class="mw-page-title-main">V1027 Cygni</span> Star in the constellation Cygnus

V1027 Cygni is a luminous yellow supergiant star located in the constellation of Cygnus, about 14,000 light years away. For a time, it was thought that it could be a low-mass post-AGB star, however recent parallax measurements published in Gaia DR3 have shown this to likely not be the case, and instead it is likely a massive yellow supergiant star.

<span class="mw-page-title-main">X Cygni</span> Variable star in the constellation Cygnus

X Cygni is a variable star in the northern constellation of Cygnus, abbreviated X Cyg. This is a Delta Cephei variable that ranges in brightness from an apparent visual magnitude of 5.85 down to 6.91 with a period of 16.386332 days. At it brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 628 light years based on parallax measurements. It is drifting further away with a radial velocity of 8.1 km/s. This star is a likely member of the open cluster Ruprecht 173.

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. 1 2 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.
  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. ↑ 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. ↑ Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv: 1905.03744 . Bibcode:2019AJ....158...20M. doi: 10.3847/1538-3881/ab1cbd . S2CID   148571616.
  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. ↑ 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.
  12. ↑ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
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