BC Cygni
BC Cygni
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  Credit: Erik Larsen | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
Constellation | Cygnus |
Right ascension | 20h 21m 38.55s |
Declination | 37° 31′ 58.9″ |
Apparent magnitude (V) | 9.0 - 10.8[1] |
| Characteristics | |
Spectral type | M3.5 Ia[2](M2 - M5[3]) |
| B−V color index | +3.13 - +3.21[3] |
Variable type | SRc[2] |
| Astrometry | |
| Distance | 1,230[3] pc |
| Absolute magnitude (MV) | −7.71[4] |
| Details[3] | |
| Mass | 19 M☉ |
| Minimum (1900) | |
| Radius | 1,553 R☉ |
| Luminosity | 145,000 L☉ |
| Temperature | 2,858 K |
| Maximum (2000) | |
| Radius | 856 R☉ |
| Luminosity | 112,000 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 87.2 which would place at a distance of 1,500 parsecs (4,890 light-years) of the Solar System; however, according to the measure of the parallax by the satellite Hipparcos (1.20 milliarcseconds). It is less than a degree north of another variable red supergiant, BI Cygni.
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 known stars. 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 6991320000000000000♠3.2×10−9 M☉ per year. This mass is an indication that this star will end up exploding as a supernova.
The brightness of BC Cyg varies from visual magnitude +9.0 and +10.8 with a period of 720 ± 40 days.[1] Between 1,900 and 2,000 appears to have increased its average brightness of 0.5 magnitudes.[3]
See also[edit]
- NML Cygni
- KY Cygni
- RW Cygni
References[edit]
^ ab 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. arXiv:astro-ph/0608438. Bibcode:2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ ab 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.
^ abcde 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.
^ 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. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901.
Categories:
- M-type supergiants
- Semiregular variable stars
- Cygnus (constellation)
- Hipparcos objects
- Durchmusterung objects
- Objects with variable star designations
- 2MASS objects
- IRAS catalogue objects
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