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| Astrometry | |
|---|---|
| Absolute magnitude (MV) | -9 |
| Characteristics | |
| Spectral type | M2 Iab |
| Details | |
| Mass | 25-40 or 100 M☉ |
| Radius | 1600-1900 R☉ |
| Luminosity | 275,000-575,000(bolometric) L☉ |
| Temperature | 3300-3650 K |
| Observation data Epoch J2000 Equinox J2000 |
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| Constellation | Cepheus |
| Right ascension | 21h 56m 39.14s |
| Declination | +63° 37′ 32″ |
VV Cephei is an eclipsing binary star system located in the constellation Cepheus, approximately 3,000 light years from Earth. A red supergiant fills the system's Roche lobe when closest to its companion blue star, the latter appearing to be on the main sequence. Matter flows from the red supergiant onto the blue companion.
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VV Cephei A
VV Cephei A, the supergiant, is one of the largest stars known, and believed the third largest star in this galaxy (after the hypergiant WOH G64). It is of spectral type M2 and is approximately 1,600–1,900 times the Sun's diameter. If placed in our solar system, the binary system would extend past the orbit of Jupiter and approach that of Saturn. VV Cephei is 275,000-575,000 times more luminous than the Sun. As is true for many red supergiants, a stellar wind flows off the system at a velocity of approximately 25 kilometers per second.1 VV Cephei A's mass estimated from its orbital motion is about 100 solar masses, but its luminosity suggests a mass 25-40 solar masses. Consequently, the actual mass is unknown.
VV Cephei B
VV Cephei B, the blue main sequence star, is separated from the larger star by a distance of 25 AU on average, with the distance varying between 17 and 34 AU. It is a B0 star about 10 times the Sun's diameter and about 100,000 times its luminosity. The orbital period of the system is 7,430 days (20.3 years). The eclipse lasts about 1,300 days, and is total for about a year and a half. The midpoint of the last eclipse was in early January 1998.2
See also
References
- ^ W. H. Bauer, P. D. Bennett, & A. Brown 2007 Astrophysical Journal Supplement Series 171, 249-259.
- ^ W. H. Bauer, P. D. Bennett, & A. Brown 2007. See especially their Figure 1, p. 250.
External links
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