V354 Cephei
V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located approximately 9,000 light-years away from our Sun, and is currently considered one of the largest known stars, with a radius estimate of 1,520 times that of the Sun, or 1,060,000,000 km at its greatest extent. If it were placed in the center of the Solar System, it would extend to 7 AU, between the orbits of Jupiter and Saturn.
The luminosity, and hence the size, of V354 Cep are disputed. Levesque et al 2005, find a high luminosity and consequently very large size of 1,520 R☉, making it one of the List of largest stars. From the same data, Mauron et al 2011 derive a much smaller luminosity of 76,000 L☉, which implies a much smaller size around 690 R☉. They note the discrepancy but are unable to explain it.[7]
There are similar differences in the visual extinctions derived, between two and six magnitudes.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 33m 34.643s[1] |
| Declination | +58° 53′ 47.05″[1] |
| Apparent magnitude (V) | 10.82 to 11.35[2] |
| Characteristics | |
| Spectral type | M2.5 Iab[3] |
| B−V color index | +3.18[4] |
| Variable type | LC[2] |
| Astrometry | |
| Distance | ~9,000[5] ly (3,500 pc) |
| Absolute magnitude (MV) | -7.57 (variable)[4] |
| Details | |
| Radius | 1,520[6] R☉ |
| Luminosity | 76,000[7] - 369,000[6] L☉ |
| Surface gravity (log g) | −0.5[6] cgs |
| Temperature | 3,650[6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
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