VY Canis Majoris
 Actual image of VY Canis Majoris (brightest star in the image) and its surrounding molecular cloud complex in the open cluster NGC 2362 as seen from the Rutherfurd Observatory of the Columbia University in New York, United States on the evening of 7 September 2014, Sunday. |
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| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Canis Major |
| Right ascension | 07h 22m 58.32877s |
| Declination | −25° 46′ 03.2355″ |
| Apparent magnitude (V) | 6.5 to 9.6 |
| Characteristics | |
| Spectral type | (M2.5I-)M3-M4.5 |
| Variable type | Semiregular |
| Astrometry | |
| Radial velocity (Rv) | 41 km/s |
| Proper motion (μ) |
RA: 9.84 mas/yr Dec.: 0.75 mas/yr |
| Parallax (π) | 0.83 ± 0.1mas |
| Distance | ~3,840 ly (1,170pc) |
| Details | |
| Mass | 17 ± 8 M☉ |
| Radius | 1,420 ± 120 R☉ |
| Luminosity | ~270,000 L☉ |
| Surface gravity (log g) | -0.6 cgs |
| Temperature | ~3,490 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation Canis Major. It is one of the largest stars (at one time it was the largest known) and also one of the most luminous of its type. It has a radius of approximately 1,420 solar radii (990,000,000 km; 6.6 au), and is located about 1.2 kiloparsecs (3,900 light-years) from Earth.
VY Canis Majoris is a single star categorized as a semiregular variable with an estimated period of 2,000 days. It has an average density of 5 to 10 mg/m3. If placed at the center of the Solar System, VY Canis Majoris's surface would extend beyond the orbit of Jupiter, although there is still considerable variation in estimates of the radius.
The first known recorded observation of VY Canis Majoris is in the star catalogue of Jérôme Lalande, on 7 March 1801, which lists it as a 7th magnitude star. Further 19th-century studies of its apparent magnitude demonstrate that the star has been fading since 1850. Since 1847, VY Canis Majoris has been described as a crimson star. During the 19th century, observers measured at least six discrete components, suggesting that it might be a multiple star. These discrete components are now known to be bright areas in the surrounding nebula. Visual observations in 1957 and high-resolution imaging in 1998 showed that there are no companion stars.
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