Eta Canis Majoris
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Canis Major |
| Right ascension | 07h 24m 11.1s |
| Declination | -29° 18′ 11″ |
| Apparent magnitude (V) | 2.45 |
| Characteristics | |
| Spectral type | B5 Ia |
| U-B color index | -0.72 |
| B-V color index | -0.09 |
| Variable type | α Cyg |
| Astrometry | |
| Radial velocity (Rv) | 41 km/s |
| Proper motion (μ) | RA: -3.76 mas/yr Dec.: 6.66 mas/yr |
| Parallax (π) | 1.02 ± 0.57 mas |
| Distance | approx. 3000 ly (approx. 1000 pc) |
| Absolute magnitude (MV) | -7.51 |
| Details | |
| Mass | 15 M☉ |
| Radius | 32.6 R☉ |
| Luminosity | 100,000 L☉ |
| Temperature | 18,000 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Eta Canis Majoris (η CMa / η Canis Majoris) is a star in the constellation Canis Major. It also has the traditional name Aludra.
Aludra shines brightly in the skies in spite of a large distance from Earth due to being intrinsically many times brighter (absolute magnitude) than the Sun. A blue supergiant, Aludra has only been around a fraction of the time our Sun has, yet is already in the last stages of its life. It is still expanding and may be becoming a red supergiant, or perhaps has already passed that phase, but in either case it will become a supernova within the next few million years.
The name Aludra originates from the Arabic: عذرا al-‘aðrā "the virgin". In ancient times Arabic astrologers/astronomers referred to a group of four stars in the Canis Major constellation, also known as the "Greater Dog", as Al 'Adhara "the virgins".
η Canis Majoris classified as an Alpha Cygni type variable star and its brightness varies from magnitude +2.38 to +2.48
