Iota Canis Majoris
  | |
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 56m 08.22413s |
| Declination | −17° 03′ 15.2675″ |
| Apparent magnitude (V) | 4.40 (4.36 - 4.40) |
| Characteristics | |
| Spectral type | B3 Ib or B3 Ib/II |
| U−B color index | −0.74 |
| B−V color index | −0.07 |
| Variable type | Beta Cephei? |
| Astrometry | |
| Radial velocity (Rv) | +41.20 km/s |
| Proper motion (μ) | RA: −3.56 ± 0.17 mas/yr Dec.: +2.42 ±0.20 mas/yr |
| Parallax (π) | 1.04 ± 0.20 mas |
| Distance | approx. 3,100 ly (approx. 1,000 pc) |
| Absolute magnitude (MV) | −5.51 |
| Details | |
| Mass | 12.5 M☉ |
| Radius | 25.9 R☉ |
| Luminosity | 47,000 L☉ |
| Surface gravity (log g) | 2.60 cgs |
| Temperature | 17,000 K |
| Metallicity [Fe/H] | −0.17 dex |
| Rotational velocity (v sin i) | 27±4 km/s |
| Age | 14.8 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Canis Majoris, Latinized from ι Canis Majoris, is a solitary variable supergiant star in the southern constellation of Canis Major. It is visible to the naked eye with an apparent visual magnitude that varies between +4.36 and +4.40. The distance to this star is approximately 3,100 light years based on parallax measurements. It is drifting further away with a radial velocity of +41.2 km/s.
Iota Canis Majoris is a massive blue-white B-type supergiant with a stellar classification of B3 Ib. It has been classified as a Beta Cephei type variable star, but the supergiant spectral type and a period of over a month mean it is no longer considered to be of that type. This star is 14.8 million years old and is spinning with a projected rotational velocity of 27 km/s. It has 12.5 times the mass and 25.9 times the radius of the Sun. Iota Canis Majoris is radiating 47,000 times the luminosity of the Sun from its photosphere at an effective temperature of 17,000 K.
The star displays a bow shock feature from its interaction with the interstellar medium, but this nebulosity is not aligned with the star's motion through the galaxy.