Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Carina |
Right ascension | 10h 13m 44.21739s [1] |
Declination | –70° 02′ 16.4563″ [1] |
Apparent magnitude (V) | 3.29 [2] |
Characteristics | |
Spectral type | B8 IIIe [3] |
U−B color index | –0.285 [4] |
B−V color index | –0.083 [4] |
Astrometry | |
Radial velocity (Rv) | +7.0 [2] km/s |
Proper motion (μ) |
RA: -36.01
[1]
mas/
yr Dec.: +7.09 [1] mas/ yr |
Parallax (π) | 9.54 ± 0.09 mas [1] |
Distance | 342 ± 3
ly (104.8 ± 1.0 pc) |
Absolute magnitude (MV) | −1.81 [5] |
Details | |
Radius | 7.20±0.14 [6] R☉ |
Luminosity | 918 [7] L☉ |
Surface gravity (log g) | 3.51 [7] cgs |
Temperature | 11,630 [7] K |
Rotational velocity (v sin i) | 240 [7] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Omega Carinae, Latinized from ω Carinae, is a star in the constellation Carina. With a declination greater than 70 degrees south of the celestial equator, it is the most southerly of the bright stars of Carina (third-magnitude or brighter), and it is part of a southern asterism known as the Diamond Cross. This star has an apparent visual magnitude of 3.3 and is located at a distance of about 342 light-years (105 parsecs) from Earth.
Omega Carinae has a stellar classification of B8 IIIe, [3] which places it in the category of Be stars, that display emission lines of hydrogen their spectrum. Omega Carinae is a shell star, [3] having a circumstellar disk of gas surrounding its equator. The luminosity class of III indicates it has evolved into a giant star, having exhausted the hydrogen at its core and left the main sequence. The effective temperature of 11,630 K [7] in its outer envelope is what gives this star the blue-white hue that is characteristic of B-type stars.
This star is rotating rapidly with a projected rotational velocity of 240 km/s, [7] which gives a lower limit to the star's azimuthal velocity along the equator. The critical equatorial velocity, at which the star would begin to break up, is 320 km s−1. The star's axis of rotation is inclined by an estimated angle of 70.8° to the line of sight from the Earth. [9]
In the next 7500 years, the south Celestial pole will pass close to this star (AD 5800) and then I Carinae. [10]
In Chinese, 南船 (Nán Chuán), meaning Southern Boat, refers to an asterism consisting of ω Carinae, V337 Carinae, PP Carinae, θ Carinae and β Carinae . [11] Consequently, ω Carinae itself is known as 南船四 (Nán Chuán sì, English: the Fourth Star of Southern Boat.) [12]