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Epsilon Carinae

Epsilon Carinae
Diagram showing star positions and boundaries of the Carina constellation and its surroundings
Cercle rouge 100%.svg

Location of ε Carinae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension 08h 22m 30.83526s
Declination −59° 30′ 34.1431″
Apparent magnitude (V) 1.86 (2.166/4.121)
Characteristics
Spectral type K3 III + B2 Vp
U−B color index +0.19
B−V color index +1.27
Variable type Eclipsing (suspected)
Astrometry
Radial velocity (Rv) +11.6 km/s
Proper motion (μ) RA: –25.52 mas/yr
Dec.: 22.72 mas/yr
Parallax (π) 5.39 ± 0.42mas
Distance 610 ± 50 ly
(190 ± 10 pc)
Details
ε Car A
Mass 9.0 ± 0.9 M
Temperature 3,523 K
Age 31.2 ± 10.1 Myr
ε Car B
Mass 7.30 M
Temperature 20,417 K
Other designations
Avior, CD−59°1032, FK5 315, HD 71129, HIP 41037, HR 3307, SAO 235932.
Database references
SIMBAD data

Epsilon Carinae (ε Carinae, abbreviated Epsilon Car, ε Car), also named Avior, is a binary star in the southern constellation of Carina. At apparent magnitude +1.86 it is one of the brightest stars in the night sky, but is not visible from the northern hemisphere. The False Cross is an asterism formed of Delta Velorum, Kappa Velorum, Iota Carinae and ε Carinae. It is so called because it is sometimes mistaken for the Southern Cross, causing errors in astronavigation.

Epsilon Carinae is located roughly 560–660 light-years (170–200 parsecs) from the Sun. Measurements during the Hipparcos mission give the pair an angular separation of 0.46 arcseconds with a difference in magnitude of 2.0. At their estimated distance, this angle is equivalent to a physical separation of around 4 astronomical units. This pair may form an eclipsing binary system with a period of 785 days (2.15 years), resulting in a magnitude change of 0.12 during each eclipse.

The primary component has an apparent visual magnitude of 2.2, which by itself would still make it the third-brightest star in the constellation. It is an evolved giant star with a stellar classification of K0 III. However, examination of the ultraviolet flux from this star suggests it may instead be of spectral type K7. The fainter secondary companion has an apparent visual magnitude of 4.1, which, if it were a solitary star, would be bright enough to be seen with the naked eye. This is a hot, core hydrogen-fusing B-type main sequence star of spectral class B2 Vp. The secondary may itself have an orbiting stellar companion of spectral class F8.


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