Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Carina |
Right ascension | 09h 47m 06.12170s [1] |
Declination | –65° 04′ 19.2267″ [1] |
Apparent magnitude (V) | 2.97 [2] (+3.08/+6.25 [3]) |
Characteristics | |
Spectral type | A8 Ib + B7 III [4] |
U−B color index | +0.13 [2] |
B−V color index | +0.27 [2] |
Astrometry | |
Radial velocity (Rv) | +14 [4] km/s |
Proper motion (μ) |
RA: –11.51
[1]
mas/
yr Dec.: +4.71 [1] mas/ yr |
Parallax (π) | 2.27 ± 0.28 mas [1] |
Distance | approx. 1,400
ly (approx. 440 pc) |
Absolute magnitude (MV) | −5.26 [5] |
Details | |
υ Car A | |
Mass | 13 [4] M☉ |
Surface gravity (log g) | 1.1 ± 0.3 [4] cgs |
Temperature | 7,600 ± 350 [4] K |
Age | 12 [6] Myr |
υ Car B | |
Mass | 8 [4] M☉ |
Surface gravity (log g) | 3.3 ± 0.1 [4] cgs |
Temperature | 23,000 ± 1600 [4] K |
Other designations | |
A: HD 85124, HR 3891, SAO 250696 | |
B: HD 85123, HR 3890, SAO 250695 | |
Database references | |
SIMBAD | system |
A | |
B |
Upsilon Carinae, Latinized from υ Carinae, is a double star in the southern constellation of Carina. It is part of the Diamond Cross asterism in southern Carina. The Upsilon Carinae system has a combined apparent magnitude of +2.97 [2] and is approximately 1,400 light years (440 parsecs) from Earth. [1]
In Chinese, 海石 (Hǎi Dàn), meaning Sea Rock, refers to an asterism consisting of υ Carinae, ε Carinae, ι Carinae, HD 83183 and HD 84810. [8] Consequently, υ Carinae itself is known as 海石五 (Hǎi Dàn wǔ, English: the Fifth Star of Sea Rock.) [9]
The primary component, υ Carinae A, has a stellar classification of A8 Ib, making it a supergiant star that has exhausted the hydrogen at its core and evolved away from its brief main sequence lifetime as an O9 V star. [4] With an apparent magnitude of +3.08, [3] it has an effective temperature of about 7,600 K, [4] giving it a white hue. The companion, υ Carinae B, is a giant star with a classification of B7 III, [3] although Mandrini and Niemela (1986) suggested it may be a subgiant star with a classification of B4–5 IV. [4] The outer envelope of this star has an effective temperature of around 23,000 K, resulting in the blue-white hue of a B-type star.
The two stars have an angular separation of 5.030 arcseconds. As a binary star system, they would have an estimated orbital period of at least 19,500 years and a present-day separation of around 2,000 Astronomical Units. [4] This system is roughly 12 million years old. [6]
In the next 7500 years, the south Celestial pole will pass close to these stars and Iota Carinae (8100 CE). [10]