Upsilon Carinae
 Location of υ Carinae (circled) |
|
| 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[1] mas |
| Distance | approx. 1,400 ly (approx. 440 pc) |
| Absolute magnitude (MV) | −5.56 |
| 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 | 1.2 × 107[5] years |
| 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 | |
Upsilon Carinae (υ Car, 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.[7] Consequently, υ Carinae itself is known as 海石五 (Hǎi Dàn wǔ, English: the Fifth Star of Sea Rock.)[8]
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.[5]
In the next 7500 years, the south Celestial pole will pass close to this stars and Iota Carinae (8100 CE).[9]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 3.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 6.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 28 日
- ↑ http://myweb.tiscali.co.uk/moonkmft/Articles/Precession.html
