V357 Carinae
Binary star in the constellation Carina. From Wikipedia, the free encyclopedia
V357 Carinae (a Car, a Carinae)[n 1] is an astrometric and spectroscopic binary in the constellation Carina. It is approximately 419 light years from Earth. The mean apparent magnitude of the system is +3.43. Outside of brightly-lit urban areas, it is easily visible to the naked eye. The star appears 46.0' (0.7668°) ENE of Iota Carinae at the heart of the asterism and constellation which is skewed in having bulk of the stars away from the eastern, Canopus prow of the ship and close to the imagined sails of the ship, Vela.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Carina |
| Right ascension | 09h 10m 58.086s[1] |
| Declination | −58° 58′ 0.82″[1] |
| Apparent magnitude (V) | +3.41 - 3.44[2] |
| Characteristics | |
| Spectral type | B2IV-V[3] |
| Variable type | Eclipsing[2] |
| Astrometry | |
| Radial velocity (Rv) | 23.3[4] km/s |
| Proper motion (μ) | RA: −16.64[1] mas/yr Dec.: 15.00 mas/yr |
| Parallax (π) | 7.30 ± 0.35 mas[1] |
| Distance | 450 ± 20 ly (137 ± 7 pc) |
| Orbit[5] | |
| Period (P) | 6.74469 d |
| Eccentricity (e) | 0.18 |
| Semi-amplitude (K1) (primary) | 21.5 km/s |
| Details | |
| Aa1 | |
| Mass | 9.15[6] M☉ |
| Radius | 5.0[7] R☉ |
| Surface gravity (log g) | 4.0[7] cgs |
| Temperature | 21,744[7] K |
| Age | 18.7[8] Myr |
| Aa2 | |
| Mass | 1.10[6] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Properties
In 1959, Sergei Illarionovich Gaposchkin announced his discovery that the star, then known as a Carinae, is a variable star.[10] It was given its variable star designation, V357 Carinae, in 1977.[11] The star's brightness varies from magnitude +3.41 to +3.44 with a period of 6.74 days, which is its orbital period. It was classified as an eclipsing binary in Gaposchkin's original catalogue of variable stars,[11] although the variability was often considered doubtful.[3] It is now thought most likely to be a very shallow eclipsing binary.[2]
V357 Carinae is an astrometric binary, meaning its motion in the sky implies orbital motion about an invisible companion. It is also a single-lined spectroscopic binary, and possibly a triple system.[12] The two closest components orbit each other in 6.74 days, while the observed astrometric motion is much longer.[6]
Notes
- Pronounced: lower-case /eɪ/ /ˈkærɪnaɪ/ or /kæˈriːnaɪ/
References
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