Delta Velorum
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Vela |
| Right ascension | 08h 44m 42.2s |
| Declination | −54° 42′ 30″ |
| Apparent magnitude (V) | 1.95 (2.03/5.1) |
| Characteristics | |
| Spectral type | A1 V/G0 V |
| U−B color index | 0.06 |
| B−V color index | 0.04 |
| Variable type | Eclipsing binary |
| Astrometry | |
| Radial velocity (Rv) | +2.2 km/s |
| Proper motion (μ) | RA: 28.78 mas/yr Dec.: −104.14 mas/yr |
| Parallax (π) | 40.90 ± 0.38 mas |
| Distance | 79.7 ± 0.7 ly (24.4 ± 0.2 pc) |
| Absolute magnitude (MV) | −0.01 (0.05/3.51) |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta Velorum (δ Vel, δ Velorum) is a star system in the constellation Vela. It is approximately 79.7 light years from Earth. It is sometimes given the name Koo She, Chinese for 'Bow and Arrows', along with ω Velorum and stars in Canis Major.[1]
[edit] Components
The system appears to be composed of two sets of binary stars. The brightest of the four stars, δ Velorum A, is a white A-type main sequence dwarf with an apparent magnitude of +2.02. Its binary companion, δ Velorum B, has a magnitude of +5.1 and is separated from the A component by 2.6 arcseconds.
The second binary system is 69 arcseconds away. It is composed of the 11th magnitude δ Velorum C and the 13th magnitude δ Velorum D, which are 6 arcseconds apart.
In 1978 the principal component was reported to be a spectroscopic binary in the Proceeding of the Australian Astronomical observatory, and this was confirmed by the Hipparcos satellite. Observations of variability in the δ Velorum system were made independently by ground-based astronomers and the Galileo spaceprobe at Jupiter.[2] The star varies by about 30% every 45 days. Delta Velorum is the brightest known eclipsing binary, although Algol has a deeper minimum and is easier to observe visually. Only the principal component δ Velorum A is sufficiently bright to explain such variation. The system is now believed to consist of six stars: an eclipsing binary with nearby companions Aa and B, and two more distant stars, C and D.
Because of precession, δ Velorum will be the south polar star around 9000 AD.
[edit] Etymology
The Chinese name Koo She 弧矢 (Mandarin húshǐ) "Bow and Arrow", originally assigned for some stars among Canis Major, Puppis, and Vela, was introduced by Robson for this star.
[edit] References
- ^ Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning (Revised edition ed.). New York: Dover Publications. p. 73. ISBN 0486210790.
- ^ Otero, Fieseler & Lloyd (2000). Delta Velorum is an Eclisping Binary. IBVS 4999.[1]
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