Delta Velorum
Delta Velorum (δ Velorum, abbreviated Delta Vel, δ Vel) is a triple star system in the southern constellation of Vela, near the border with Carina, and is part of the False Cross. Based on parallax measurements, it is approximately 80.6 light-years (24.7 parsecs) from the Sun. It is one of the stars that at times lies near the south celestial pole due to precession.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela |
| δ Vel A | |
| Right ascension | 08h 44m 42.226s |
| Declination | −54° 42′ 31.76″ |
| Apparent magnitude (V) | 1.95 - 2.43 |
| δ Vel B | |
| Right ascension | 08h 44m 42.203s |
| Declination | −54° 42′ 30.60″ |
| Apparent magnitude (V) | 5.54 |
| Characteristics | |
| U−B color index | +0.07 |
| B−V color index | +0.04 |
| δ Vel A | |
| Spectral type | A1 Va(n) |
| Variable type | Algol |
| δ Vel B | |
| Spectral type | F7.5V |
| Astrometry | |
| Radial velocity (Rv) | +2.2 km/s |
| Proper motion (μ) | RA: +28.99 mas/yr Dec.: −103.35 mas/yr |
| Parallax (π) | 40.49 ± 0.39 mas |
| Distance | 80.6 ± 0.8 ly (24.7 ± 0.2 pc) |
| Absolute magnitude (MV) | 0.02/3.60 |
| Orbit | |
| Primary | δ Vel A |
| Companion | δ Vel B |
| Period (P) | 143.2 yr |
| Semi-major axis (a) | 1.996″ |
| Eccentricity (e) | 0.475 |
| Inclination (i) | 105.1° |
| Orbit | |
| Primary | δ Vel Aa |
| Companion | δ Vel Ab |
| Period (P) | 45.1503 days |
| Semi-major axis (a) | 0.01651″ |
| Eccentricity (e) | 0.287 |
| Inclination (i) | 89.04° |
| Details | |
| δ Vel Aa | |
| Mass | 2.43 M☉ |
| Radius | 2.79–2.97 R☉ |
| Luminosity | 67 L☉ |
| Surface gravity (log g) | 3.78–3.90 cgs |
| Temperature | 9,440 K |
| Metallicity [Fe/H] | −0.33 dex |
| Rotation | 1.05 days |
| Rotational velocity (v sin i) | 143.5 km/s |
| δ Vel Ab | |
| Mass | 2.27 M☉ |
| Radius | 2.37–2.52 R☉ |
| Luminosity | 51 L☉ |
| Surface gravity (log g) | 3.99–4.10 cgs |
| Temperature | 9,830 K |
| Metallicity [Fe/H] | −0.33 dex |
| Rotational velocity (v sin i) | 149.6 km/s |
| Age | 400 million years |
| δ Vel B | |
| Mass | 1.35–1.46 M☉ |
| Radius | 1.43 R☉ |
| Luminosity | 3.5 L☉ |
| Temperature | 6,600 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
δ Velorum consists of an eclipsing binary, designated Delta Velorum A, and a more distant third companion, Delta Velorum B. δ Velorum A's two components are themselves designated Aa (officially named Alsephina /ælsɪˈfaɪnə/, the traditional name for the entire system) and Ab.
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