HD 5980
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Tucana |
| Right ascension | 00h 59m 26.569s |
| Declination | −72° 09′ 53.91″ |
| Apparent magnitude (V) | 8.8 - 11.9 |
| Characteristics | |
| Spectral type | LBV + WN4 + OI |
| U−B color index | −0.99 |
| B−V color index | −0.18 |
| Variable type | LBV and EA |
| Astrometry | |
| Radial velocity (Rv) | −20 km/s |
| Proper motion (μ) | RA: −3.5 mas/yr Dec.: −2.4 mas/yr |
| Distance | 200,000 ly (64,000 pc) |
| Absolute magnitude (MV) | −8.1 (−7.1/−6.8/−6.7) |
| Orbit | |
| Primary | HD 5980 A |
| Companion | HD 5980 B |
| Period (P) | 19.2656±0.0009 d |
| Semi-major axis (a) | 151±4 R☉ |
| Eccentricity (e) | 0.27±0.02 |
| Inclination (i) | 86° |
| Periastron epoch (T) | 2,451,424.97±0.25 |
| Argument of periastron (ω) (primary) | 134±4° |
| Semi-amplitude (K1) (primary) | 214±6 km/s |
| Semi-amplitude (K2) (secondary) | 200±6 km/s |
| Orbit | |
| Primary | HD 5980 C |
| Period (P) | 96.56±0.01 d |
| Eccentricity (e) | 0.815 |
| Periastron epoch (T) | 2451183.40±0.22 |
| Argument of periastron (ω) (primary) | 252±3.3° |
| Semi-amplitude (K2) (secondary) | 81±4 km/s |
| Details | |
| A | |
| Mass | 61 M☉ |
| Radius | 24 (21 – 280) R☉ |
| Luminosity | 2,200,000 (2,000,000 – 10,000,000) L☉ |
| Temperature | 45,000 (21,000 – 53,000) K |
| Metallicity [Fe/H] | −1.0 dex |
| Rotational velocity (v sin i) | 250 km/s |
| B | |
| Mass | 66 M☉ |
| Radius | 22 R☉ |
| Luminosity | 1,800,000 L☉ |
| Temperature | 45,000 K |
| Metallicity [Fe/H] | −1.0 dex |
| Rotational velocity (v sin i) | <400 km/s |
| Age | 2.6 Myr |
| C | |
| Mass | 34 M☉ |
| Radius | 24 R☉ |
| Luminosity | 708,000 L☉ |
| Temperature | 34,000 K |
| Metallicity [Fe/H] | ≅ −0.7 dex |
| Rotational velocity (v sin i) | 120 km/s |
| Age | 3.1 Myr |
| Other designations | |
| HD 5980, RMC 14, Sk 78, AB 5, SMC WR5, AAVSO 0056-72 | |
| Database references | |
| SIMBAD | data |
HD 5980 is a multiple star system on the outskirts of NGC 346 in the Small Magellanic Cloud (SMC) and is one of the brightest stars in the SMC.
HD 5980 has at least three components among the most luminous stars known: the unusual primary has a Wolf–Rayet spectrum and has produced a luminous blue variable (LBV) outburst; the secondary, also a Wolf–Rayet star, forms an eclipsing spectroscopic binary with the primary star; and a more distant O-type supergiant is also likely to be a binary.