Kappa Tucanae
Kappa Tucanae, Latinised from, κ Tucanae, is a quadruple star system in the southern constellation Tucana. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of either +4.25 or +4.86, depending on the source. The system is located approximately 68 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +8 km/s.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Tucana |
| Right ascension | 01h 15m 46.16226s |
| Declination | −68° 52′ 33.3356″ |
| Apparent magnitude (V) | +4.25 or +4.86 (5.00 + 7.74 + 7.84 + 8.44) |
| Characteristics | |
| Spectral type | F6 IV + G5 V + K2V + ? |
| B−V color index | 0.48 |
| Astrometry | |
| Radial velocity (Rv) | +7.7±1.7 km/s |
| Proper motion (μ) | RA: +412.11 mas/yr Dec.: +127.74 mas/yr |
| Parallax (π) | 47.72 ± 0.41 mas |
| Distance | 68.3 ± 0.6 ly (21.0 ± 0.2 pc) |
| Absolute magnitude (MV) | 3.50 |
| Orbit | |
| Period (P) | 857.0 yr |
| Semi-major axis (a) | 5.960″ |
| Eccentricity (e) | 0.384 |
| Inclination (i) | 127.1° |
| Longitude of the node (Ω) | 10.3° |
| Periastron epoch (T) | 1763.50 |
| Argument of periastron (ω) (secondary) | 284.9° |
| Details | |
| κ Tuc A | |
| Mass | 1.37 M☉ |
| Temperature | 6,366 K |
| Rotational velocity (v sin i) | 61.1±3.1 km/s |
| κ Tuc B | |
| Mass | 0.85 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The system consists of two binary pairs separated by 5.3 arcminutes. The brightest star, Kappa Tucanae A, is a yellow-white F-type subgiant with an apparent magnitude of +5.0. Its binary companion, Kappa Tucanae B, has a magnitude of 7.74 and is located about 6″ away from the primary. It completes an orbit around the primary every 857 years.
The other binary pair, the magnitude +7.8 C, and the magnitude +8.4 D, are closer to one another, at 1.12 arcseconds, or at least 23 astronomical units. They orbit each other once every 86.2 years.