| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lupus |
| Right ascension | 14h26m 10.81378s[1] |
| Declination | −45° 22′ 45.4023″[1] |
| Apparent magnitude (V) | 4.34[2] (4.93 + 5.55)[3] |
| Characteristics | |
| Spectral type | F4 IV + A7:[3] |
| U−B color index | +0.16[2] |
| B−V color index | +0.43[2] |
| Astrometry | |
| Radial velocity (Rv) | −0.60±1.60[4] km/s |
| Proper motion (μ) | RA: +14.62[1] mas/yr Dec.: −7.33[1] mas/yr |
| Parallax (π) | 10.22 ± 0.31 mas[1] |
| Distance | 319 ± 10 ly (98 ± 3 pc) |
| Absolute magnitude (MV) | −0.62[5] |
| Orbit[6] | |
| Period (P) | 26.2 yr |
| Semi-major axis (a) | 0.125″ |
| Eccentricity (e) | 0.94 |
| Inclination (i) | 56.0° |
| Longitude of the node (Ω) | 175.7° |
| Periastron epoch (T) | 1969.1 |
| Argument of periastron (ω) (secondary) | 191.0° |
| Details | |
| Luminosity | 150[5] L☉ |
| Rotational velocity (v sin i) | 0[7] km/s |
| Other designations | |
τ2 Lup, CD−44° 9323, HD 126354, HIP 70576, HR 5396, SAO 224920.[8] | |
| Database references | |
| SIMBAD | data |
Tau2 Lupi, Latinized from τ2 Lup, is a binary star[3] system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.34.[2] Based upon an annual parallax shift of 10.22[1] mas as seen from Earth, it is located around 319 light years from the Sun. The two components orbit each other with a period of 26.2 years and a high eccentricity of 0.94.[6] The brighter component is a magnitude 4.93 subgiant star with a stellar classification of F4 IV. Its companion is an A-type star with visual magnitude 5.55 and class A7:.[3]
