| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Tucana |
| Right ascension | 0h 20m 39.03682s[1] |
| Declination | −69° 37′ 29.6821″[1] |
| Apparent magnitude (V) | +5.49[2] |
| Characteristics | |
| Spectral type | B9 V[3] |
| U−Bcolor index | −0.11[2] |
| B−Vcolor index | −0.05[2] |
| Astrometry | |
| Radial velocity (Rv) | +10.50±2.60[4] km/s |
| Proper motion (μ) | RA: −3.53[1]mas/yr Dec.: −0.10[1]mas/yr |
| Parallax (π) | 10.25±0.21 mas[1] |
| Distance | 318 ± 7 ly (98 ± 2 pc) |
| Absolute magnitude (MV) | +0.57[5] |
| Details | |
| π Tuc A | |
| Mass | 2.8+0.21 −0.18[6] M☉ |
| Luminosity | 59[7] L☉ |
| Surface gravity (log g) | 4.0±0.14[6] cgs |
| Temperature | 11,393±387[6] K |
| Rotational velocity (v sin i) | 236[8] km/s |
| Age | 206+48 −79[6] Myr |
| π Tuc B | |
| Mass | 0.60[5] M☉ |
| Radius | 0.553[5][a] R☉ |
| Luminosity | 0.063[5] L☉ |
| Temperature | 3,890[5] K |
| Other designations | |
| π Tuc,CPD−70°12,FK5 2018,HD 1685,HIP 1647,HR 83,SAO 248167[9] | |
| Database references | |
| SIMBAD | data |
Pi Tucanae (π Tuc, π Tucanae) is adouble star[5] in the southernconstellation ofTucana. It is visible to the naked eye with a combinedapparent visual magnitude of +5.49.[2] Based upon an annualparallax shift of 10.25 mas as seen from Earth, it is located around 317 light years from theSun.
The brighter star, component A, is aB-type main sequence star with astellar classification of B9 V.[3] At an age of about 206 million years,[6] it is spinning rapidly with aprojected rotational velocity of 236.[8] The star has an estimated 2.8[6] times themass of the Sun and radiates 59[7] times thesolar luminosity from itsphotosphere at aneffective temperature of 11,393 K.[6]
There is a nearby visual companion, component B, but the two stars may not form a physical pair. This star has aK-band magnitude of 10.1 and is a source ofX-ray emission. It has 60% of the Sun's mass and just 6.3% of the Sun's luminosity, with an effective temperature of 3,890 K.[5] The pair have an angular separation of 2.28 arc seconds along aposition angle of 211.4°, which corresponds to aprojected separation of 214.1 AU.[5]
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