Tau1 Capricorni
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 20h 37m 21.20s |
| Declination | −15° 08′ 50.4″ |
| Apparent magnitude (V) | +6.76 |
| Characteristics | |
| Spectral type | K1 III |
| U−B color index | +1.23 |
| B−V color index | +1.26 |
| Astrometry | |
| Radial velocity (Rv) | 18.5 ± 3 km/s |
| Proper motion (μ) | RA: 61.508 mas/yr Dec.: −47.081 mas/yr |
| Parallax (π) | 4.3504±0.0229 mas |
| Distance | 750 ± 4 ly (230 ± 1 pc) |
| Absolute magnitude (MV) | −0.27 |
| Details | |
| Mass | 1.18 M☉ |
| Radius | 25 R☉ |
| Luminosity | 191 L☉ |
| Surface gravity (log g) | 1.81 cgs |
| Temperature | 4,272 K |
| Metallicity [Fe/H] | −0.02 dex |
| Other designations | |
| τ1 Cap, 13 Capricorni, 34 G. Capricorni, BD−15°5732, GC 28694, HD 196348, HIP 101751, SAO 163740 | |
| Database references | |
| SIMBAD | data |
Tau1 Capricorni (τ1 Cap, τ1 Capricorni) is a star in the constellation Capricornus. It has an apparent magnitude of 6.76, making it readily visible in binoculars, but not to the naked eye. Located approximately 750 light years from Earth, the star is receding with a heliocentric radial velocity of 18.5 km/s. Due to its location near the ecliptic, τ1 Cap can be occulted by the Moon and rarely planets.
τ1 Capricorni has a stellar classification of K1 III, indicating that it is an ageing K-type giant. At present it has 118% the mass of the Sun and an enlarged radius of 25 solar radii. It shines at 191 times the luminosity of the Sun from its photosphere at an effective temperature of 4272 K. τ1 Cap's metallicity – elements heavier than helium – is at solar level.