Tau Cassiopeiae

τ Cassiopeiae
Location of τ Cassiopeiae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cassiopeia
Right ascension 23h 47m 03.39s
Declination +58° 39 06.7
Apparent magnitude (V) +4.86
Characteristics
Spectral type K1 IIIa
U−B color index +1.05
B−V color index +1.11
Variable type Suspected
Astrometry
Radial velocity (Rv)−20.48±0.31 km/s
Proper motion (μ) RA: +60.81±0.19 mas/yr
Dec.: +56.47±0.17 mas/yr
Parallax (π)18.75±0.20 mas
Distance174 ± 2 ly
(53.3 ± 0.6 pc)
Absolute magnitude (MV)1.269
Details
Mass1.44 M
Radius10 R
Luminosity40 L
Surface gravity (log g)2.50±0.09 cgs
Temperature4,617±77 K
Metallicity [Fe/H]+0.06±0.06 dex
Rotational velocity (v sin i)5.9 km/s
Age3.90 Gyr
Other designations
τ Cas, 5 Cas, BD+57°2804, FK5 3909, HD 223165, HIP 117301, HR 9008, SAO 35763
Database references
SIMBADdata

Tau Cassiopeiae (τ Cassiopeiae) is a solitary, orange hued star in the northern constellation of Cassiopeia. It is bright enough to be seen with the naked eye, having an apparent visual magnitude of +4.86. Based upon an annual parallax shift of 18.75 mas as seen from Earth, this system is located about 174 light years from the Sun.

The spectrum of this star indicates it is an evolved, K-type giant star with a stellar classification of K1 IIIa. It is a suspected variable star of unknown type. Tau Cassiopeiae is 3.9 billion years old with about 1.44 times the mass of the Sun and 10 times the Sun's radius. It is radiating 40 times the Sun's luminosity from its expanded photosphere at an effective temperature of around 4,617 K.