Tau Cassiopeiae

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τ Cassiopeiae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cassiopeia
Right ascension 23h 47m 03.455s[1]
Declination +58° 39′ 07.16″[1]
Apparent magnitude (V) +4.88
Spectral type K1IIIa
U−B color index +1.05
B−V color index +1.11
Variable type none
Radial velocity (Rv) −21 km/s
Proper motion (μ) RA: 60.81 ± 0.19[1] mas/yr
Dec.: 56.47 ± 0.17[1] mas/yr
Parallax (π) 18.75 ± 0.20[1] mas
Distance 174 ± 2 ly
(53.3 ± 0.6 pc)
Absolute magnitude (MV) +1.26
Other designations
5 Cassiopeiae, HR 9008, HD 223165, BD+57°2804, FK5 3909, HIP 117301, SAO 35763
Database references
Map of the Bayer-designated stars in Cassiopeia. Tau Cassiopeiae is circled.

Tau Cassiopeiae (τ Cas, τ Cassiopeiae) is a star in the constellation Cassiopeia. τ Cassiopeiae is an orange K-type giant with an apparent magnitude of +4.88. It is approximately 174 light years from Earth.[1]


In Chinese, 螣蛇 (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of τ Cassiopeiae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, σ Cassiopeiae, ρ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, τ Cassiopeiae itself is known as 螣蛇十三 (Téng Shé shísān, English: the Thirteenth Star of Flying Serpent)[2]