Sigma Cassiopeiae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
σ Cassiopeiae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cassiopeia
Right ascension 23h 59m 00.538s[1]
Declination +55° 45′ 17.74″[1]
Apparent magnitude (V) +4.88
Spectral type B1V
U−B color index −0.82
B−V color index −0.07
Variable type none
Radial velocity (Rv) −13 km/s
Proper motion (μ) RA: 8.14 ± 0.34[1] mas/yr
Dec.: −5.01 ± 0.32[1] mas/yr
Parallax (π) 0.72 ± 0.43[1] mas
Distance approx. 5,000 ly
(approx. 1,400 pc)
Absolute magnitude (MV) −3.46
Other designations
8 Cassiopeiae, HR 9071, HD 224572, BD+54°3082, HIP 118243, SAO 35947, ADS 17140, CCDM J23591+5546
Map of the Bayer-designated stars in Cassiopeia. Sigma Cassiopeiae is circled.

Sigma Cassiopeiae (σ Cas, σ Cassiopeiae) is a binary star in the constellation Cassiopeia. It is approximately 5000 light years from Earth[1] and has a combined apparent magnitude of +4.88.

The primary component, σ Cassiopeiae A, is a blue-white B-type giant with an apparent magnitude of +5.0. Its companion, σ Cassiopeiae B, is a blue-white B-type main sequence dwarf, with an apparent magnitude of +7.1. The two stars are 3.1 arcseconds apart.


In Chinese, 螣蛇 (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of σ Cassiopeiae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, σ Cassiopeiae itself is known as 螣蛇十一 (Téng Shé shíyī, English: the Eleventh Star of Flying Serpent)[2]