Sigma Cassiopeiae

σ Cassiopeiae

Template:Location mark Location of σ Cassiopeiae (circled)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cassiopeia
σ Cas A
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	5.01
σ Cas B
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	7.24
Characteristics
σ Cas A
Spectral type	B2 IV
U−B Template:Engvar	−0.82
B−V Template:Engvar	−0.07
Variable type	β Cep
σ Cas B
Spectral type	B3 V
Astrometry
σ Cas A
Radial velocity (Rv)	−12.6 km/s
Proper motion (μ)	RA: +9.956 mas/yr Dec.: −4.492 mas/yr
Parallax (π)	2.7419±0.1491 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	−3.90
Radial velocity (Rv)	−5.0 km/s
Proper motion (μ)	RA: +8.651 mas/yr Dec.: −3.739 mas/yr
Parallax (π)	2.2572±0.0558 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	−1.7
Details
A
Mass	12 Template:Solar mass
Radius	11.3 Template:Solar radius
Luminosity	25,000 Template:Solar luminosity
Surface gravity (log g)	3.6 cgs
Temperature	21,000 K
Rotational velocity (v sin i)	170 km/s
Age	15.8 Myr
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
8 Cassiopeiae, HR 9071, HD 224572, BD+54°3082, HIP 118243, SAO 35947, ADS 17140, CCDM J23591+5546
Database references
SIMBAD	data

File:Sigma Cassiopeiae.jpg

σ Cassiopeiae in optical light

File:SigCasLightCurve.png

Light curves for Sigma Cassiopeiae, plotted from TESS data.

Sigma Cassiopeiae (σ Cas, σ Cassiopeiae) is a binary star in the constellation Cassiopeia. It is 1,200 to from Earth and has a combined apparent magnitude of +4.88, making it visible to the naked eye.

The primary component, σ Cassiopeiae A, is a B2 subgiant with an apparent magnitude of +5.0. Its companion, σ Cassiopeiae B, is a B5 main sequence dwarf with an apparent magnitude of +7.1. The two stars are three arcseconds apart.

Naming

In Chinese, (), 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, the Chinese name for σ Cassiopeiae itself is (, Template:Langx).