Sigma Cassiopeiae
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 23h 59m 00.538s |
| Declination | +55° 45′ 17.74″ |
| Apparent magnitude (V) | +4.88 (5.01 + 7.24) |
| Characteristics | |
| Spectral type | B2 IV + B3 V |
| U−B color index | −0.82 |
| B−V color index | −0.07 |
| Variable type | β Cep? |
| Astrometry | |
| Radial velocity (Rv) | −12.6 km/s |
| Proper motion (μ) |
RA: 8.14 ± 0.34 mas/yr Dec.: −5.01 ± 0.32 mas/yr |
| Parallax (π) | 0.72 ± 0.43mas |
| Distance | approx. 5,000 ly (approx. 1,400 pc) |
| Absolute magnitude (MV) | −3.90 + −1.7 |
| Details | |
| A | |
| Mass | 12 M☉ |
| Radius | 11.3 R☉ |
| Luminosity | 25,000 L☉ |
| Surface gravity (log g) | 3.6 cgs |
| Temperature | 21,000 K |
| Rotational velocity (v sin i) | 170 km/s |
| Age | 15.8 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Sigma Cassiopeiae (σ Cas, σ Cassiopeiae) is a binary star in the constellation Cassiopeia. It is approximately 5000 light years from Earth and has a combined apparent magnitude of +4.88.
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.
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).
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