Sigma Cassiopeiae (σ Cas, σ Cassiopeiae) is a binary star in the constellation Cassiopeia. It is approximately 1520 light years from Earth and is 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, π Cygni, π 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)