Sigma Cassiopeiae (σ Cas, σ Cassiopeiae) is a

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Cassiopeia Cassiopeia or Cassiopea may refer to: Greek mythology * Cassiopeia (mother of Andromeda), queen of Aethiopia and mother of Andromeda * Cassiopeia (wife of Phoenix), wife of Phoenix, king of Phoenicia * Cassiopeia, wife of Epaphus, king of Egy ...

. It is 1,200 to from

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

and has a combined

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

of +4.88, making it visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnification, magnifying, Optical telescope#Light-gathering power, light-collecting optical instrument, such as a telescope or microsc ...

. The primary component, σ Cassiopeiae A, is a B2

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution ...

with an

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

arcsecond A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

s apart.

Naming

Chinese Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethnic ...

, (), meaning '' Flying Serpent'', refers to an asterism consisting of σ Cassiopeiae, α Lacertae,

4 Lacertae 4 Lacertae is a single blue supergiant star in the northern constellation Lacerta, located about 2,600 light years away. This object visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.55. It is moving ...

, π² Cygni, π¹ Cygni,

HD 206267 HD 206267A is a hierarchical triple star system in the northern circumpolar constellation of Cepheus. Two of the members form a spectroscopic binary that orbit each other with a period of 3.7 days, while a third member lies further awa ...

ε Cephei Epsilon Cephei, Latinized from ε Cephei, is a star in the northern constellation of Cepheus. Based upon an annual parallax shift of 38.17 mas as seen from the Earth, it is located about 85 light years from the Sun. The star ...

, β Lacertae, ρ Cassiopeiae, τ Cassiopeiae,

AR Cassiopeiae AR Cassiopeiae (AR Cas) is a variable star in the constellation of Cassiopeia (constellation), Cassiopeia. It is thought to be a member of a multiple star system, septuple star system, one of only two known star systems with a multipl ...

9 Lacertae 9 Lacertae is a single star in the northern constellation Lacerta, located 172 light years away from Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.64. This object is moving furt ...

3 Andromedae 3 Andromedae, abbreviated 3 And, is a single star in the northern constellation of Andromeda. ''3 Andromedae'' is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.64. The distance to this ...

7 Andromedae 7 Andromedae, also named Honores, is a single, yellow-white hued star in the northern constellation of Andromeda. ''7 Andromedae'' is the Flamsteed designation, abbreviated 7 And. It is visible to the naked eye with an apparent visual m ...

8 Andromedae 8 Andromedae, abbreviated 8 And, is a probable triple star system in the northern constellation of Andromeda. ''8 Andromedae'' is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.82. Base ...

, λ Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, the

Chinese name Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethni ...

for σ Cassiopeiae itself is (, ).

References

{{Stars of Cassiopeia Cassiopeiae, Sigma Cassiopeiae, 08 Binary stars B-type giants B-type main-sequence stars Cassiopeia (constellation) 9071 224572 118243 Durchmusterung objects Beta Cephei variables Suspected variables