AR Cassiopeiae
Encyclopedia
AR Cassiopeiae is a multiple star system in the constellation
of Cassiopeia
. It is thought to be a septuple star system. It is only one of two star system
s with a multiplicity of 7, the other being Nu Scorpii
, with no physical multiple star
s of greater multiplicity yet found.
The star was frequently referred to as IH Cas (or IH Cas) in literature. The origin of the designation "IH Cassiopeiae" is from the 17th century catalogue and constellation map by Johannes Hevelius
, which was kept in use due to the lack of a Flamsteed designation
or Bayer designation
for the star. It was the first star in Cassiopeia that Hevelius catalogued, thus "1 Hev. Cas" or "1 H. Cas" (similar to Gould designation
s), which becomes IH Cas through corruption.
The primary star of the system is Type-B and Class-IV
and sub component of the system is an Algol-type
eclipsing binary. The system is also considered a visual double star
.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
of Cassiopeia
Cassiopeia (constellation)
Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today...
. It is thought to be a septuple star system. It is only one of two star system
Star system
A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
s with a multiplicity of 7, the other being Nu Scorpii
Nu Scorpii
Nu Scorpii is a star system in the constellation Scorpius.It is at least a quintuple star, probably a septuple, consisting of two close groups that are separated by 41". The brighter group, Nu Scorpii A and B, is split by 1.3" and composed of spectral type B2 subgiants...
, with no physical multiple star
Multiple star
A multiple star consists of three or more stars which appear from the Earth to be close to one another in the sky. This may result from the stars being physically close and gravitationally bound to each other, in which case it is physical, or this closeness may be merely apparent, in which case...
s of greater multiplicity yet found.
The star was frequently referred to as IH Cas (or IH Cas) in literature. The origin of the designation "IH Cassiopeiae" is from the 17th century catalogue and constellation map by Johannes Hevelius
Johannes Hevelius
Johannes Hevelius Some sources refer to Hevelius as Polish:Some sources refer to Hevelius as German:*Encyplopedia Britannica * of the Royal Society was a councilor and mayor of Danzig , Pomeranian Voivodeship, in the Polish-Lithuanian Commonwealth...
, which was kept in use due to the lack of a Flamsteed designation
Flamsteed designation
Flamsteed designations for stars are similar to Bayer designations, except that they use numbers instead of Greek letters. Each star is assigned a number and the Latin genitive of the constellation it lies in...
or Bayer designation
Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name...
for the star. It was the first star in Cassiopeia that Hevelius catalogued, thus "1 Hev. Cas" or "1 H. Cas" (similar to Gould designation
Gould designation
Gould designations for stars are similar to Flamsteed designations in the way that they number stars within a constellation in increasing order of right ascension. Each star is assigned an integer , followed by " G. " , and then the Latin genitive of the constellation it lies in...
s), which becomes IH Cas through corruption.
The primary star of the system is Type-B and Class-IV
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
and sub component of the system is an Algol-type
Algol variable
Algol variables or Algol-type binaries are a class of eclipsing binary stars where the orbital plane of the stars are coincident with the line of sight from Earth. When the cooler component passes in front of the hotter one, part of the latter's light is blocked, and the total brightness of the...
eclipsing binary. The system is also considered a visual double star
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
.