48 Cassiopeiae
Encyclopedia
48 Cassiopeiae is a star system
in the constellation
Cassiopeia
. It is approximately 116.9 light years from Earth
.
The primary component, 48 Cassiopeiae A, is a white A-type
subgiant with an apparent magnitude
of +4.71. It has an astrometric companion, 48 Cassiopeiae B, which is a F-type
main sequence dwarf
with an apparent magnitude of +6.41. These two stars orbit around their common centre of mass once every 60.5 years. Component B has a semi-major axis
of 0.62 arcseconds, or 22 AU
. A third companion, 48 Cassiopeiae C, is a fourteenth magnitude star located 24 arcseconds, or at least 850 AU, away. The primary is also a spectroscopic binary, and has an unresolved companion, meaning the system has at least four components.
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...
in the constellation
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....
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 approximately 116.9 light years from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
The primary component, 48 Cassiopeiae A, is a white A-type
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...
subgiant with an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of +4.71. It has an astrometric companion, 48 Cassiopeiae B, which is a F-type
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...
main sequence dwarf
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
with an apparent magnitude of +6.41. These two stars orbit around their common centre of mass once every 60.5 years. Component B has a semi-major axis
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
of 0.62 arcseconds, or 22 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
. A third companion, 48 Cassiopeiae C, is a fourteenth magnitude star located 24 arcseconds, or at least 850 AU, away. The primary is also a spectroscopic binary, and has an unresolved companion, meaning the system has at least four components.