SZ Crateris
Encyclopedia
SZ Crateris is a binary star
system. Both components belong to the main sequence
: the primary star has a spectral classification
of K5V while the secondary is a red dwarf
of spectral class M0V. The radius of the primary is about 66% the radius of the Sun, while the secondary member is only about 42% of the solar radius. In 1994, the two stars were separated by 5.1 arc seconds, which is equivalent to 112.41 astronomical unit
s.
SZ Crateris is classified as a marginal BY Draconis variable
, and has an optical variability cycle of 11.58 days. (The star causing the variability is unspecified.) Compared to the Sun, SZ Crateris has a slightly higher proportion of elements other than hydrogen and helium. Based upon gyrochronology
, the estimated age of this star is under 200 million years.
The SZ Crateris system is a member of the Ursa Major moving group
of stars that have similar motions through space. The space velocity components of this system are U = , V = and W = . It is on an orbit through the Milky Way
that has an orbital eccentricity of 0.092, which will bring it as close as 26.06 kly to the galactic core, and as distant as 31.31 kly. The inclination of the orbit carries the system as much as 0.352 kly from plane of the galactic disk.
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
system. Both components belong to the main sequence
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...
: the primary star has a spectral classification
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...
of K5V while the secondary is a red dwarf
Red dwarf
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
of spectral class M0V. The radius of the primary is about 66% the radius of the Sun, while the secondary member is only about 42% of the solar radius. In 1994, the two stars were separated by 5.1 arc seconds, which is equivalent to 112.41 astronomical unit
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
s.
SZ Crateris is classified as a marginal BY Draconis variable
BY Draconis variable
BY Draconis variables are main sequence variable stars of late spectral types, usually K or M. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in their luminosity due to rotation of the star coupled with star spots, and other...
, and has an optical variability cycle of 11.58 days. (The star causing the variability is unspecified.) Compared to the Sun, SZ Crateris has a slightly higher proportion of elements other than hydrogen and helium. Based upon gyrochronology
Gyrochronology
Gyrochronology is a method for deriving the age of a low-mass star like the Sun from its rotation period.The term is derived from the Greek words gyros, chronos and logos, roughly translated as rotation, age and study respectively....
, the estimated age of this star is under 200 million years.
The SZ Crateris system is a member of the Ursa Major moving group
Ursa Major Moving Group
The Ursa Major Moving Group, also known as Collinder 285 or Ursa Major association, is a nearby stellar moving group, a set of stars with common velocities in space and thought to have a common origin. Its core is located roughly 80 light years away...
of stars that have similar motions through space. The space velocity components of this system are U = , V = and W = . It is on an orbit through the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
that has an orbital eccentricity of 0.092, which will bring it as close as 26.06 kly to the galactic core, and as distant as 31.31 kly. The inclination of the orbit carries the system as much as 0.352 kly from plane of the galactic disk.