Segue 3
Encyclopedia
Segue 3 is a faint star cluster
of the Milky Way
galaxy discovered in 2010 in the data obtained by Sloan Digital Sky Survey
. It is located in the Pegasus constellation at the distance of about 17 kpc from the Sun and moves away from it with the velocity of .
Segue 3 is extremely faint—its visible absolute magnitude
is estimated at −1.2 or even at about , which means that the cluster is only 100 to 250 times brighter than the Sun. Its small radius—of about 2.1 pc—is typical for the galactic globular cluster
s. The cluster has a slightly flattened shape and shows some evidence of the tidal disruption.
The metallicity of Segue's 3 stars is , which means that they contain 70 times less heavy elements than the Sun. These stars are more than 12 billion year old. Segue 3 appears to be one of the fainest globular clusters of the Milky Way.
Star cluster
Star clusters or star clouds are groups of stars. Two types of star clusters can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars which are gravitationally bound, while open clusters, more loosely clustered groups of stars, generally contain less than...
of 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...
galaxy discovered in 2010 in the data obtained by Sloan Digital Sky Survey
Sloan Digital Sky Survey
The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...
. It is located in the Pegasus constellation at the distance of about 17 kpc from the Sun and moves away from it with the velocity of .
Segue 3 is extremely faint—its visible absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
is estimated at −1.2 or even at about , which means that the cluster is only 100 to 250 times brighter than the Sun. Its small radius—of about 2.1 pc—is typical for the galactic globular cluster
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
s. The cluster has a slightly flattened shape and shows some evidence of the tidal disruption.
The metallicity of Segue's 3 stars is , which means that they contain 70 times less heavy elements than the Sun. These stars are more than 12 billion year old. Segue 3 appears to be one of the fainest globular clusters of the Milky Way.