Leo V (dwarf galaxy)
Encyclopedia
Leo V is a dwarf spheroidal galaxy
situated in the Leo constellation and discovered in 2007 in the data obtained by Sloan Digital Sky Survey
. The galaxy is located at the distance of about 180 kpc from the Sun and moves away from the Sun with the velocity of about 173 km/s. It is classified as a dwarf spheroidal galaxy
(dSph) meaning that it has an approximately spherical shape with the half-light radius
of about 130 pc.
Leo V is one of the smallest and fainest satellites of the Milky Way
—its integrated luminosity is about 10,000 times that of the Sun (absolute visible magnitude of about ), which is much lower than the luminosity of a typical globular cluster
. However, its mass is about 330 thousands solar mass
es, which means that Leo's V mass to light ratio
is around 75. A relatively high mass to light ratio implies that Leo V is dominated by the dark matter
. The stellar population of Leo V consists mainly of old stars formed more than 12 billion years ago. The metallicity of these stars is also very low at , which means that they contain 100 times less heavy elements than the Sun.
The galaxy is located only 3 degrees away from another Milky Way's satellite, Leo IV
. The latter is also closer to the Sun by 20 kpc. These two galaxies may be physically associated with each other. There is evidence that they are connected by a star bridge.
Dwarf spheroidal galaxy
Dwarf spheroidal galaxy is a term in astronomy applied to low luminosity galaxies that are companions to the Milky Way and to the similar systems that are companions to the Andromeda Galaxy M31...
situated in the Leo constellation and discovered in 2007 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...
. The galaxy is located at the distance of about 180 kpc from the Sun and moves away from the Sun with the velocity of about 173 km/s. It is classified as a dwarf spheroidal galaxy
Dwarf spheroidal galaxy
Dwarf spheroidal galaxy is a term in astronomy applied to low luminosity galaxies that are companions to the Milky Way and to the similar systems that are companions to the Andromeda Galaxy M31...
(dSph) meaning that it has an approximately spherical shape with the half-light radius
Effective radius
The effective radius of a galaxy is the radius at which one half of the total light of the system is emitted interior to this radius. This assumes the galaxy is circularly symmetric...
of about 130 pc.
Leo V is one of the smallest and fainest satellites 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...
—its integrated luminosity is about 10,000 times that of the Sun (absolute visible magnitude of about ), which is much lower than the luminosity of a typical 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...
. However, its mass is about 330 thousands solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
es, which means that Leo's V mass to light ratio
Mass to light ratio
In astrophysics and physical cosmology the mass to light ratio, normally designated with the symbol \Upsilon is the quotient between the total mass of a spatial volume and its luminosity...
is around 75. A relatively high mass to light ratio implies that Leo V is dominated by the dark matter
Dark matter
In astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...
. The stellar population of Leo V consists mainly of old stars formed more than 12 billion years ago. The metallicity of these stars is also very low at , which means that they contain 100 times less heavy elements than the Sun.
The galaxy is located only 3 degrees away from another Milky Way's satellite, Leo IV
Leo IV (dwarf galaxy)
Leo IV is a dwarf spheroidal galaxy situated in the Leo constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. The galaxy is located at the distance of about 160 kpc from the Sun and moves away from the Sun with the velocity of about 130 km/s...
. The latter is also closer to the Sun by 20 kpc. These two galaxies may be physically associated with each other. There is evidence that they are connected by a star bridge.