Leo V (dwarf galaxy)

The Leo V dwarf galaxy, shortly Leo V is a spheroidal dwarf galaxy ( dSph ) in the constellation of Leo. It was discovered in 2007 based on data from the Sloan Digital Sky Survey. The galaxy is at a distance of about 180 kpc and away from our sun at a speed of around 173 km / s It has nearly spherical shape and has a half-light radius of approximately 130 pc.

Properties

Leo V is one of the smallest and faintest satellites of the Milky Way. The integral luminosity of the galaxy is about 10,000 times as large as that of the sun and is in absolute magnitude MV = ( -5.2 ± 0.4 ) mag ( other sources mention here also the value -4.3 mag and a smaller half-light radius of 40 pc, which would be less than that of a typical globular cluster ).

Nevertheless, the mass of Leo V is 330,000 solar masses, which leads to a mass-luminosity ratio of 75. This relatively high value implies a dominance of dark matter in this galaxy. The stellar population of the dwarf galaxy consists mainly of old stars that have formed more than 12 billion years ago. The metallicity of the galaxy is correspondingly low at [Fe / H] ≈ -2.0 ± 0.2, which is equivalent to the fact that they proportionately about 100 times less in heavy elements than the Sun has.

Leo V is only about 3 degrees away from another satellite galaxy of our Milky Way galaxy Leo IV. The latter is still 20 kpc closer to the Sun. There are indications that both galaxies are physically coupled and evidence of a link by stellar streams, a star bridge.