Canes Venatici II

Canes Venatici II or CVn II is a dwarf spheroidal galaxy located at a distance of about 150 kpc from the Milky Way. It has an elliptical (ratio of axes ~ 2:1) shape with the half-light radius of about 74+14 −10pc.

CVn II is one of the smallest and faintest satellites of the Milky Way — its absolute visible magnitude of about −4.9 is much lower than the luminosity of a typical globular cluster. However, its mass is about 2.5 million stellar masses, which means that galaxy's mass to light ratio is around 340. A high mass to light ratio implies that CVn II is dominated by the dark matter.

The stellar population of CVn II consists mainly of old stars formed more than 12 billion years ago. The metallicity of these old stars is also very low at [Fe/H] ≈ −2.19 ± 0.58. The stars of CVn II were probably among the first stars to form in the Universe. Currently there is no star formation in CVn II. The measurement have so far failed to detect neutral hydrogen in it.