Canes Venatici II (dwarf galaxy)

The Canes Venatici - II Canes Venatici dwarf galaxy also briefly II is a dwarf spheroidal galaxy in the constellation of the hunting dogs. It was discovered in 2006 in imaging survey of the Sloan Digital Sky Survey. The galaxy is located at a distance of about 150 kpc to our solar system and moves to the Sun at a speed of 130 km / s. It has an ellipsoidal shape with a Achsverhältnisse of about 2:1 and a half-light radius of pc.

Properties

Luminosity

Canes Venatici II is one of the smallest and faintest satellite galaxies of our Milky Way. The integral luminosity corresponds to an absolute magnitude of MV = -4.9 m in about the 8,000 times the sun, which is less than the brightness of a typical globular cluster. Nevertheless, the dwarf galaxy has a total mass of about 2.5 million solar masses due to a high mass-luminosity ratio of 340. This implies a not untypical for this type of galaxy domination by dark matter.

Metallicity

The stellar population of Canes Venatici II consists mainly of older stars, which emerged more than 12 billion years ago. The metallicity of this aging generation of stars is correspondingly low with [Fe / H] = -2.19 ± 0.58, which means that they sometimes less in heavy elements has approximately 150 than the sun. The star of Canes Venatici II are thus probably the first stars ever to have formed in the universe. Currently holds this galaxy is no detectable star formation, the lower measurement limit of neutral hydrogen gas is 14,000 M ☉.