Canes Venatici I (dwarf galaxy)

Canes Venatici I and CVn I is a spheroidal dwarf galaxy ( dSph ) in the constellation of the hunting dogs. It was discovered in 2006 in imaging survey of the Sloan Digital Sky Survey. It is as of 2011 one of the most distant satellite galaxies of our Milky Way, with Leo I and Leo II

The galaxy is about 220 kpc away from our solar system and has an escape velocity of approximately 31 km / s It has an axial ratio of 2.5 to 1 and a radius of the half-light of 550 pc.

Properties

Luminosity

CVn I is a relatively faint satellite of the Milky Way. The integral luminosity with its absolute magnitude of -8.6 m just 230,000 times that of the sun. In contrast, the total mass corresponds to approximately 27 million solar masses. For the dwarf galaxy comes to a mass-luminosity ratio of around 220 This high ratio is an indication of a strong dominance of dark matter in this galaxy.

Metallicity

The stellar population of CVn I is mainly dominated by old stars that emerged already 10 billion years ago. The metallicity of these old generation is also very low, with its [Fe / H] ≈ -2.08 ± 0.02. The sun contains about 110 times more compared to the heavy elements. CVn I contains about 60 RR Lyrae stars. The dwarf galaxy also contains a small proportion of younger stars at an age of about 1 to 2 billion years ago. This generation is characterized by a metallicity of [Fe / H] ≈ -1.5 from, makes up about 5 % of the mass and 10 % of the light from the galaxy and is concentrated to the center of the galaxy. Currently there are no star formation is noted in CVn I; it could now be no neutral hydrogen gas found ( upper limit thereof in about 30,000 solar masses ) in the measurements up.