Canes Venatici Dwarf Galaxy [1] | |
---|---|
Observation data ( J2000 epoch) | |
Constellation | Canes Venatici |
Right ascension | 13h 28m 03.5s [1] |
Declination | +33° 33′ 21″ [1] |
Distance | 711 ± 33
kly (218 ± 10
kpc) [2] 685+23 −16 kly (210+7 −5 kpc) [3] |
Apparent magnitude (V) | 13.9 ± 0.5 [4] |
Characteristics | |
Type | dSph |
Apparent size (V) | 17.8 ± 0.8′ [5] |
Other designations | |
CVn Dwarf Galaxy, [1] PGC 4689223 |
Canes Venatici I or CVn I is a dwarf spheroidal galaxy situated in the Canes Venatici constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. [4] It is one of the most distant known satellites of the Milky Way as of 2011 together with Leo I and Leo II. [4] The galaxy is located at a distance of about 220 kpc from the Sun and is moving away from the Sun at a velocity of about 31 km/s. [6] It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elliptical (ratio of axes ~ 2.5:1) shape with the half-light radius of about 550 pc. [4] [5]
CVn I is a relatively faint satellite of the Milky Way—its integrated luminosity is about 230,000 times that of the Sun (absolute visible magnitude of about −8.6). [5] However, its mass is about 27 million solar masses, which means that the galaxy's mass to light ratio is around 220. A high mass to light ratio implies that CVn I is predominately made up of dark matter. [6]
The stellar population of CVn I consists mainly of old stars formed more than 10 billion years ago. The metallicity of these old stars is also very low at [Fe/H] ≈ −2.08 ± 0.02, which means that they contain 110 times less heavy elements than the Sun. [7] There are also about 60 RR Lyrae stars. [3] The galaxy also contains a small fraction of younger (1–2 billion years old) more metal-rich ([Fe/H] ≈ −1.5) stars, which account for about 5% of its mass and 10% of its light. These younger stars are concentrated in the center of the galaxy. [2] There is currently no star formation in CVn I and the measurements have so far failed to detect neutral hydrogen in it—the upper limit is 30,000 solar masses. [8]
Canes Venatici Dwarf Galaxy [1] | |
---|---|
Observation data ( J2000 epoch) | |
Constellation | Canes Venatici |
Right ascension | 13h 28m 03.5s [1] |
Declination | +33° 33′ 21″ [1] |
Distance | 711 ± 33
kly (218 ± 10
kpc) [2] 685+23 −16 kly (210+7 −5 kpc) [3] |
Apparent magnitude (V) | 13.9 ± 0.5 [4] |
Characteristics | |
Type | dSph |
Apparent size (V) | 17.8 ± 0.8′ [5] |
Other designations | |
CVn Dwarf Galaxy, [1] PGC 4689223 |
Canes Venatici I or CVn I is a dwarf spheroidal galaxy situated in the Canes Venatici constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. [4] It is one of the most distant known satellites of the Milky Way as of 2011 together with Leo I and Leo II. [4] The galaxy is located at a distance of about 220 kpc from the Sun and is moving away from the Sun at a velocity of about 31 km/s. [6] It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an elliptical (ratio of axes ~ 2.5:1) shape with the half-light radius of about 550 pc. [4] [5]
CVn I is a relatively faint satellite of the Milky Way—its integrated luminosity is about 230,000 times that of the Sun (absolute visible magnitude of about −8.6). [5] However, its mass is about 27 million solar masses, which means that the galaxy's mass to light ratio is around 220. A high mass to light ratio implies that CVn I is predominately made up of dark matter. [6]
The stellar population of CVn I consists mainly of old stars formed more than 10 billion years ago. The metallicity of these old stars is also very low at [Fe/H] ≈ −2.08 ± 0.02, which means that they contain 110 times less heavy elements than the Sun. [7] There are also about 60 RR Lyrae stars. [3] The galaxy also contains a small fraction of younger (1–2 billion years old) more metal-rich ([Fe/H] ≈ −1.5) stars, which account for about 5% of its mass and 10% of its light. These younger stars are concentrated in the center of the galaxy. [2] There is currently no star formation in CVn I and the measurements have so far failed to detect neutral hydrogen in it—the upper limit is 30,000 solar masses. [8]