Universe Guide

HomeFactsConstellationsCanes Venatici

Cor Caroli, Alpha2 Canum Venaticorum, 12 Canum Venaticorum, HD112413, HIP63125, HR4915

Cor Caroli (Alpha2 Canum Venaticorum) is a blue rotating star that can be located in the constellation of CanesVenatici. Cor Caroli is the 1st brightest star in Canes Venatici based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Alpha2 Canum Venaticorum is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR4915. HIP63125 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD112413.

Cor Caroli has alternative name(s), alf02 CVn.

Location of Cor Caroli

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Cor Caroli, the location is 12h 56m 01.84 and +38d19`05.7 .

Proper Motion of Cor Caroli

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving 53.54 ± 0.55 miliarcseconds/year towards the north and -235.08 ± 0.90 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Cor Caroli

Cor Caroli has a spectral type of A0spe.... This means the star is a blue star. The star is 7403.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24145.8723563200000000s. The star has a B-V Colour Index of -0.11 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 14,384 Kelvin.

Cor Caroli Radius has been calculated as being 1.34 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 932,451.02.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.40. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Cor Caroli Apparent and Absolute Magnitudes

Cor Caroli has an apparent magnitude of 2.89 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of 0.25 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.16. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to Cor Caroli

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 29.60 which gave the calculated distance to Cor Caroli as 110.19 light years away from Earth or 33.78 parsecs. It would take a spaceship travelling at the speed of light, 110.19 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 28.41 which put Cor Caroli at a distance of 114.81 light years or 35.20 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

The star's Galacto-Centric Distance is 7,403.00 Parsecs or 24,145.87 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of Cor Caroli

The star is a rotating Alpha2 Canum Venaticorum variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. Cor Caroli brightness ranges from a magnitude of 2.893 to a magnitude of 2.828 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 5.5 days (variability).

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Cor Caroli Facts

Alternative Names

Traditional/Proper NameCor Caroli
Flamsteed Name12 Canum Venaticorum
Flamsteed Short Name12 CVn
Short Namealf02 CVn
Bayer DesignationAlpha2 Canum Venaticorum
Hipparcos Library I.D.63125
Yale Bright Star Catalogue (HR) Id4915
Bonner DurchmusterungBD+39 2580
Henry Draper Designation112413

Visual Facts

Star Type star
Absolute Magnitude0.25 / 0.16
Visual / Apparent Magnitude2.89
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)12h 56m 01.84
Declination (Dec.)+38d19`05.7
Galactic Latitude78.77 degrees
Galactic Longitude118.30 degrees
1997 Distance from Earth29.60 Parallax (milliarcseconds)
 110.19 Light Years
 33.78 Parsecs
2007 Revised Distance from Earth28.41 Parallax (milliarcseconds)
 114.81 Light Years
 35.20 Parsecs
Galacto-Centric Distance24,145.87 Light Years / 7,403.00 Parsecs
Proper Motion Dec.53.54 ± 0.55 milliarcseconds/year
Proper Motion RA.-235.08 ± 0.90 milliarcseconds/year
B-V Index-0.11
Radial Velocity-4.10 ± 0.20 km/s
Spectral TypeA0spe...
Colour(A) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeAlpha2 Canum Venaticorum
Mean Variability Period in Days5.470
Variable Magnitude Range (Brighter - Dimmer)2.828 - 2.893

Estimated Facts

Calculated Effective Temperature14,384 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Cor Caroli in Canes Venatici

Cor Caroli (Alpha2 Canum Venaticorum) Location in Canes Venatici

The map was generated using Night Vision, an awesome free application by Brian Simpson.

Add a Comment

Email: (Optional)