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Omicron2 Canis Majoris, 24 Canis Majoris, HD53138, HIP33977

Omicron2 Canis Majoris is a blue pulsating very luminous supergiant star that can be located in the constellation of CanisMajor. Omicron2 Canis Majoris is the brightest star in Canis Major 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.

Omicron2 Canis Majoris is the Bayer Classification for the star. HIP33977 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD53138.

Omicron2 Canis Majoris has alternative name(s), omi02 CMa.

Location of Omicron2 Canis Majoris

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 Omicron2 Canis Majoris, the location is 07h 03m 01.47 and -23d49`59.9 .

Proper Motion of Omicron2 Canis Majoris

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 3.61 ± 0.37 miliarcseconds/year towards the north and -2.21 ± 0.40 miliarcseconds/year east if we saw them in the horizon.

Omicron2 Canis Majoris Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 180000.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Omicron2 Canis Majoris

Omicron2 Canis Majoris has a spectral type of B3Ia. This means the star is a blue supergiant star. The star has a B-V Colour Index of -0.07 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,523 Kelvin.

Omicron2 Canis Majoris Radius has been calculated as being 38.86 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 27,041,731.13.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 41.84. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Omicron2 Canis Majoris Apparent and Absolute Magnitudes

Omicron2 Canis Majoris has an apparent magnitude of 3.02 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 -6.46 If you used the 2007 Parallax value, you would get an absolute magnitude of -6.62. 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 Omicron2 Canis Majoris

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.27 which gave the calculated distance to Omicron2 Canis Majoris as 2568.22 light years away from Earth or 787.40 parsecs. It would take a spaceship travelling at the speed of light, 2568.22 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 1.18 which put Omicron2 Canis Majoris at a distance of 2764.10 light years or 847.46 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.

Variable Type of Omicron2 Canis Majoris

The star is a pulsating Alpha Cygnus 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. Omicron2 Canis Majoris brightness ranges from a magnitude of 3.036 to a magnitude of 2.988 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 24.4 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.

Omicron2 Canis Majoris Facts

Alternative Names

Flamsteed Name24 Canis Majoris
Flamsteed Short Name24 CMa
Short Nameomi02 CMa
Bayer DesignationOmicron2 Canis Majoris
Hipparcos Library I.D.33977
Henry Draper Designation53138

Visual Facts

Star Typesupergiant star
Absolute Magnitude-6.46 / -6.62
Visual / Apparent Magnitude3.02
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)07h 03m 01.47
Declination (Dec.)-23d49`59.9
Galactic Latitude-8.23 degrees
Galactic Longitude235.55 degrees
1997 Distance from Earth1.27 Parallax (milliarcseconds)
 2568.22 Light Years
 787.40 Parsecs
2007 Revised Distance from Earth1.18 Parallax (milliarcseconds)
 2764.10 Light Years
 847.46 Parsecs
Proper Motion Dec.3.61 ± 0.37 milliarcseconds/year
Proper Motion RA.-2.21 ± 0.40 milliarcseconds/year
B-V Index-0.07
Radial Velocity48.40 ± 0.60 km/s
Spectral TypeB3Ia
Colour(B) blue

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeAlpha Cygnus
Mean Variability Period in Days24.440
Variable Magnitude Range (Brighter - Dimmer)2.988 - 3.036

Estimated Facts

Luminosity (x the Sun)180,000.0000000
Calculated Effective Temperature12,523 Kelvin

Sources and Links

SIMBAD SourceLink

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