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HomeFactsConstellationsCanis Major

Unurgunite, Sigma Canis Majoris, 22 Canis Majoris, HD52877, HIP33856, HR2646

Unurgunite (Sigma Canis Majoris) is a orange to red pulsating giant star that can be located in the constellation of CanisMajor. The description is based on the spectral class. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Unurgunite's Alternative Names

Sigma Canis Majoris (Sig Cma) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR2646. HIP33856 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD52877.

Unurgunite has alternative name(s) :- , sig CMa.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 22 Canis Majoris with it shortened to 22 CMa.

More details on star alternative names can be found at Star Names .

Location of Unurgunite

The location of the star in the night sky 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 Unurgunite, the location is 07h 01m 43.15 and -27° 56` 05.4 .

Proper Motion of Unurgunite

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 4.59 ± 0.14 miliarcseconds/year towards the north and -5.98 ± 0.19 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 22.11000 km/s with an error of about 0.19 km/s .

Physical Properties (Colour, Temperature) of Unurgunite

Unurgunite has a spectral type of K4III. This means the star is a orange to red giant star. The star is 7,578.00 Parsecs from the Galactic Centre or terms of Light Years is 24,716.66 s. The star has a B-V Colour Index of 1.72 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,379 Kelvin.

Unurgunite Radius has been calculated as being 203.88 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 141,858,168.77.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 187.66. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -0.11 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Unurgunite Apparent and Absolute Magnitudes

Unurgunite has an apparent magnitude of 3.49 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 -4.37 If you used the 2007 Parallax value, you would get an absolute magnitude of -4.19. 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 Unurgunite

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.68 which gave the calculated distance to Unurgunite as 1217.03 light years away from Earth or 373.13 parsecs. It would take a spaceship travelling at the speed of light, 1217.03 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 2.91 which put Unurgunite at a distance of 1120.84 light years or 343.64 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 7,578.00 Parsecs or 24,716.66 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 Unurgunite

The star is a pulsating Slow Irregular 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. Unurgunite brightness ranges from a magnitude of 3.639 to a magnitude of 3.543 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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.

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Unurgunite Facts

Visual Facts


 Unurgunite
Alternative NamesSigma Canis Majoris, Sig Cma, HD 52877, HIP 33856, HR 2646, 22 Canis Majoris, 22 CMa, sig CMa
Spectral TypeK4III
Multiple Star SystemYes
Star TypeGiant Star
Colour orange to red
GalaxyMilky Way
ConstellationCanis Major
Absolute Magnitude-4.37 / -4.19
Visual / Apparent Magnitude3.49
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)07h 01m 43.15
Declination (Dec.)-27° 56` 05.4
Galactic Latitude-10.27 degrees
Galactic Longitude239.17 degrees
1997 Distance from Earth2.68 Parallax (milliarcseconds)
 1217.03 Light Years
 373.13 Parsecs
2007 Distance from Earth2.91 Parallax (milliarcseconds)
 1120.84 Light Years
 343.64 Parsecs
Galacto-Centric Distance24,716.66 Light Years / 7,578.00 Parsecs
Proper Motion Dec.4.59 ± 0.14 milliarcseconds/year
Proper Motion RA.-5.98 ± 0.19 milliarcseconds/year
B-V Index1.72
Radial Velocity22.11 ± 0.19 km/s
Iron Abundance-0.11 ± 9.99 Fe/H
Eccentricity0.05
Semi-Major Axis7909.00

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Variable Star ClassPulsating
Variable Star TypeSlow Irregular
Mean Variability Period in Days0.084
Variable Magnitude Range (Brighter - Dimmer)3.543 - 3.639

Estimated Facts


Calculated Effective Temperature3,379 Kelvin

Sources and Links


SIMBAD SourceLink

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
52877-27 3544.2A3.70000-8.000002.00000M0Red
B14.200001926

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