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Regor (Gamma Velorum) - HD68273 - HIP39953

Regor (Gamma Velorum) is a eclipsing binary system very luminous supergiant starWolf-Rayet star that can be located in the constellation of Vela. Gamma Velorum is the Bayer Classification for the star. HIP39953 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD68273. Regor has alternative name(s), gam02_Vel.

It is the nearest and brightest Wolf-Rayet star to our own Sun. It is one of only two Wolf-Rayet stars that can be seen with the naked eye. The other naked-eye Wolf Rayet is Theta Muscae. The star is a binary star with another star revolving but as only one of those stars is catalogued in Hipparcos therefore only one is detailed here. It is more appropriate to call this star Gamma2 Velorum.

Regor`s Name

Regor is an unofficial name which was created by American pioneer astronaut Gus Grissom. The star was to be used to help them navigate. Gus Grissom nicknamed the star Regor after fellow astronaut Roger Chaffee and after their deaths along with Edward White II on Jan 27th 1967, the name stuck. The star Gamma Cassiopeiae is sometime referred to as Navi which is Gus` middle name. The star Iota Ursae Majoris has an unofficial name of Dnoces after White. In addition to being known as Regor, it has a more traditional name of Suhail al Muhlif. Neither Regor nor Suhail al Muhlif are recognised by the International Astronomer Union (I.A.U.). Ref: One Min Astronomer.

Location of Regor

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 Regor, the location is 08h 09m 31.96 and -47d20`11.8 .

Wolf-Rayet Star

The star is a Wolf-Rayet, a rare type of star of which not many are known. These stars are extremely luminous and large compared to our Sun. They live fast and die hard in a matter of millions not billions of years like our Sun. They exhaust their hydrogen supplies, turning to other gasses and expand outwards with massive solar winds, moving a step closer in the stellar evolution towards their death in a super or hypernova explosion.

Proper Motion of Regor

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 10.43 ± 0.25 miliarcseconds/year towards the north and -6.07 ± 0.30 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Temperature, Radius) of Regor

Regor has a spectral type of WC8 + O9I. This means the star is a Wolf-Rayet star. The star has a B-V Colour Index of -0.14 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 16,194 Kelvin.

Regor has been calculated as 13.69 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 9,522,077.05.km.

Regor Apparent and Absolute Magnitudes

Regor has an apparent magnitude of 1.75 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 -5.31 If you used the 2007 Parallax value, you would get an absolute magnitude of -5.92. 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 Regor

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.88 which gave the calculated distance to Regor as 840.63 light years away from Earth or 257.73 parsecs. It would take a spaceship travelling at the speed of light, 840.63 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 2.92 which put Regor at a distance of 1117.00 light years or 342.47 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 Regor

The star is a eclipsing binary system Eruptive Wolf-Rayet 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. Regor brightness ranges from a magnitude of 2.000 to a magnitude of 2.000 over its variable period. The smaller the magnitude, the brighter the star.

Meteor Showers Radiating from near Regor

The Gamma Velids Meteor Shower radiants from a point near this star. The meteor shower runs typically between 1-17 Jan with a peak date of 5/8 Jan. The speed of a meteor in the shower is 33 Km/s.

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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Regor Facts

Alternative Names

Traditional/Proper NameRegor
Short Namegam02 Vel
Bayer DesignationGamma Velorum
Hipparcos Library I.D.39953
Henry Draper Designation68273
Wolf-Rayet Id11

Visual Facts

Star Type Wolf-Rayet star
Absolute Magnitude-5.31 / -5.92
Apparent Magnitude1.75
Right Ascension (R.A.)08h 09m 31.96
Declination (Dec.)-47d20`11.8
1997 Distance from Earth3.88 Parallax (milliarcseconds)
 840.63 Light Years
 257.73 Parsecs
2007 Revised Distance from Earth2.92 Parallax (milliarcseconds)
 1117.00 Light Years
 342.47 Parsecs
Proper Motion Dec.10.43 ± 0.25 milliarcseconds/year
Proper Motion RA.-6.07 ± 0.30 milliarcseconds/year
B-V Index-0.14
Spectral TypeWC8 + O9I

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeEruptive Wolf-Rayet

Estimated Facts

Radius (x the Sun)13.69
Calculated Effective Temperature16,194 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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
68273-46 3847.2A2.20000-6.000004.00000O9Blue
68243-46 3846.2B4.50000-6.000002.00000B3Blue/White1826
-46 3848.2C8.50000-7.000002.00000A0White1835
-46 3849.2D9.40000-2.00000-23.00000A0White1846
DE12.800001928

Location of Regor in Vela


Regor (Gamma Velorum) Location in Vela

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


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