Regor (Gamma Velorum) is a eclipsing binary system wolf-rayet star that can be located in the constellation of Vela. The description is based on the spectral class. Regor is a main star of the constellation.
Regor is the 1st brightest star in Vela 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.
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 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.
Gamma Velorum (Gam02 Vel) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR3207. 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.
More details on star alternative names can be found at Star Names .
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 Regor, the location is 08h 09m 31.96 and -47° 20` 11.8 .
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.
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.
The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 15.00 km/s with an error of about 3.10 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.
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 64,399.63 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.
Regor has a spectral type of WC8 + O9I. The star is 7,457.00 Parsecs from the Galactic Centre or terms of Light Years is 24,322.00 s. 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 Radius has been calculated as being 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. 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 18.12. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.
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.
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.
The star's Galacto-Centric Distance is 7,457.00 Parsecs or 24,322.00 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.
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 1.724 to a magnitude of 1.680 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 days (variability).
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.
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.
|Primary / Proper / Traditional Name||Regor|
|Alternative Names||Gamma Velorum, Gam02 Vel, HD 68273, HIP 39953, HR 3207, gam02 Vel, WR 11|
|Spectral Type||WC8 + O9I|
|Constellation's Main Star||Yes|
|Multiple Star System||Yes|
|Star Type||very luminous Supergiant StarWolf-Rayet star|
|Absolute Magnitude||-5.31 / -5.92|
|Visual / Apparent Magnitude||1.75|
|Naked Eye Visible||Yes - Magnitudes|
|Right Ascension (R.A.)||08h 09m 31.96|
|Declination (Dec.)||-47° 20` 11.8|
|Galactic Latitude||-7.69 degrees|
|Galactic Longitude||262.80 degrees|
|1997 Distance from Earth||3.88 Parallax (milliarcseconds)|
|840.63 Light Years|
|2007 Distance from Earth||2.92 Parallax (milliarcseconds)|
|1117.00 Light Years|
|Galacto-Centric Distance||24,322.00 Light Years / 7,457.00 Parsecs|
|Proper Motion Dec.||10.43 ± 0.25 milliarcseconds/year|
|Proper Motion RA.||-6.07 ± 0.30 milliarcseconds/year|
|Radial Velocity||15.00 ± 3.10 km/s|
|Stellar Luminosity (Lsun)||64,399.63|
|Variable Star Class||Eclipsing binary system|
|Variable Star Type||Eruptive Wolf-Rayet|
|Mean Variability Period in Days||0.034|
|Variable Magnitude Range (Brighter - Dimmer)||1.680 - 1.724|
|Calculated Effective Temperature||16,194 Kelvin|
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. Id||B.D. Id||Star Code||Magnitude||R.A.||Dec.||Spectrum||Colour||Year|