WR 46 is a Wolf-Rayet star that can be located in the constellation of Crux. WR 46 is the brightest star in Crux based on the Hipparcos 2007 apparent magnitude. The star can not be seen by the naked eye, you need a telescope to see it.
HIP58954 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD104994.
WR 46 has alternative name(s), DI_Cru.
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 WR 46, the location is 12h 05m 18.73 and -62d03`10.1 .
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 1.84 ± 1.42 miliarcseconds/year towards the north and -5.44 ± 1.89 miliarcseconds/year east if we saw them in the horizon.
WR 46 has a spectral type of WN3p. This means the star is a Wolf-Rayet star. The star has a B-V Colour Index of -0.03 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 11,122 Kelvin.
WR 46 Radius has been calculated as being 1.05 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 729,463.21.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 0.70. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.
WR 46 has an apparent magnitude of 10.83 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 1.90 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.78. 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 1.64 which gave the calculated distance to WR 46 as 1988.80 light years away from Earth or 609.76 parsecs. It would take a spaceship travelling at the speed of light, 1988.80 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 2.45 which put WR 46 at a distance of 1331.28 light years or 408.16 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. WR 46 brightness ranges from a magnitude of 11.000 to a magnitude of 11.000 over its variable period. The smaller the magnitude, the brighter the star.
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.
|Traditional/Proper Name||WR 46|
|Short Name||DI Cru|
|Hipparcos Library I.D.||58954|
|Henry Draper Designation||104994|
|Star Type||Wolf-Rayet star|
|Absolute Magnitude||1.90 / 2.78|
|Visual / Apparent Magnitude||10.83|
|Naked Eye Visible||Requires a 4.5 - 6 Inch Telescope - Magnitudes|
|Right Ascension (R.A.)||12h 05m 18.73|
|Galactic Latitude||0.34 degrees|
|Galactic Longitude||297.56 degrees|
|1997 Distance from Earth||1.64 Parallax (milliarcseconds)|
|1988.80 Light Years|
|2007 Revised Distance from Earth||2.45 Parallax (milliarcseconds)|
|1331.28 Light Years|
|Proper Motion Dec.||1.84 ± 1.42 milliarcseconds/year|
|Proper Motion RA.||-5.44 ± 1.89 milliarcseconds/year|
|Radial Velocity||4.00 ± 999.00 km/s|
|Calculated Effective Temperature||11,122 Kelvin|