Universe Guide


Nu Centauri, HD120307, HIP67464

Nu Centauri is a blue eclipsing binary system subgiant star that can be located in the constellation of Centaurus. Nu Centauri is the brightest star in Centaurus 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.

Nu Centauri is the Bayer Classification for the star. HIP67464 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD120307. The Id of the star in the Gould Star Catalogue is 272. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major.

Nu Centauri has alternative name(s), nu. Cen.

Location of Nu Centauri

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 Nu Centauri, the location is 13h 49m 30.30 and -41d41`15.6 .

Proper Motion of Nu Centauri

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 -20.18 ± 0.09 miliarcseconds/year towards the north and -26.77 ± 0.17 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Nu Centauri

Nu Centauri has a spectral type of B2IV. This means the star is a blue subgiant star. The star is 7313.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23852.3253467200000000s. The star has a B-V Colour Index of -0.22 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 18,854 Kelvin.

Nu Centauri Radius has been calculated as being 2.66 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,847,585.24.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.43. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Nu Centauri Apparent and Absolute Magnitudes

Nu Centauri has an apparent magnitude of 3.41 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 -2.41 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.22. 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 Nu Centauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.87 which gave the calculated distance to Nu Centauri as 474.76 light years away from Earth or 145.56 parsecs. It would take a spaceship travelling at the speed of light, 474.76 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 7.47 which put Nu Centauri at a distance of 436.63 light years or 133.87 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 7,313.00 Parsecs or 23,852.33 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 Nu Centauri

The star is a eclipsing binary system Beta Lyrae (Sheliak) 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. Nu Centauri brightness ranges from a magnitude of 3.329 to a magnitude of 3.318 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 2.6 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.

Nu Centauri Facts

Alternative Names

Short Namenu. Cen
Bayer DesignationNu Centauri
Hipparcos Library I.D.67464
Gould I.D.272
Henry Draper Designation120307

Visual Facts

Star Typesubgiant star
Absolute Magnitude-2.41 / -2.22
Visual / Apparent Magnitude3.41
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)13h 49m 30.30
Declination (Dec.)-41d41`15.6
Galactic Latitude19.89 degrees
Galactic Longitude314.41 degrees
1997 Distance from Earth6.87 Parallax (milliarcseconds)
 474.76 Light Years
 145.56 Parsecs
2007 Revised Distance from Earth7.47 Parallax (milliarcseconds)
 436.63 Light Years
 133.87 Parsecs
Galacto-Centric Distance23,852.33 Light Years / 7,313.00 Parsecs
Proper Motion Dec.-20.18 ± 0.09 milliarcseconds/year
Proper Motion RA.-26.77 ± 0.17 milliarcseconds/year
B-V Index-0.22
Radial Velocity8.00 ± 2.00 km/s
Spectral TypeB2IV
Colour(B) blue

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeBeta Lyrae (Sheliak)
Mean Variability Period in Days2.625
Variable Magnitude Range (Brighter - Dimmer)3.318 - 3.329

Estimated Facts

Calculated Effective Temperature18,854 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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