Universe Guide

100 G. Cen - HD105920 - HIP59439

100 G. Cen is a white to yellow giant star that can be located in the constellation of Centaurus. HIP59439 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD105920. The Id of the star in the Gould Star Catalogue is 100. 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.

Location of 100 G. Cen

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 100 G. Cen, the location is 12h 11m 31.67 and -51d21`33.0 .

Proper Motion of 100 G. Cen

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 -062.82 ± 000.30 towards the north and -199.11 ± 000.48 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 100 G. Cen

100 G. Cen has a spectral type of G6III+.... This means the star is a white to yellow coloured giant star. The star has a B-V Colour Index of 0.81 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,261 Kelvin.

100 G. Cen has been calculated as 3.41 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,372,606.96.km.

100 G. Cen Apparent and Absolute Magnitudes

100 G. Cen has an apparent magnitude of 6.23 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 2.59 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.63. 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 100 G. Cen

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 18.73 which gave the calculated distance to 100 G. Cen as 174.14 light years away from Earth or 53.39 parsecs. In 2007, Hipparcos data was revised with a new parallax of 19.02 which put 100 G. Cen at a distance of 171.48 light years or 52.58 parsecs.

It would take a spaceship travelling at the speed of light, 174.14 years using the 1997 distance to get there. We don't have the technology or spaceship that can carry people over that distance yet.

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.

100 G. Cen Facts

Traditional Name100 G. Cen
Hipparcos Library I.D.59439
Gould I.D.100
Henry Draper Designation105920
Celestial TypeStar
Absolute Magnitude2.59 / 2.63
Apparent Magnitude6.23
Right Ascension (R.A.)12h 11m 31.67
Declination (Dec.)-51d21`33.0
1997 Distance from Earth18.73 Parallax (milliarcseconds)
 174.14 Light Years
 53.39 Parsecs
2007 Distance from Earth19.02 Parallax (milliarcseconds)
 171.48 Light Years
 52.58 Parsecs
Proper Motion Dec.-62.82 ± 0.30 milliarcseconds/year
Proper Motion RA.-199.11 ± 0.48 milliarcseconds/year
B-V Index0.81
Spectral TypeG6III+...
Colour(G) White to Yellow
Star Typegiant star
Radius (x the Sun)3.41
Calculated Effective Temperature5,261 Kelvin

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