Universe Guide

HomeFactsConstellationsGrus

Mu2 Gruis - HD211202 - HIP109973

Mu2 Gruis is a white to yellow giant star that can be located in the constellation of Grus. Mu2 Gruis is the Bayer Classification for the star. HIP109973 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD211202.

Location of Mu2 Gruis

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 Mu2 Gruis, the location is 22h 16m 26.57 and -41d37`37.9 .

Proper Motion of Mu2 Gruis

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 -006.72 ± 000.51 towards the north and -012.57 ± 000.64 east if we saw them in the horizon.

Mu2 Gruis Luminosity

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 113.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Mu2 Gruis

Mu2 Gruis has a spectral type of G8III. This means the star is a white to yellow giant star. The star has a B-V Colour Index of 0.93 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,989 Kelvin.

Mu2 Gruis has been calculated as 8.73 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 6,072,299.23.km.

Mu2 Gruis Apparent and Absolute Magnitudes

Mu2 Gruis has an apparent magnitude of 5.11 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 0.78 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.56. 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 Mu2 Gruis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 13.61 which gave the calculated distance to Mu2 Gruis as 239.65 light years away from Earth or 73.48 parsecs. It would take a spaceship travelling at the speed of light, 239.65 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 12.29 which put Mu2 Gruis at a distance of 265.39 light years or 81.37 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.

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.

Mu2 Gruis Facts

Alternative Names

Bayer DesignationMu2 Gruis
Hipparcos Library I.D.109973
Henry Draper Designation211202

Visual Facts

Star Typegiant star
Absolute Magnitude0.78 / 0.56
Apparent Magnitude5.11
Right Ascension (R.A.)22h 16m 26.57
Declination (Dec.)-41d37`37.9
1997 Distance from Earth13.61 Parallax (milliarcseconds)
 239.65 Light Years
 73.48 Parsecs
2007 Revised Distance from Earth12.29 Parallax (milliarcseconds)
 265.39 Light Years
 81.37 Parsecs
Proper Motion Dec.-6.72 ± 0.51 milliarcseconds/year
Proper Motion RA.-12.57 ± 0.64 milliarcseconds/year
B-V Index0.93
Spectral TypeG8III
Colour(G) White to Yellow

Estimated Facts

Radius (x the Sun)8.73
Luminosity (x the Sun)113.0000000
Calculated Effective Temperature4,989 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars


Add a Comment


Name:
Email: (Optional)
Comment: