Universe Guide

GG Librae

GG Librae Facts

GG Librae's Alternative Names

HIP76075 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD138344.

GG Librae has alternative name(s) :- , GG Lib.

More details on objects' alternative names can be found at Star Names .

Location of GG Librae

The location of the giant 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 object is compared to the celestial equator and is expressed in degrees. For GG Librae, the location is 15h 32m 15.13 and -23° 52` 48.6 .

Proper Motion of GG Librae

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 -2.44 ± 0.34 milliarcseconds/year towards the north and 16.42 ± 0.77 milliarcseconds/year east if we saw them in the horizon. . 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.

Physical Properties (Colour, Temperature) of GG Librae

GG Librae Colour and Temperature

GG Librae has a spectral type of M4III. This means the star is a red giant star. The star has a B-V Colour Index of 1.48 which means the star's temperature is about 4,025 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu at being .

GG Librae Radius

Radius has been calculated as being 18.59 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 12,937,649.27.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 26.14. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

GG Librae Apparent and Absolute Magnitudes

GG Librae has an apparent magnitude of 6.75 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 0.07 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.67. 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 GG Librae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.62 which gave the calculated distance to GG Librae as 705.98 light years away from Earth or 216.45 parsecs. If you want that in miles, it is 473,441,927,741.

In 2007, Hipparcos data was revised with a new parallax of 3.28 which put GG Librae at a distance of 994.40 light years or 304.88 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.

Using the 2007 distance, the star is roughly 62,885,575.94 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

Travel Time to GG Librae

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A380736906,061,380.27
Speed of Sound (Mach 1)767.269869,136,086.40
Concorde (Mach 2)1,534.54434,567,476.82
New Horizons Probe33,00020,207,914.42
Speed of Light670,616,629.00994.40

Variable Type of GG Librae

The star is a pulsating Semi-Regular Star w 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. GG Librae brightness ranges from a magnitude of 6.726 to a magnitude of 6.501 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.2 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.

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Additional GG Librae Facts and Figures

Visual Facts

Primary / Proper / Traditional NameGG Librae
Alternative NamesHD 138344, HIP 76075, GG Lib
Spectral TypeM4III
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeGiant Star
GalaxyMilky Way
Absolute Magnitude 0.07 / -0.67
Visual / Apparent Magnitude6.75
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)15h 32m 15.13
Declination (Dec.)-23° 52` 48.6
Galactic Latitude25.91 degrees
Galactic Longitude343.94 degrees
1997 Distance from Earth4.62 Parallax (milliarcseconds)
 705.98 Light Years
 216.45 Parsecs
2007 Distance from Earth3.28 Parallax (milliarcseconds)
 994.40 Light Years
 304.88 Parsecs
 62,885,575.94 Astronomical Units
Proper Motion Dec.-2.44 ± 0.34 milliarcseconds/year
Proper Motion RA.16.42 ± 0.77 milliarcseconds/year
B-V Index1.48

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemi-Regular Star w
Mean Variability Period in Days0.189
Variable Magnitude Range (Brighter - Dimmer)6.501 - 6.726

Estimated Calculated Facts

Radius (x the Sun)26.14
Effective Temperature4,025 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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