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Gamma Indi, HD203760, HIP105841, HR8188

Gamma Indi is a blue to white giant star that can be located in the constellation of Indus. The description is based on the spectral class. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it. The star has an estimated age of 1.30 Billion of Years but could be as young as 1.20 to 1.40 according to Hipparcos.

Gamma Indi's Alternative Names

Gamma Indi (Gam Ind) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR8188. HIP105841 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD203760.

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

Location of Gamma Indi

The location of the 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 star is compared to the celestial equator and is expressed in degrees. For Gamma Indi, the location is 21h 26m 15.44 and -54° 39` 38.0 .

Proper Motion of Gamma Indi

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 39.38 ± 0.22 miliarcseconds/year towards the north and 1.11 ± 0.36 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 10.40000 km/s with an error of about 0.60 km/s .

Gamma Indi 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 13.50 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature, Age) of Gamma Indi

Gamma Indi has a spectral type of F1III. This means the star is a blue to white giant star. The star is 7,354.00 Parsecs from the Galactic Centre or terms of Light Years is 23,986.05 s. The star has a B-V Colour Index of 0.36 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,918 Kelvin.

Gamma Indi Radius has been calculated as being 2.49 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,735,426.78.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 2.62. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is 0.04 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

The stars age according to Hipparcos data files put the star at an age of about 1.30 Billion years old but could be between 1.20 and 1.40 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

Gamma Indi Apparent and Absolute Magnitudes

Gamma Indi has an apparent magnitude of 6.10 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 2.08 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.97. 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 Gamma Indi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 15.68 which gave the calculated distance to Gamma Indi as 208.01 light years away from Earth or 63.78 parsecs. It would take a spaceship travelling at the speed of light, 208.01 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 14.96 which put Gamma Indi at a distance of 218.02 light years or 66.84 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 7,354.00 Parsecs or 23,986.05 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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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Gamma Indi Facts

Visual Facts

Primary / Proper / Traditional NameGamma Indi
Alternative NamesGam Ind, HD 203760, HIP 105841, HR 8188
Spectral TypeF1III
Multiple Star SystemNo / Unknown
Star TypeGiant Star
Colour blue to white
GalaxyMilky Way
Age1.30 Billion Years Old
Age Range1.20 - 1.40 Billion Years Old
Absolute Magnitude2.08 / 1.97
Visual / Apparent Magnitude6.10
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)21h 26m 15.44
Declination (Dec.)-54° 39` 38.0
Galactic Latitude-43.94 degrees
Galactic Longitude341.75 degrees
1997 Distance from Earth15.68 Parallax (milliarcseconds)
 208.01 Light Years
 63.78 Parsecs
2007 Distance from Earth14.96 Parallax (milliarcseconds)
 218.02 Light Years
 66.84 Parsecs
Galacto-Centric Distance23,986.05 Light Years / 7,354.00 Parsecs
Proper Motion Dec.39.38 ± 0.22 milliarcseconds/year
Proper Motion RA.1.11 ± 0.36 milliarcseconds/year
B-V Index0.36
Radial Velocity10.40 ± 0.60 km/s
Iron Abundance0.04 ± 9.99 Fe/H
Semi-Major Axis9440.00
Stellar Luminosity (Lsun)13.50

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Facts

Calculated Effective Temperature6,918 Kelvin

Sources and Links

SIMBAD SourceLink

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