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Eta Gruis - HD215369 - HIP112374

Eta Gruis is a orange to red subgiant star that can be located in the constellation of Grus. Eta Gruis is the Bayer Classification for the star. HIP112374 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD215369.

Location of Eta 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 Eta Gruis, the location is 22h 45m 37.85 and -53d30`00.6 .

Proper Motion of Eta 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 017.37 ± 000.15 towards the north and 030.59 ± 000.23 east if we saw them in the horizon.

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

Eta Gruis has a spectral type of K2IIICNIV. This means the star is a orange to red subgiant star. The star has a B-V Colour Index of 1.18 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,524 Kelvin.

Eta Gruis has been calculated as 19.76 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 13,751,441.76.km.

Eta Gruis Apparent and Absolute Magnitudes

Eta Gruis has an apparent magnitude of 4.84 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 -0.57 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.68. 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 Eta Gruis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 8.27 which gave the calculated distance to Eta Gruis as 394.39 light years away from Earth or 120.92 parsecs. It would take a spaceship travelling at the speed of light, 394.39 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 7.86 which put Eta Gruis at a distance of 414.97 light years or 127.23 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.

Eta Gruis Facts

Alternative Names

Bayer DesignationEta Gruis
Hipparcos Library I.D.112374
Henry Draper Designation215369

Visual Facts

Star Typesubgiant star
Absolute Magnitude-0.57 / -0.68
Apparent Magnitude4.84
Right Ascension (R.A.)22h 45m 37.85
Declination (Dec.)-53d30`00.6
1997 Distance from Earth8.27 Parallax (milliarcseconds)
 394.39 Light Years
 120.92 Parsecs
2007 Revised Distance from Earth7.86 Parallax (milliarcseconds)
 414.97 Light Years
 127.23 Parsecs
Proper Motion Dec.17.37 ± 0.15 milliarcseconds/year
Proper Motion RA.30.59 ± 0.23 milliarcseconds/year
B-V Index1.18
Spectral TypeK2IIICNIV
Colour (K) Orange to Red

Estimated Facts

Radius (x the Sun)19.76
Calculated Effective Temperature4,524 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
215369-5410123.4A4.9000034.0000021.00000G8Yellow
B11.5000042.0000075.000001879

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