Universe Guide


138 G. Aqr - HD212320 - HIP110532

138 G. Aqr is a white to yellow main sequence dwarf star that can be located in the constellation of Aquarius. HIP110532 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD212320. The Id of the star in the Gould Star Catalogue is 138. 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 138 G. Aqr

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 138 G. Aqr, the location is 22h 23m 32.15 and -07d11`40.0 .

Proper Motion of 138 G. Aqr

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 8.44 ± 0.44 miliarcseconds/year towards the north and -7.05 ± 0.64 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 138 G. Aqr

138 G. Aqr has a spectral type of G6V. This means the star is a white to yellow main sequence dwarf star. The star has a B-V Colour Index of 0.99 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,868 Kelvin.

138 G. Aqr has been calculated as 12.08 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 8,407,849.40.km.

138 G. Aqr Apparent and Absolute Magnitudes

138 G. Aqr has an apparent magnitude of 5.92 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 0.18 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.14. 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 138 G. Aqr

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.10 which gave the calculated distance to 138 G. Aqr as 459.38 light years away from Earth or 140.85 parsecs. It would take a spaceship travelling at the speed of light, 459.38 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 6.99 which put 138 G. Aqr at a distance of 466.61 light years or 143.06 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.

138 G. Aqr Facts

Alternative Names

Traditional/Proper Name138 G. Aqr
Hipparcos Library I.D.110532
Bonner DurchmusterungBD-07 5765
Gould I.D.138
Henry Draper Designation212320

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude0.18 / 0.14
Apparent Magnitude5.92
Right Ascension (R.A.)22h 23m 32.15
Declination (Dec.)-07d11`40.0
1997 Distance from Earth7.10 Parallax (milliarcseconds)
 459.38 Light Years
 140.85 Parsecs
2007 Revised Distance from Earth6.99 Parallax (milliarcseconds)
 466.61 Light Years
 143.06 Parsecs
Proper Motion Dec.8.44 ± 0.44 milliarcseconds/year
Proper Motion RA.-7.05 ± 0.64 milliarcseconds/year
B-V Index0.99
Spectral TypeG6V
Colour(G) White to Yellow

Estimated Facts

Radius (x the Sun)12.08
Calculated Effective Temperature4,868 Kelvin

Sources and Links

SIMBAD SourceLink

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