Universe Guide

HomeFactsConstellationsAquarius

7 G. Aqr - HD197954 - HIP102561

7 G. Aqr is a orange to red star that can be located in the constellation of Aquarius. HIP102561 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD197954. The Id of the star in the Gould Star Catalogue is 7. 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 7 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 7 G. Aqr, the location is 20h 47m 03.57 and -02d29`12.7 .

Proper Motion of 7 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 -020.22 ± 000.31 towards the north and -021.47 ± 000.58 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 7 G. Aqr

7 G. Aqr has a spectral type of K2. This means the star is a orange to red star. The star has a B-V Colour Index of 1.55 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,903 Kelvin.

7 G. Aqr has been calculated as 27.42 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 19,080,818.96.km.

7 G. Aqr Apparent and Absolute Magnitudes

7 G. Aqr has an apparent magnitude of 6.28 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 -0.64 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.61. 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 7 G. Aqr

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.14 which gave the calculated distance to 7 G. Aqr as 787.83 light years away from Earth or 241.55 parsecs. It would take a spaceship travelling at the speed of light, 787.83 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 4.18 which put 7 G. Aqr at a distance of 780.30 light years or 239.23 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. 7 G. Aqr brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

7 G. Aqr Facts

Alternative Names

Traditional Name7 G. Aqr
Hipparcos Library I.D.102561
Bonner DurchmusterungBD-03 5018
Gould I.D.7
Henry Draper Designation197954

Visual Facts

Star Type star
Absolute Magnitude-0.64 / -0.61
Apparent Magnitude6.28
Right Ascension (R.A.)20h 47m 03.57
Declination (Dec.)-02d29`12.7
1997 Distance from Earth4.14 Parallax (milliarcseconds)
 787.83 Light Years
 241.55 Parsecs
2007 Revised Distance from Earth4.18 Parallax (milliarcseconds)
 780.30 Light Years
 239.23 Parsecs
Proper Motion Dec.-20.22 ± 0.31 milliarcseconds/year
Proper Motion RA.-21.47 ± 0.58 milliarcseconds/year
B-V Index1.55
Spectral TypeK2
Colour(K) Orange to Red

Variable Star Details

Estimated Facts

Radius (x the Sun)27.42
Calculated Effective Temperature3,903 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars


Add a Comment


Name:
Email: (Optional)
Comment: