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Gamma Sagittae - HD189319 - HIP98337

Gamma Sagittae is a orange to red giant star that can be located in the constellation of Sagitta. Gamma Sagittae is the Bayer Classification for the star. HIP98337 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD189319. Gamma Sagittae has alternative name(s), 12 Sagittae , 12 Sge.

Location of Gamma Sagittae

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 Gamma Sagittae, the location is 19h 58m 45.39 and +19d29`31.5 .

Proper Motion of Gamma Sagittae

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 022.22 ± 000.10 towards the north and 066.21 ± 000.18 east if we saw them in the horizon.

Gamma Sagittae 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 32.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Gamma Sagittae

Gamma Sagittae has a spectral type of K5III. This means the star is a orange to red giant star. The star has a B-V Colour Index of 1.57 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,850 Kelvin.

Gamma Sagittae has been calculated as 34.99 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 24,348,783.53.km.

Gamma Sagittae Apparent and Absolute Magnitudes

Gamma Sagittae has an apparent magnitude of 3.51 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 -1.11 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.98. 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 Sagittae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 11.90 which gave the calculated distance to Gamma Sagittae as 274.09 light years away from Earth or 84.03 parsecs. In 2007, Hipparcos data was revised with a new parallax of 12.62 which put Gamma Sagittae at a distance of 258.45 light years or 79.24 parsecs.

It would take a spaceship travelling at the speed of light, 274.09 years using the 1997 distance to get there. We don't have the technology or spaceship that can carry people over that distance yet.

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.

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Gamma Sagittae Facts

Alternative Names

Short Name12 Sge
Bayer DesignationGamma Sagittae
Alternative Name(s)12 Sagittae
Hipparcos Library I.D.98337
Bonner DurchmusterungBD+19 4229
Henry Draper Designation189319

Visual Facts

Star Typegiant star
Absolute Magnitude-1.11 / -0.98
Apparent Magnitude3.51
Right Ascension (R.A.)19h 58m 45.39
Declination (Dec.)+19d29`31.5
1997 Distance from Earth11.90 Parallax (milliarcseconds)
 274.09 Light Years
 84.03 Parsecs
2007 Distance from Earth12.62 Parallax (milliarcseconds)
 258.45 Light Years
 79.24 Parsecs
Proper Motion Dec.22.22 ± 0.10 milliarcseconds/year
Proper Motion RA.66.21 ± 0.18 milliarcseconds/year
B-V Index1.57
Spectral TypeK5III
Colour(K) Orange to Red

Estimated Facts

Radius (x the Sun)34.99
Luminosity (x the Sun)32.0000000
Calculated Effective Temperature3,850 Kelvin

Sources and Links

SIMBAD SourceLink


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