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15 Geminorum, HD45352, HIP30757

15 Geminorum is a orange to red star that can be located in the constellation of Gemini. The star can not be seen by the naked eye, you need a telescope to see it.

HIP30757 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD45352.

Location of 15 Geminorum

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 15 Geminorum, the location is 06h 27m 46.58 and +20d 47` 22.6 .

Proper Motion of 15 Geminorum

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 -44.09 ± 0.65 miliarcseconds/year towards the north and -32.59 ± 1.19 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 -30.10000 km/s with an error of about 3.00 km/s .

Physical Properties (Colour, Temperature, Radius) of 15 Geminorum

15 Geminorum has a spectral type of K0. This means the star is a orange to red star. The star has a B-V Colour Index of 1.24 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,494 Kelvin.

15 Geminorum Radius has been calculated as being 13.35 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 9,292,202.18.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 13.05. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

15 Geminorum Apparent and Absolute Magnitudes

15 Geminorum has an apparent magnitude of 6.54 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 0.31 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.36. 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 15 Geminorum

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 5.67 which gave the calculated distance to 15 Geminorum as 575.24 light years away from Earth or 176.37 parsecs. It would take a spaceship travelling at the speed of light, 575.24 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 5.81 which put 15 Geminorum at a distance of 561.38 light years or 172.12 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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

15 Geminorum Facts

Alternative Names

Traditional/Proper Name15 Geminorum
Flamsteed Name15 Geminorum
Flamsteed Short Name15 Gem
Hipparcos Library I.D.30757
Bonner DurchmusterungBD+20 1427
Henry Draper Designation45352

Visual Facts

Star Type star
Absolute Magnitude0.31 / 0.36
Visual / Apparent Magnitude6.54
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)06h 27m 46.58
Declination (Dec.)+20d 47` 22.6
Galactic Latitude4.36 degrees
Galactic Longitude191.78 degrees
1997 Distance from Earth5.67 Parallax (milliarcseconds)
 575.24 Light Years
 176.37 Parsecs
2007 Revised Distance from Earth5.81 Parallax (milliarcseconds)
 561.38 Light Years
 172.12 Parsecs
Proper Motion Dec.-44.09 ± 0.65 milliarcseconds/year
Proper Motion RA.-32.59 ± 1.19 milliarcseconds/year
B-V Index1.24
Radial Velocity-30.10 ± 3.00 km/s
Spectral TypeK0
Colour(K) Orange to Red

Estimated Facts

Calculated Effective Temperature4,494 Kelvin

Sources and Links

SIMBAD SourceLink

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