Universe Guide


Gliese 251 - HD265866 - HIP33226

Gliese 251 is a orange to red star that can be located in the constellation of Gemini. HIP33226 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD265866.

Location of Gliese 251

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 Gliese 251, the location is 06h 54m 49.47 and +33d16`08.9 .

Proper Motion of Gliese 251

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 -398.40 ± 000.77 towards the north and -723.99 ± 001.60 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Gliese 251

Gliese 251 has a spectral type of K:.... This means the star is a orange to red star. The star has a B-V Colour Index of 1.58 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,828 Kelvin.

Gliese 251 has been calculated as 0.12 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 85,769.76.km.

Gliese 251 Apparent and Absolute Magnitudes

Gliese 251 has an apparent magnitude of 9.89 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 11.18 If you used the 2007 Parallax value, you would get an absolute magnitude of 11.15. 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 Gliese 251

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 181.32 which gave the calculated distance to Gliese 251 as 17.99 light years away from Earth or 5.52 parsecs. It would take a spaceship travelling at the speed of light, 17.99 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 179.01 which put Gliese 251 at a distance of 18.22 light years or 5.59 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.

Gliese 251 Facts

Alternative Names

Traditional NameGliese 251
Hipparcos Library I.D.33226
Henry Draper Designation265866

Visual Facts

Star Type star
Absolute Magnitude11.18 / 11.15
Apparent Magnitude9.89
Right Ascension (R.A.)06h 54m 49.47
Declination (Dec.)+33d16`08.9
1997 Distance from Earth181.32 Parallax (milliarcseconds)
 17.99 Light Years
 5.52 Parsecs
2007 Revised Distance from Earth179.01 Parallax (milliarcseconds)
 18.22 Light Years
 5.59 Parsecs
Proper Motion Dec.-398.40 ± 0.77 milliarcseconds/year
Proper Motion RA.-723.99 ± 1.60 milliarcseconds/year
B-V Index1.58
Spectral TypeK:...
Colour(K) Orange to Red

Estimated Facts

Radius (x the Sun)0.12
Calculated Effective Temperature3,828 Kelvin

Sources and Links

SIMBAD SourceLink

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