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51 G. Oph - HD151900 - HIP82405

51 G. Oph is a blue to white subgiant star that can be located in the constellation of Ophiuchus. HIP82405 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD151900. The Id of the star in the Gould Star Catalogue is 51. 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 51 G. Oph

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 51 G. Oph, the location is 16h 50m 22.25 and -02d39`15.3 .

Proper Motion of 51 G. Oph

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 -045.21 ± 000.28 towards the north and 004.03 ± 000.47 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 51 G. Oph

51 G. Oph has a spectral type of F1III-IV. This means the star is a blue to white subgiant star. The star has a B-V Colour Index of 0.4 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,728 Kelvin.

51 G. Oph has been calculated as 2.23 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,554,504.24.km.

51 G. Oph Apparent and Absolute Magnitudes

51 G. Oph has an apparent magnitude of 6.32 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 2.44 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.40. 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 51 G. Oph

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 16.71 which gave the calculated distance to 51 G. Oph as 195.19 light years away from Earth or 59.84 parsecs. It would take a spaceship travelling at the speed of light, 195.19 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 16.41 which put 51 G. Oph at a distance of 198.76 light years or 60.94 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.

51 G. Oph Facts

Alternative Names

Traditional Name51 G. Oph
Hipparcos Library I.D.82405
Bonner DurchmusterungBD-02 4259
Gould I.D.51
Henry Draper Designation151900

Visual Facts

Star Typesubgiant star
Absolute Magnitude2.44 / 2.40
Apparent Magnitude6.32
Right Ascension (R.A.)16h 50m 22.25
Declination (Dec.)-02d39`15.3
1997 Distance from Earth16.71 Parallax (milliarcseconds)
 195.19 Light Years
 59.84 Parsecs
2007 Revised Distance from Earth16.41 Parallax (milliarcseconds)
 198.76 Light Years
 60.94 Parsecs
Proper Motion Dec.-45.21 ± 0.28 milliarcseconds/year
Proper Motion RA.4.03 ± 0.47 milliarcseconds/year
B-V Index0.40
Spectral TypeF1III-IV
Colour(F) blue to white

Estimated Facts

Radius (x the Sun)2.23
Calculated Effective Temperature6,728 Kelvin

Sources and Links

SIMBAD SourceLink

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