12 Ophiuchi is an orange to red main sequence dwarf star that can be located in the constellation of Ophiuchus. HIP81300 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD149661. The Id of the star in the Gould Star Catalogue is 27. 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. 12 Ophiuchi has alternative name(s), 12 Ophiuchi , 12 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 from celestial equator. The Declination is how up or down compared to the celestial equator and is expressed in degrees. For 12 Ophiuchi, the location is 16h 36m 21.18 and -02 d 19 ` 25.8 .
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 -310.00 ± 000.00 towards the north and 456.00 ± 000.00 east if we saw them in the horizon.
12 Ophiuchi has a spectral type of K2V. This means the star is an orange to red coloured main sequence dwarf star. The star has a B-V Colour Index of 0.82 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,236 Kelvin.
12 Ophiuchi has been calculated as 0.78 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 543,665.17.km.
12 Ophiuchi has an apparent magnitude of 5.77 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 5.81 If you used the 2007 Parallax value, you would get an absolute magnitude of 5.83. 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.
Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 102.00 which gave the calculated distance to 12 Ophiuchi as 31.98 light years away from us or 9.80 parsecs. In 2007, Hipparcos data was revised with a new parallax of 103.00 which put 12 Ophiuchi at a distance of 31.67 light years or 9.71 parsecs.
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.
|Traditional Name||12 Ophiuchi|
|Short Name||12 Oph|
|Alternative Name(s)||12 Ophiuchi|
|Hipparcos Library I.D.||81300|
|Henry Draper Designation||149661|
|Absolute Magnitude||5.81 / 5.83|
|Right Ascension (R.A.)||16h 36m 21.18|
|Declination (Dec.)||-02 d 19 ` 25.8|
|1997 Distance||102.00 Parallax (milliarcseconds)|
|31.98 Light Years|
|2007 Distance||103.00 Parallax (milliarcseconds)|
|31.67 Light Years|
|Proper Motion Dec.||-310.00 ± 0.00 milliarcseconds/year|
|Proper Motion RA.||456.00 ± 0.00 milliarcseconds/year|
|Colour||(K) Orange to Red|
|Star Type||main sequence dwarf star|
|Radius (x the Sun)||0.78|
|Calculated Effective Temperature||5,236 Kelvin|