Universe Guide

12 Ophiuchi - HD149661 - HIP81300

12 Ophiuchi is an orange to red main sequence dwarf star that can be located in the constellation of Ophiuchus. HIP is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD. The Id of the star in the Gould Star Catalogue is . 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.

Location of 12 Ophiuchi

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 .

Physical Properties/View of 12 Ophiuchi

12 Ophiuchi has a spectral type of K2V. This means the star is (K) orange to red coloured (V) main sequence (dwarf star). 12 Ophiuchi lies at a distance of 31.89 light years away from our Sun and our planet Earth or to put it another way, 9.50 parsecs away from the Sun.

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. 12 Ophiuchi has an absolute magnitude of 5.82 which is the apparent magnitude of an object if it were 32.6 light years away or 10 parsecs from Earth. 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.

The star's effective temperature is 5,277 Kelvin which is cooler than our own Sun's effective Temperature which is 5,777 Kelvin

12 Ophiuchi Radius has been calculated as being 0.82 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 570,556.00. km. The star's solar mass is 1.00 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

Source of Information

The source of the information came 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.

12 Ophiuchi Facts


Traditional Name12 Ophiuchi
Alternative Name(s)12 Ophiuchi
Hipparcos Library I.D.81300
Gould I.D.27
Henry Draper Designation149661
Celestial TypeStar
Absolute Magnitude5.82
Apparent Magnitude5.77
Right Ascension (R.A.)16h 36m 21.18
Declination (Dec.)-02 d 19 ` 25.8
Distance from the Sun / Earth31.89 Light Years
Spectral TypeK2V
Colour (K) orange to red
Star Type (IV) subgiant.
Variable Star ClassConstant, non-variable
Radius (x the Sun)0.82
Calculated Temperature Range3,700.00 - 5,200.00
Mass Compared to the Sun1.00


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