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Asellus Tertius (Kappa Bootis B) - HD124674 - HIP69481

Asellus Tertius (Kappa Bootis B) is a blue to white main sequence dwarf star that can be located in the constellation of Bootes. The star can not be seen by the naked eye, you need a telescope to see it.

Kappa Bootis B is the Bayer Classification for the star. HIP69481 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD124674.

Asellus Tertius has alternative name(s), 17 Bootis , 17 Boo. Asellus Tertius is a multiple star system with 2 stars orbiting in its solar system.

Location of Asellus Tertius

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 Asellus Tertius, the location is 14h 13m 27.75 and +51d47`16.4 .

Proper Motion of Asellus Tertius

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 -9.91 ± 0.78 miliarcseconds/year towards the north and 61.20 ± 0.95 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Asellus Tertius

Asellus Tertius has a spectral type of F1V. This means the star is a blue to white main sequence dwarf star. The star is 7403.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24145.8723563200000000s. The star has a B-V Colour Index of 0.39 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,775 Kelvin.

Asellus Tertius Radius has been calculated as being 1.93 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,341,350.97.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.49. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -0.11 with an error value of 0.08 Fe/H with the Sun has a value of 1 to put it into context.

Asellus Tertius Apparent and Absolute Magnitudes

Asellus Tertius has an apparent magnitude of 6.62 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 2.73 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.29. 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 Asellus Tertius

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 16.66 which gave the calculated distance to Asellus Tertius as 195.78 light years away from Earth or 60.02 parsecs. It would take a spaceship travelling at the speed of light, 195.78 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 21.53 which put Asellus Tertius at a distance of 151.49 light years or 46.45 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.

The star's Galacto-Centric Distance is 7,403.00 Parsecs or 24,145.87 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

Asellus Tertius Facts

Alternative Names

Traditional/Proper NameAsellus Tertius
Short Name17 Boo
Bayer DesignationKappa Bootis B
Alternative Name(s)17 Bootis
Hipparcos Library I.D.69481
Henry Draper Designation124674

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude2.73 / 3.29
Visual / Apparent Magnitude6.62
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)14h 13m 27.75
Declination (Dec.)+51d47`16.4
Galactic Latitude60.92 degrees
Galactic Longitude96.46 degrees
1997 Distance from Earth16.66 Parallax (milliarcseconds)
 195.78 Light Years
 60.02 Parsecs
2007 Revised Distance from Earth21.53 Parallax (milliarcseconds)
 151.49 Light Years
 46.45 Parsecs
Galacto-Centric Distance24,145.87 Light Years / 7,403.00 Parsecs
Proper Motion Dec.-9.91 ± 0.78 milliarcseconds/year
Proper Motion RA.61.20 ± 0.95 milliarcseconds/year
B-V Index0.39
Radial Velocity-21.50 ± 7.40 km/s
Iron Abundance-0.11 ± 0.08 Fe/H
Spectral TypeF1V
Colour(F) blue to white
Stars in Solar System2

Estimated Facts

Calculated Effective Temperature6,775 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Asellus Tertius in Bootes


Asellus Tertius (Kappa Bootis B) Location in Bootes

The map was generated using Night Vision, an awesome free application by Brian Simpson.


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