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Kappa2 Coronae Australis, HD170868, HIP90968, HR6952

Kappa2 Coronae Australis is a blue multiple star system that can be located in the constellation of Corona Australis. The description is based on the spectral class. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Kappa2 Coronae Australis's Alternative Names

Kappa2 Coronae Australis (Kap02 Cra) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR6952. HIP90968 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD170868.

More details on star alternative names can be found at Star Names .

Location of Kappa2 Coronae Australis

The location of the star in the night sky 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 Kappa2 Coronae Australis, the location is 18h 33m 23.13 and -38° 43` 33.4 .

Proper Motion of Kappa2 Coronae Australis

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 -21.97 ± 1.30 miliarcseconds/year towards the north and 2.76 ± 2.10 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is -15.00000 km/s with an error of about 7.40 km/s .

Physical Properties (Colour, Temperature) of Kappa2 Coronae Australis

Kappa2 Coronae Australis has a spectral type of B9.5. This means the star is a blue multiple star system. The star has a B-V Colour Index of -0.06 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,136 Kelvin.

Kappa2 Coronae Australis Radius has been calculated as being 8.18 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 5,692,008.74.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 4.62. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Kappa2 Coronae Australis Apparent and Absolute Magnitudes

Kappa2 Coronae Australis has an apparent magnitude of 5.67 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 -2.94 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.70. 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 Kappa2 Coronae Australis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.90 which gave the calculated distance to Kappa2 Coronae Australis as 1716.65 light years away from Earth or 526.32 parsecs. It would take a spaceship travelling at the speed of light, 1716.65 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 3.35 which put Kappa2 Coronae Australis at a distance of 973.62 light years or 298.51 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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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Kappa2 Coronae Australis Facts

Visual Facts

Primary / Proper / Traditional NameKappa2 Coronae Australis
Alternative NamesKap02 Cra, HD 170868, HIP 90968, HR 6952
Spectral TypeB9.5
Multiple Star SystemYes
Star TypeMultiple Star System
Colour blue
GalaxyMilky Way
ConstellationCorona Australis
Absolute Magnitude-2.94 / -1.70
Visual / Apparent Magnitude5.67
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)18h 33m 23.13
Declination (Dec.)-38° 43` 33.4
Galactic Latitude-13.33 degrees
Galactic Longitude355.99 degrees
1997 Distance from Earth1.90 Parallax (milliarcseconds)
 1716.65 Light Years
 526.32 Parsecs
2007 Distance from Earth3.35 Parallax (milliarcseconds)
 973.62 Light Years
 298.51 Parsecs
Proper Motion Dec.-21.97 ± 1.30 milliarcseconds/year
Proper Motion RA.2.76 ± 2.10 milliarcseconds/year
B-V Index-0.06
Radial Velocity-15.00 ± 7.40 km/s
Associated / Clustered StarsKappa1 Coronae Australis

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Facts

Calculated Effective Temperature12,136 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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