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Zeta Coronae Australis, HD176638, HIP93542, HR7188

Zeta Coronae Australis is a blue main sequence dwarf star 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.

Zeta Coronae Australis's Alternative Names

Zeta Coronae Australis (Zet Cra) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR7188. HIP93542 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD176638.

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

Location of Zeta 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 Zeta Coronae Australis, the location is 19h 03m 06.83 and -42° 05` 42.0 .

Proper Motion of Zeta 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 -46.43 ± 0.16 miliarcseconds/year towards the north and 56.41 ± 0.28 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 -13.00000 km/s with an error of about 4.20 km/s .

Zeta Coronae Australis Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 48.00 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature) of Zeta Coronae Australis

Zeta Coronae Australis has a spectral type of A0Vn. This means the star is a blue main sequence dwarf star. The star is 7,345.00 Parsecs from the Galactic Centre or terms of Light Years is 23,956.70 s. The star has a B-V Colour Index of -0.02 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,839 Kelvin.

Zeta Coronae Australis Radius has been calculated as being 2.04 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,417,347.00.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 2.14. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Zeta Coronae Australis Apparent and Absolute Magnitudes

Zeta Coronae Australis has an apparent magnitude of 4.74 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 0.99 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.88. 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 Zeta Coronae Australis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 17.75 which gave the calculated distance to Zeta Coronae Australis as 183.75 light years away from Earth or 56.34 parsecs. It would take a spaceship travelling at the speed of light, 183.75 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 16.89 which put Zeta Coronae Australis at a distance of 193.11 light years or 59.21 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 7,345.00 Parsecs or 23,956.70 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.

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Zeta Coronae Australis Facts

Visual Facts


Primary / Proper / Traditional NameZeta Coronae Australis
Alternative NamesZet Cra, HD 176638, HIP 93542, HR 7188
Spectral TypeA0Vn
Multiple Star SystemNo / Unknown
Star Type main sequence Dwarf Star
Colour blue
GalaxyMilky Way
ConstellationCorona Australis
Absolute Magnitude0.99 / 0.88
Visual / Apparent Magnitude4.74
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)19h 03m 06.83
Declination (Dec.)-42° 05` 42.0
Galactic Latitude-19.83 degrees
Galactic Longitude354.91 degrees
1997 Distance from Earth17.75 Parallax (milliarcseconds)
 183.75 Light Years
 56.34 Parsecs
2007 Distance from Earth16.89 Parallax (milliarcseconds)
 193.11 Light Years
 59.21 Parsecs
Galacto-Centric Distance23,956.70 Light Years / 7,345.00 Parsecs
Proper Motion Dec.-46.43 ± 0.16 milliarcseconds/year
Proper Motion RA.56.41 ± 0.28 milliarcseconds/year
B-V Index-0.02
Radial Velocity-13.00 ± 4.20 km/s
Eccentricity0.09
Semi-Major Axis7976.00
Stellar Luminosity (Lsun)48.00

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Estimated Facts


Calculated Effective Temperature9,839 Kelvin

Sources and Links


SIMBAD SourceLink

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