R Coronae Australis is a blue luminous giant star that can be located in the constellation of CoronaAustralis. R Coronae Australis is the brightest star in Corona Australis based on the Hipparcos 2007 apparent magnitude. The star can not be seen by the naked eye, you need a telescope to see it.
HIP93449 is the reference name for the star in the Hipparcos Star Catalogue.
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 R Coronae Australis, the location is 19h 01m 53.68 and -36d57`08.1 .
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 20.57 ± 15.79 miliarcseconds/year towards the north and -28.30 ± 27.95 miliarcseconds/year east if we saw them in the horizon.
R Coronae Australis has a spectral type of A5IIevar. This means the star is a blue luminous giant star. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.
R Coronae Australis has an apparent magnitude of 11.57 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 12.00 If you used the 2007 Parallax value, you would get an absolute magnitude of 9.63. 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 121.75 which gave the calculated distance to R Coronae Australis as 26.79 light years away from Earth or 8.21 parsecs. It would take a spaceship travelling at the speed of light, 26.79 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 40.93 which put R Coronae Australis at a distance of 79.69 light years or 24.43 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.
|Traditional/Proper Name||R Coronae Australis|
|Hipparcos Library I.D.||93449|
|Star Type||luminous giant star|
|Absolute Magnitude||12.00 / 9.63|
|Visual / Apparent Magnitude||11.57|
|Naked Eye Visible||Requires a 4.5 - 6 Inch Telescope - Magnitudes|
|Right Ascension (R.A.)||19h 01m 53.68|
|Galactic Latitude||-17.85 degrees|
|Galactic Longitude||359.93 degrees|
|1997 Distance from Earth||121.75 Parallax (milliarcseconds)|
|26.79 Light Years|
|2007 Revised Distance from Earth||40.93 Parallax (milliarcseconds)|
|79.69 Light Years|
|Proper Motion Dec.||20.57 ± 15.79 milliarcseconds/year|
|Proper Motion RA.||-28.30 ± 27.95 milliarcseconds/year|
|Radial Velocity||-36.00 ± 4.90 km/s|