Graffias (Xi Scorpii) is a blue to white subgiant star that can be located in the constellation of Scorpius. Graffias is the brightest star in Scorpius based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
Xi Scorpii is the Bayer Classification for the star. HIP78727 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD144069.
The star Acrab which is in the same constellation is also known by some people as Graffias. Both this and the other star that is referred to as Graffias are in the same constellation. Graffias is a multiple star system which has at least five stars in the system in two groups. The first group, contains three stars with "A" which is a sub-giant meaning that it nearing the end of hydrogen burning phase and it is expanding to becoming a Red Giant at which point it will be nearing the end of its life.
The nearest companion star orbits at about the same distance our Sun is to Uranus. The second of the orbiting stars orbits at a distance of ten times that of the inner star. The second pairing of the stars orbits the first pairing at a distance of more 310 times the distances of the Sun to Uranus.1
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 Graffias, the location is 16h 04m 21.63 and -11 d 22 ` 24.8 .
Graffias has a spectral type of F6IV. This means the star is a blue to white subgiant star. The star has a B-V Colour Index of 0.46 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,456 Kelvin.
Graffias has an apparent magnitude of 4.16 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. 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 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.
|Bayer Designation||Xi Scorpii|
|Hipparcos Library I.D.||78727|
|Bonner Durchmusterung||BD-10 4237|
|Henry Draper Designation||144069|
|Star Type||subgiant star|
|Visual / Apparent Magnitude||4.16|
|Naked Eye Visible||Yes - Magnitudes|
|Right Ascension (R.A.)||16h 04m 21.63|
|Declination (Dec.)||-11 d 22 ` 24.8|
|Colour||(F) blue to white|
|Calculated Effective Temperature||6,456 Kelvin|
The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.
|Proper Motion mas/yr|
|H.D. Id||B.D. Id||Star Code||Magnitude||R.A.||Dec.||Spectrum||Colour||Year|
The map was generated using Night Vision, an awesome free application by Brian Simpson.