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Xi1 Librae, 13 Librae, HD131530, HIP72934

Xi1 Librae is a white to yellow giant star that can be located in the constellation of Libra. Xi1 Librae is the brightest star in Libra 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.

Xi1 Librae is the Bayer Classification for the star. HIP72934 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD131530.

Location of Xi1 Librae

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 Xi1 Librae, the location is 14h 54m 22.91 and -11d53`54.0 .

Proper Motion of Xi1 Librae

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 -7.85 ± 0.19 miliarcseconds/year towards the north and -54.87 ± 0.35 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Xi1 Librae

Xi1 Librae has a spectral type of G7III. This means the star is a white to yellow giant star. The star is 7325.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23891.4649480000000000s. The star has a B-V Colour Index of 0.98 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,888 Kelvin.

Xi1 Librae Radius has been calculated as being 10.15 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 7,065,129.62.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 9.39. 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 0.03 with an error value of 0.06 Fe/H with the Sun has a value of 1 to put it into context.

Xi1 Librae Apparent and Absolute Magnitudes

Xi1 Librae has an apparent magnitude of 5.78 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 0.54 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.71. 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 Xi1 Librae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 8.94 which gave the calculated distance to Xi1 Librae as 364.84 light years away from Earth or 111.86 parsecs. It would take a spaceship travelling at the speed of light, 364.84 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 9.68 which put Xi1 Librae at a distance of 336.95 light years or 103.31 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 7,325.00 Parsecs or 23,891.46 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.

Xi1 Librae Facts

Alternative Names

Flamsteed Name13 Librae
Flamsteed Short Name13 Lib
Bayer DesignationXi1 Librae
Hipparcos Library I.D.72934
Bonner DurchmusterungBD-11 3827
Henry Draper Designation131530

Visual Facts

Star Typegiant star
Absolute Magnitude0.54 / 0.71
Visual / Apparent Magnitude5.78
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)14h 54m 22.91
Declination (Dec.)-11d53`54.0
Galactic Latitude40.88 degrees
Galactic Longitude344.34 degrees
1997 Distance from Earth8.94 Parallax (milliarcseconds)
 364.84 Light Years
 111.86 Parsecs
2007 Revised Distance from Earth9.68 Parallax (milliarcseconds)
 336.95 Light Years
 103.31 Parsecs
Galacto-Centric Distance23,891.46 Light Years / 7,325.00 Parsecs
Proper Motion Dec.-7.85 ± 0.19 milliarcseconds/year
Proper Motion RA.-54.87 ± 0.35 milliarcseconds/year
B-V Index0.98
Radial Velocity-23.80 ± 2.90 km/s
Iron Abundance0.03 ± 0.06 Fe/H
Spectral TypeG7III
Colour(G) White to Yellow

Estimated Facts

Calculated Effective Temperature4,888 Kelvin

Sources and Links

SIMBAD SourceLink

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