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Xi Herculis, 92 Herculis, HD163993, HIP87933

Xi Herculis is a orange to red pulsating giant star that can be located in the constellation of Hercules. Xi Herculis is the brightest star in Hercules 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 Herculis is the Bayer Classification for the star. HIP87933 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD163993.

Xi Herculis has alternative name(s), ksi Her.

Location of Xi Herculis

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 Xi Herculis, the location is 17h 57m 45.83 and +29d14`52.5 .

Proper Motion of Xi Herculis

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 -18.73 ± 0.11 miliarcseconds/year towards the north and 82.44 ± 0.15 miliarcseconds/year east if we saw them in the horizon.

Xi Herculis 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 96.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Xi Herculis

Xi Herculis has a spectral type of K0III. This means the star is a orange to red giant star. The star is 7378.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24064.3315203200000000s. The star has a B-V Colour Index of 0.93 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,989 Kelvin.

Xi Herculis Radius has been calculated as being 9.44 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 6,566,815.79.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 9.53. 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 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Xi Herculis Apparent and Absolute Magnitudes

Xi Herculis has an apparent magnitude of 3.70 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 0.61 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.59. 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 Xi Herculis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 24.12 which gave the calculated distance to Xi Herculis as 135.23 light years away from Earth or 41.46 parsecs. It would take a spaceship travelling at the speed of light, 135.23 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 23.84 which put Xi Herculis at a distance of 136.81 light years or 41.95 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 7,378.00 Parsecs or 24,064.33 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of Xi Herculis

The star is a pulsating Semi-Regular Star which are giants or supergiants of intermediate and late spectral variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. Xi Herculis brightness ranges from a magnitude of 3.876 to a magnitude of 3.847 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 120.8 days (variability).

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.

Xi Herculis Facts

Alternative Names

Flamsteed Name92 Herculis
Flamsteed Short Name92 Her
Short Nameksi Her
Bayer DesignationXi Herculis
Hipparcos Library I.D.87933
Bonner DurchmusterungBD+29 3156
Henry Draper Designation163993

Visual Facts

Star Typegiant star
Absolute Magnitude0.61 / 0.59
Visual / Apparent Magnitude3.70
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)17h 57m 45.83
Declination (Dec.)+29d14`52.5
Galactic Latitude23.77 degrees
Galactic Longitude54.91 degrees
1997 Distance from Earth24.12 Parallax (milliarcseconds)
 135.23 Light Years
 41.46 Parsecs
2007 Revised Distance from Earth23.84 Parallax (milliarcseconds)
 136.81 Light Years
 41.95 Parsecs
Galacto-Centric Distance24,064.33 Light Years / 7,378.00 Parsecs
Proper Motion Dec.-18.73 ± 0.11 milliarcseconds/year
Proper Motion RA.82.44 ± 0.15 milliarcseconds/year
B-V Index0.93
Radial Velocity-1.72 ± 0.12 km/s
Iron Abundance0.03 ± 9.99 Fe/H
Spectral TypeK0III
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemi-Regular Star which are giants or supergiants of intermediate and late spectral
Mean Variability Period in Days120.800
Variable Magnitude Range (Brighter - Dimmer)3.847 - 3.876

Estimated Facts

Luminosity (x the Sun)96.0000000
Calculated Effective Temperature4,989 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars


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