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X Centauri, HD102681, HIP57642

X Centauri is a red pulsating variable star that can be located in the constellation of Centaurus. The description is based on the spectral class. X Centauri is not part of the constellation but is within the borders of the constellation.

The star can not be seen by the naked eye, you need a telescope to see it.

X Centauri's Alternative Names

HIP57642 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD102681.

X Centauri has alternative name(s) :- , X Cen.

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

Location of X Centauri

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 X Centauri, the location is 11h 49m 11.81 and -41° 45` 27.3 .

Physical Properties (Colour, Temperature) of X Centauri

X Centauri has a spectral type of Md. This means the star is a red variable star. The star has a B-V Colour Index of 1.5 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,014 Kelvin.

X Centauri Radius has been calculated as being 45.06 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 31,350,982.68.km. If you need the diameter of the star, you just need to multiple the radius by 2. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

X Centauri Apparent and Absolute Magnitudes

X Centauri has an apparent magnitude of 10.04 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. Using the supplied Parallax value, you would get an absolute magnitude of -1.84 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 X Centauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.42 which gave the calculated distance to X Centauri as 7765.79 light years away from Earth or 2380.95 parsecs. It would take a spaceship travelling at the speed of light, 7765.79 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

Variable Type of X Centauri

The star is a pulsating Omicron Ceti 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. X Centauri brightness ranges from a magnitude of 11.106 to a magnitude of 7.509 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 312.0 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.

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X Centauri Facts

Visual Facts


Primary / Proper / Traditional NameX Centauri
Alternative NamesHD 102681, HIP 57642, X Cen
Spectral TypeMd
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
Colour red
GalaxyMilky Way
ConstellationCentaurus
Absolute Magnitude -1.84
Visual / Apparent Magnitude10.04
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)11h 49m 11.81
Declination (Dec.)-41° 45` 27.3
Galactic Latitude19.63 degrees
Galactic Longitude290.67 degrees
Distance from Earth0.42 Parallax (milliarcseconds)
 7765.79 Light Years
 2380.95 Parsecs
 491,102,768.38 Astronomical Units
B-V Index1.50
Radial Velocity38.00 ± 3.30 km/s

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Variable Star ClassPulsating
Variable Star TypeOmicron Ceti
Mean Variability Period in Days312.000
Variable Magnitude Range (Brighter - Dimmer)7.509 - 11.106

Estimated Facts


Calculated Effective Temperature4,014 Kelvin

Sources and Links


SIMBAD SourceLink

Related Stars


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