Universe Guide
HomeAliensConstellationsTelevision and Films ListFact ListGames ListWarcraftSearchTwitterFacebook

XZ Cephei, HIP111257

XZ Cephei is a blue main sequence dwarf star that can be located in the constellation of Cepheus. The description is based on the spectral class. The star can not be seen by the naked eye, you need a telescope to see it.

XZ Cephei's Alternative Names

HIP111257 is the reference name for the star in the Hipparcos Star Catalogue.

XZ Cephei has alternative name(s) :- , XZ Cep.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+66 1521.

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

Location of XZ Cephei

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 XZ Cephei, the location is 22h 32m 25.08 and +67° 09` 02.5 .

Radial Velocity and Proper Motion of XZ Cephei

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 -3.96 ± 0.54 miliarcseconds/year towards the north and -0.70 ± 0.63 miliarcseconds/year east if we saw them in the horizon.

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -3.00 km/s with an error of about 7.40 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties (Colour, Temperature) of XZ Cephei

XZ Cephei has a spectral type of O9.5V. This means the star is a blue main sequence dwarf star. The star has a B-V Colour Index of 0.68 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,625 Kelvin.

XZ Cephei Radius has been calculated as being 11.71 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 8,149,791.67.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 10.83. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

XZ Cephei Apparent and Absolute Magnitudes

XZ Cephei has an apparent magnitude of 8.42 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 -0.38 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.21. 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 XZ Cephei

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.74 which gave the calculated distance to XZ Cephei as 1874.50 light years away from Earth or 574.71 parsecs. It would take a spaceship travelling at the speed of light, 1874.50 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 1.88 which put XZ Cephei at a distance of 1734.91 light years or 531.91 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. XZ Cephei brightness ranges from a magnitude of 9.354 to a magnitude of 8.480 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 5.1 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.

Hide Explanations
Show GridLines

XZ Cephei Facts

Visual Facts


Primary / Proper / Traditional NameXZ Cephei
Alternative NamesHIP 111257, BD+66 1521, XZ Cep
Spectral TypeO9.5V
Multiple Star SystemNo / Unknown
Star Type main sequence Dwarf Star
Colour blue
GalaxyMilky Way
ConstellationCepheus
Absolute Magnitude-0.38 / -0.21
Visual / Apparent Magnitude8.42
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)22h 32m 25.08
Declination (Dec.)+67° 09` 02.5
Galactic Latitude7.83 degrees
Galactic Longitude110.02 degrees
1997 Distance from Earth1.74 Parallax (milliarcseconds)
 1874.50 Light Years
 574.71 Parsecs
2007 Distance from Earth1.88 Parallax (milliarcseconds)
 1734.91 Light Years
 531.91 Parsecs
Proper Motion Dec.-3.96 ± 0.54 milliarcseconds/year
Proper Motion RA.-0.70 ± 0.63 milliarcseconds/year
B-V Index0.68
Radial Velocity-3.00 ± 7.40 km/s

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Mean Variability Period in Days5.098
Variable Magnitude Range (Brighter - Dimmer)8.480 - 9.354

Estimated Facts


Calculated Effective Temperature5,625 Kelvin

Sources and Links


SIMBAD SourceLink

Related Stars


Add a Comment


Name:
Email: (Optional)
Comment: