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V444 Cephei - HD210071 - HIP109124

V444 Cephei is a blue eclipsing binary system giant star that can be located in the constellation of Cepheus. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP109124 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD210071.

V444 Cephei has alternative name(s), V444_Cep.

Location of V444 Cephei

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 V444 Cephei, the location is 22h 06m 13.55 and +56d20`36.2 .

Proper Motion of V444 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 2.44 ± 0.25 miliarcseconds/year towards the north and 17.00 ± 0.33 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of V444 Cephei

V444 Cephei has a spectral type of A0III. This means the star is a blue giant star. The star is 7442.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24273.0760604800000000s. The star has a B-V Colour Index of -0.09 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 11,375 Kelvin.

V444 Cephei Radius has been calculated as being 2.25 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,568,496.83.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.52. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V444 Cephei Apparent and Absolute Magnitudes

V444 Cephei has an apparent magnitude of 6.38 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 0.14 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.10. 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 V444 Cephei

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 5.66 which gave the calculated distance to V444 Cephei as 576.26 light years away from Earth or 176.68 parsecs. It would take a spaceship travelling at the speed of light, 576.26 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 5.06 which put V444 Cephei at a distance of 644.59 light years or 197.63 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 7,442.00 Parsecs or 24,273.08 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 V444 Cephei

The star is a eclipsing binary system Eclipsing 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. V444 Cephei brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.0 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.

V444 Cephei Facts

Alternative Names

Traditional/Proper NameV444 Cephei
Short NameV444 Cep
Hipparcos Library I.D.109124
Bonner DurchmusterungBDD+55 2679
Henry Draper Designation210071

Visual Facts

Star Typegiant star
Absolute Magnitude0.14 / -0.10
Visual / Apparent Magnitude6.38
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)22h 06m 13.55
Declination (Dec.)+56d20`36.2
Galactic Latitude0.52 degrees
Galactic Longitude101.47 degrees
1997 Distance from Earth5.66 Parallax (milliarcseconds)
 576.26 Light Years
 176.68 Parsecs
2007 Revised Distance from Earth5.06 Parallax (milliarcseconds)
 644.59 Light Years
 197.63 Parsecs
Galacto-Centric Distance24,273.08 Light Years / 7,442.00 Parsecs
Proper Motion Dec.2.44 ± 0.25 milliarcseconds/year
Proper Motion RA.17.00 ± 0.33 milliarcseconds/year
B-V Index-0.09
Radial Velocity-29.00 ± 3.90 km/s
Spectral TypeA0III
Colour(A) blue

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeEclipsing
Mean Variability Period in Days1.000

Estimated Facts

Calculated Effective Temperature11,375 Kelvin

Sources and Links

SIMBAD SourceLink

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