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VV Cephei - HD208816 - HIP108317

VV Cephei is a red eclipsing 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.

HIP108317 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD208816.

VV Cephei has alternative name(s), VV_Cep.

VV Cephei is one of the largest known stars in the milky way and is so big that if it was at the centre of this Solar System, it would encompass the Earth and extend to out past Jupiter.

Location of VV 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 VV Cephei, the location is 21h 56m 39.14 and +63d37`32.0 .

Proper Motion of VV 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 -2.56 ± 0.16 miliarcseconds/year towards the north and -0.25 ± 0.20 miliarcseconds/year east if we saw them in the horizon.

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

VV Cephei has a spectral type of M2 comp. This means the star is a red star. The star is 7600.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24788.4141440000000000s. The star has a B-V Colour Index of 1.54 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,926 Kelvin.

VV Cephei has been calculated as 1,050.00 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 730,590,000.00.km. The star's Iron Abundance is 0.01 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

VV Cephei Apparent and Absolute Magnitudes

VV Cephei has an apparent magnitude of 5.11 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 -6.93 If you used the 2007 Parallax value, you would get an absolute magnitude of -4.27. 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 VV Cephei

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.39 which gave the calculated distance to VV Cephei as 8363.16 light years away from Earth or 2564.10 parsecs. It would take a spaceship travelling at the speed of light, 8363.16 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 1.33 which put VV Cephei at a distance of 2452.36 light years or 751.88 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 7,600.00 Parsecs or 24,788.41 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 VV Cephei

The star is a eclipsing Beta Persei (Algol) and System with one or both giant or supergiant components (subtype) 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. VV Cephei brightness ranges from a magnitude of 5.000 to a magnitude of 5.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

VV Cephei Facts

Alternative Names

Traditional/Proper NameVV Cephei
Short NameVV Cep
Hipparcos Library I.D.108317
Bonner DurchmusterungBDD+62 2007
Henry Draper Designation208816

Visual Facts

Star Type star
Absolute Magnitude-6.93 / -4.27
Visual / Apparent Magnitude5.11
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)21h 56m 39.14
Declination (Dec.)+63d37`32.0
Galactic Latitude7.05 degrees
Galactic Longitude104.92 degrees
1997 Distance from Earth0.39 Parallax (milliarcseconds)
 8363.16 Light Years
 2564.10 Parsecs
2007 Revised Distance from Earth1.33 Parallax (milliarcseconds)
 2452.36 Light Years
 751.88 Parsecs
Galacto-Centric Distance24,788.41 Light Years / 7,600.00 Parsecs
Proper Motion Dec.-2.56 ± 0.16 milliarcseconds/year
Proper Motion RA.-0.25 ± 0.20 milliarcseconds/year
B-V Index1.54
Radial Velocity-13.56 ± 1.56 km/s
Iron Abundance0.01 ± 9.99 Fe/H
Spectral TypeM2 comp
Colour(M) Red

Variable Star Details

Variable Star ClassEclipsing
Variable Star TypeBeta Persei (Algol) and System with one or both giant or supergiant components (subtype)

Estimated Facts

Radius (x the Sun)1,050.00
Calculated Effective Temperature3,926 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
208816+62 2007.0A5.40000-5.000007.00000M1Red
B1950

Location of VV Cephei in Cepheus


VV Cephei Location in Cepheus

The map was generated using Night Vision, an awesome free application by Brian Simpson.


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