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DQ Cephei, HD199908, HIP103471

DQ Cephei is a blue to white pulsating luminous giant star that can be located in the constellation of Cepheus. The star can not be seen by the naked eye, you need a telescope to see it.

HIP103471 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD199908.

DQ Cephei has alternative name(s), DQ Cep.

Location of DQ 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 DQ Cephei, the location is 20h 57m 48.58 and +55d29`15.4 .

Proper Motion of DQ 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 20.79 ± 0.34 miliarcseconds/year towards the north and 26.02 ± 0.38 miliarcseconds/year east if we saw them in the horizon.

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

DQ Cephei has a spectral type of F2II. This means the star is a blue to white luminous giant star. The star is 7414.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24181.7503241600000000s. The star has a B-V Colour Index of 0.34 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,614 Kelvin.

DQ Cephei Radius has been calculated as being 4.02 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,795,421.33.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 4.47. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

DQ Cephei Apparent and Absolute Magnitudes

DQ Cephei has an apparent magnitude of 7.26 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 1.24 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.01. 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 DQ Cephei

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.25 which gave the calculated distance to DQ Cephei as 521.86 light years away from Earth or 160 parsecs. It would take a spaceship travelling at the speed of light, 521.86 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 5.63 which put DQ Cephei at a distance of 579.33 light years or 177.62 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 7,414.00 Parsecs or 24,181.75 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 DQ Cephei

The star is a pulsating Delta Scuti 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. DQ Cephei brightness ranges from a magnitude of 7.367 to a magnitude of 7.336 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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.

DQ Cephei Facts

Alternative Names

Traditional/Proper NameDQ Cephei
Short NameDQ Cep
Hipparcos Library I.D.103471
Bonner DurchmusterungBD+54 2452
Henry Draper Designation199908

Visual Facts

Star Typeluminous giant star
Absolute Magnitude1.24 / 1.01
Visual / Apparent Magnitude7.26
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)20h 57m 48.58
Declination (Dec.)+55d29`15.4
Galactic Latitude6.41 degrees
Galactic Longitude93.88 degrees
1997 Distance from Earth6.25 Parallax (milliarcseconds)
 521.86 Light Years
 160 Parsecs
2007 Revised Distance from Earth5.63 Parallax (milliarcseconds)
 579.33 Light Years
 177.62 Parsecs
Galacto-Centric Distance24,181.75 Light Years / 7,414.00 Parsecs
Proper Motion Dec.20.79 ± 0.34 milliarcseconds/year
Proper Motion RA.26.02 ± 0.38 milliarcseconds/year
B-V Index0.34
Radial Velocity-21.90 ± 999.00 km/s
Spectral TypeF2II
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti
Mean Variability Period in Days0.079
Variable Magnitude Range (Brighter - Dimmer)7.336 - 7.367

Estimated Facts

Calculated Effective Temperature6,614 Kelvin

Sources and Links

SIMBAD SourceLink

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