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68 Cygni, HD203064, HIP105186, HR8154

68 Cygni is a blue rotating star that can be located in the constellation of Cygnus. 68 Cygni is the brightest star in Cygnus based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

The Id of the star in the Yale Bright Star Catalogue is HR8154. HIP105186 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD203064.

68 Cygni has alternative name(s), V1809 Cyg.

Location of 68 Cygni

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 68 Cygni, the location is 21h 18m 27.18 and +43 d 56` 45.5 .

Proper Motion of 68 Cygni

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 -8.40 ± 0.17 miliarcseconds/year towards the north and 4.85 ± 0.23 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 68 Cygni

68 Cygni has a spectral type of O8. This means the star is a blue star. The star has a B-V Colour Index of -0.06 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,136 Kelvin. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

68 Cygni Apparent and Absolute Magnitudes

68 Cygni has an apparent magnitude of 5.04 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 If you used the 2007 Parallax value, you would get an absolute magnitude of -5.73. 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 68 Cygni

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.00 which gave the calculated distance to 68 Cygni as -1 light years away from Earth or -1 parsecs. It would take a spaceship travelling at the speed of light, -1 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 0.70 which put 68 Cygni at a distance of 4659.48 light years or 1428.57 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.

Variable Type of 68 Cygni

The star is a rotating Rotating ellipsoidal 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. 68 Cygni brightness ranges from a magnitude of 5.035 to a magnitude of 5.003 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 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.

68 Cygni Facts

Alternative Names

Traditional/Proper Name68 Cygni
Flamsteed Name68 Cygni
Flamsteed Short Name68 Cyg
Short NameV1809 Cyg
Hipparcos Library I.D.105186
Yale Bright Star Catalogue (HR) Id8154
Bonner DurchmusterungBD+43 3877
Henry Draper Designation203064

Visual Facts

Star Type star
Visual / Apparent Magnitude5.04
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)21h 18m 27.18
Declination (Dec.)+43 d 56` 45.5
Galactic Latitude-3.84 degrees
Galactic Longitude87.61 degrees
1997 Distance from Earth0.00 Parallax (milliarcseconds)
 -1 Light Years
 -1 Parsecs
2007 Revised Distance from Earth0.70 Parallax (milliarcseconds)
 4659.48 Light Years
 1428.57 Parsecs
Proper Motion Dec.-8.40 ± 0.17 milliarcseconds/year
Proper Motion RA.4.85 ± 0.23 milliarcseconds/year
B-V Index-0.06
Radial Velocity-30.00 ± 10.00 km/s
Spectral TypeO8
Colour(O) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeRotating ellipsoidal
Mean Variability Period in Days0.024
Variable Magnitude Range (Brighter - Dimmer)5.003 - 5.035

Estimated Facts

Calculated Effective Temperature12,136 Kelvin

Sources and Links

SIMBAD SourceLink

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