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DT Cygni, HD201078, HIP104185, HR8084

DT Cygni is a blue to white pulsating star that can be located in the constellation of Cygnus. 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 HR8084. HIP104185 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD201078.

DT Cygni has alternative name(s), DT Cyg.

Location of DT 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 DT Cygni, the location is 21h 06m 30.24 and +31d 11` 04.8 .

Proper Motion of DT 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 -5.02 ± 0.22 miliarcseconds/year towards the north and 4.25 ± 0.33 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 us is -1.30000 km/s with an error of about 0.40 km/s .

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

DT Cygni has a spectral type of F7.5Ib-IIv. This means the star is a blue to white star. The star is 7302.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23816.4473788800000000s. The star has a B-V Colour Index of 0.55 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,992 Kelvin.

DT Cygni Radius has been calculated as being 35.30 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 24,562,590.30.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 31.46. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is 0.13 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

DT Cygni Apparent and Absolute Magnitudes

DT Cygni has an apparent magnitude of 5.77 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 -3.05 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.80. 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 DT Cygni

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.72 which gave the calculated distance to DT Cygni as 1896.30 light years away from Earth or 581.40 parsecs. It would take a spaceship travelling at the speed of light, 1896.30 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 1.93 which put DT Cygni at a distance of 1689.97 light years or 518.13 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 7,302.00 Parsecs or 23,816.45 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 DT Cygni

The star is a pulsating Delta Cepheid 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. DT Cygni brightness ranges from a magnitude of 6.036 to a magnitude of 5.744 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 2.5 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.

DT Cygni Facts

Alternative Names

Traditional/Proper NameDT Cygni
Short NameDT Cyg
Hipparcos Library I.D.104185
Yale Bright Star Catalogue (HR) Id8084
Bonner DurchmusterungBD+30 4318
Henry Draper Designation201078

Visual Facts

Star Type star
Absolute Magnitude-3.05 / -2.80
Visual / Apparent Magnitude5.77
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)21h 06m 30.24
Declination (Dec.)+31d 11` 04.8
Galactic Latitude-10.78 degrees
Galactic Longitude76.55 degrees
1997 Distance from Earth1.72 Parallax (milliarcseconds)
 1896.30 Light Years
 581.40 Parsecs
2007 Revised Distance from Earth1.93 Parallax (milliarcseconds)
 1689.97 Light Years
 518.13 Parsecs
Galacto-Centric Distance23,816.45 Light Years / 7,302.00 Parsecs
Proper Motion Dec.-5.02 ± 0.22 milliarcseconds/year
Proper Motion RA.4.25 ± 0.33 milliarcseconds/year
B-V Index0.55
Radial Velocity-1.30 ± 0.40 km/s
Iron Abundance0.13 ± 9.99 Fe/H
Spectral TypeF7.5Ib-IIv
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Cepheid
Mean Variability Period in Days2.499
Variable Magnitude Range (Brighter - Dimmer)5.744 - 6.036

Estimated Facts

Calculated Effective Temperature5,992 Kelvin

Sources and Links

SIMBAD SourceLink

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