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Psi2 Draconis, 34 Draconis, HD164613, HIP87728, HR6725

Psi2 Draconis is a blue to white giant star that can be located in the constellation of Draco. Psi2 Draconis is the brightest star in Draco 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.

Psi2 Draconis is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR6725. HIP87728 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD164613.

Location of Psi2 Draconis

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 Psi2 Draconis, the location is 17h 55m 11.14 and +72d 00` 18.5 .

Proper Motion of Psi2 Draconis

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 -2.48 ± 0.20 miliarcseconds/year towards the north and 8.33 ± 0.20 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Psi2 Draconis

Psi2 Draconis has a spectral type of F2.5II-III. This means the star is a blue to white giant star. The star is 7468.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24357.8785299200000000s. 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 7,016 Kelvin.

Psi2 Draconis Radius has been calculated as being 11.50 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 8,002,421.68.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 16.78. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Psi2 Draconis Apparent and Absolute Magnitudes

Psi2 Draconis has an apparent magnitude of 5.43 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 -1.30 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.12. 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 Psi2 Draconis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.51 which gave the calculated distance to Psi2 Draconis as 723.20 light years away from Earth or 221.73 parsecs. It would take a spaceship travelling at the speed of light, 723.20 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 3.09 which put Psi2 Draconis at a distance of 1055.54 light years or 323.62 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 7,468.00 Parsecs or 24,357.88 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

Psi2 Draconis Facts

Alternative Names

Flamsteed Name34 Draconis
Flamsteed Short Name34 Dra
Bayer DesignationPsi2 Draconis
Hipparcos Library I.D.87728
Yale Bright Star Catalogue (HR) Id6725
Bonner DurchmusterungBD+72 818
Henry Draper Designation164613

Visual Facts

Star Typegiant star
Absolute Magnitude-1.30 / -2.12
Visual / Apparent Magnitude5.43
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)17h 55m 11.14
Declination (Dec.)+72d 00` 18.5
Galactic Latitude30.03 degrees
Galactic Longitude102.68 degrees
1997 Distance from Earth4.51 Parallax (milliarcseconds)
 723.20 Light Years
 221.73 Parsecs
2007 Revised Distance from Earth3.09 Parallax (milliarcseconds)
 1055.54 Light Years
 323.62 Parsecs
Galacto-Centric Distance24,357.88 Light Years / 7,468.00 Parsecs
Proper Motion Dec.-2.48 ± 0.20 milliarcseconds/year
Proper Motion RA.8.33 ± 0.20 milliarcseconds/year
B-V Index0.34
Radial Velocity-2.00 ± 4.20 km/s
Spectral TypeF2.5II-III
Associated / Clustered StarsDsiban
Colour(F) blue to white

Estimated Facts

Calculated Effective Temperature7,016 Kelvin

Sources and Links

SIMBAD SourceLink

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