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Ceginus (Phi Bootes) - HD139641 - HIP76534

Ceginus (Phi Bootes) is a white to yellow subgiant star that can be located in the constellation of Bootes. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Phi Bootes is the Bayer Classification for the star. HIP76534 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD139641.

Ceginus has alternative name(s), 54 Bootis , 54 Boo.

Location of Ceginus

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 Ceginus, the location is 15h 37m 49.55 and +40d21`11.8 .

Proper Motion of Ceginus

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 60.09 ± 0.20 miliarcseconds/year towards the north and 61.23 ± 0.24 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Ceginus

Ceginus has a spectral type of G8III-IV. This means the star is a white to yellow subgiant star. The star is 7387.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24093.6862212800000000s. The star has a B-V Colour Index of 0.88 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,096 Kelvin.

Ceginus Radius has been calculated as being 5.33 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,706,053.74.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 5.55. 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 -0.50 with an error value of 0.04 Fe/H with the Sun has a value of 1 to put it into context.

Ceginus Apparent and Absolute Magnitudes

Ceginus has an apparent magnitude of 5.25 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 1.76 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.67. 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 Ceginus

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 20.00 which gave the calculated distance to Ceginus as 163.08 light years away from Earth or 50 parsecs. It would take a spaceship travelling at the speed of light, 163.08 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 19.22 which put Ceginus at a distance of 169.70 light years or 52.03 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 7,387.00 Parsecs or 24,093.69 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.

Ceginus Facts

Alternative Names

Traditional/Proper NameCeginus
Short Name54 Boo
Bayer DesignationPhi Bootes
Alternative Name(s)54 Bootis
Hipparcos Library I.D.76534
Bonner DurchmusterungBDD+40 2907
Henry Draper Designation139641

Visual Facts

Star Typesubgiant star
Absolute Magnitude1.76 / 1.67
Visual / Apparent Magnitude5.25
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)15h 37m 49.55
Declination (Dec.)+40d21`11.8
Galactic Latitude53.36 degrees
Galactic Longitude64.95 degrees
1997 Distance from Earth20.00 Parallax (milliarcseconds)
 163.08 Light Years
 50 Parsecs
2007 Revised Distance from Earth19.22 Parallax (milliarcseconds)
 169.70 Light Years
 52.03 Parsecs
Galacto-Centric Distance24,093.69 Light Years / 7,387.00 Parsecs
Proper Motion Dec.60.09 ± 0.20 milliarcseconds/year
Proper Motion RA.61.23 ± 0.24 milliarcseconds/year
B-V Index0.88
Radial Velocity-10.00 ± 0.30 km/s
Iron Abundance-0.50 ± 0.04 Fe/H
Spectral TypeG8III-IV
Colour(G) White to Yellow

Estimated Facts

Calculated Effective Temperature5,096 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Ceginus in Bootes


Ceginus (Phi Bootes) Location in Bootes

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


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