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17 Comae Berenices B, 17 Comae Berenices, HD108662, HIP60904

17 Comae Berenices B is a blue rotating star that can be located in the constellation of ComaBerenices. 17 Comae Berenices B is the brightest star in Coma Berenices 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.

HIP60904 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD108662.

17 Comae Berenices B has alternative name(s), AI Com.

Location of 17 Comae Berenices B

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 17 Comae Berenices B, the location is 12h 28m 54.72 and +25d54`46.4 .

Proper Motion of 17 Comae Berenices B

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 -15.46 ± 0.17 miliarcseconds/year towards the north and -21.94 ± 0.25 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 17 Comae Berenices B

17 Comae Berenices B has a spectral type of A0p. This means the star is a blue star. The star is 7405.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24152.3956232000000000s. The star has a B-V Colour Index of -0.05 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 11,775 Kelvin.

17 Comae Berenices B Radius has been calculated as being 1.63 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,130,990.94.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.43. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

The star has a companion star which is in orbit close by, it has at least the following companions in close orbit, .

17 Comae Berenices B Apparent and Absolute Magnitudes

17 Comae Berenices B has an apparent magnitude of 5.29 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 0.70 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.98. 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 17 Comae Berenices B

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 12.06 which gave the calculated distance to 17 Comae Berenices B as 270.45 light years away from Earth or 82.92 parsecs. It would take a spaceship travelling at the speed of light, 270.45 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 13.72 which put 17 Comae Berenices B at a distance of 237.73 light years or 72.89 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 7,405.00 Parsecs or 24,152.40 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 17 Comae Berenices B

The star is a rotating Alpha2 Canum Venaticorum 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. 17 Comae Berenices B brightness ranges from a magnitude of 5.253 to a magnitude of 5.231 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 5.1 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.

17 Comae Berenices B Facts

Alternative Names

Traditional/Proper Name17 Comae Berenices B
Flamsteed Name17 Comae Berenices
Flamsteed Short Name17 Com
Short NameAI Com
Hipparcos Library I.D.60904
Bonner DurchmusterungBD+26 2354
Henry Draper Designation108662

Visual Facts

Star Type star
Absolute Magnitude0.70 / 0.98
Visual / Apparent Magnitude5.29
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)12h 28m 54.72
Declination (Dec.)+25d54`46.4
Galactic Latitude84.82 degrees
Galactic Longitude225.22 degrees
1997 Distance from Earth12.06 Parallax (milliarcseconds)
 270.45 Light Years
 82.92 Parsecs
2007 Revised Distance from Earth13.72 Parallax (milliarcseconds)
 237.73 Light Years
 72.89 Parsecs
Galacto-Centric Distance24,152.40 Light Years / 7,405.00 Parsecs
Proper Motion Dec.-15.46 ± 0.17 milliarcseconds/year
Proper Motion RA.-21.94 ± 0.25 milliarcseconds/year
B-V Index-0.05
Radial Velocity-1.40 ± 0.50 km/s
Spectral TypeA0p
Colour(A) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeAlpha2 Canum Venaticorum
Mean Variability Period in Days5.079
Variable Magnitude Range (Brighter - Dimmer)5.231 - 5.253

Estimated Facts

Calculated Effective Temperature11,775 Kelvin

Sources and Links

SIMBAD SourceLink

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