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Cebalrai (Beta Ophiuchi) - HD161096 - HIP86742 - HR6603

Cebalrai (Beta Ophiuchi) is a orange to red giant star that can be located in the constellation of Ophiuchus. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Beta Ophiuchi is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR6603. HIP86742 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD161096. The Id of the star in the Gould Star Catalogue is 168. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major.

Cebalrai has alternative name(s), Celbalrai,60 Ophiuchi , 60 Oph.

Location of Cebalrai

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 Cebalrai, the location is 17h 43m 28.38 and +04d34`00.9 .

Proper Motion of Cebalrai

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 159.34 ± 0.09 miliarcseconds/year towards the north and -41.45 ± 0.17 miliarcseconds/year east if we saw them in the horizon.

Cebalrai Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 70.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Cebalrai

Cebalrai has a spectral type of K2III. This means the star is a orange to red giant star. The star is 7379.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24067.5931537600000000s. The star has a B-V Colour Index of 1.16 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,558 Kelvin.

Cebalrai Radius has been calculated as being 10.55 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 7,342,293.27.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 10.55. 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 0.14 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Cebalrai Apparent and Absolute Magnitudes

Cebalrai has an apparent magnitude of 2.76 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 0.76 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.76. 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 Cebalrai

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 39.78 which gave the calculated distance to Cebalrai as 81.99 light years away from Earth or 25.14 parsecs. It would take a spaceship travelling at the speed of light, 81.99 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 39.85 which put Cebalrai at a distance of 81.85 light years or 25.09 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 7,379.00 Parsecs or 24,067.59 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.

Cebalrai Facts

Alternative Names

Traditional/Proper NameCebalrai
Short Name60 Oph
Bayer DesignationBeta Ophiuchi
Alternative Name(s)Celbalrai,60 Ophiuchi
Hipparcos Library I.D.86742
Yale Bright Star Catalogue (HR) Id6603
Bonner DurchmusterungBDD+04 3489
Gould I.D.168
Henry Draper Designation161096

Visual Facts

Star Typegiant star
Absolute Magnitude0.76 / 0.76
Visual / Apparent Magnitude2.76
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)17h 43m 28.38
Declination (Dec.)+04d34`00.9
Galactic Latitude17.19 degrees
Galactic Longitude29.21 degrees
1997 Distance from Earth39.78 Parallax (milliarcseconds)
 81.99 Light Years
 25.14 Parsecs
2007 Revised Distance from Earth39.85 Parallax (milliarcseconds)
 81.85 Light Years
 25.09 Parsecs
Galacto-Centric Distance24,067.59 Light Years / 7,379.00 Parsecs
Proper Motion Dec.159.34 ± 0.09 milliarcseconds/year
Proper Motion RA.-41.45 ± 0.17 milliarcseconds/year
B-V Index1.16
Radial Velocity-12.53 ± 0.01 km/s
Iron Abundance0.14 ± 9.99 Fe/H
Spectral TypeK2III
Colour(K) Orange to Red

Estimated Facts

Luminosity (x the Sun)70.0000000
Calculated Effective Temperature4,558 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Cebalrai in Ophiuchus


Cebalrai (Beta Ophiuchi) Location in Ophiuchus

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


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