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Sheliak (Beta Lyrae) - HD174638 - HIP92420 - HR7106

Sheliak (Beta Lyrae) is a blue eclipsing binary system main sequence dwarf star that can be located in the constellation of Lyra. Beta Lyrae is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR7106. HIP92420 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD174638. Sheliak has alternative name(s), 10 Lyrae , bet_Lyr, 10 Lyr.

Location of Sheliak

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 Sheliak, the location is 18h 50m 04.79 and +33d21`45.6 .

Proper Motion of Sheliak

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 -003.53 ± 000.15 towards the north and 001.90 ± 000.17 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Sheliak

Sheliak has a spectral type of A8:V comp SB. This means the star is a blue main sequence dwarf star. The star has a B-V Colour Index of 0 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,531 Kelvin.

Sheliak has been calculated as 18.31 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 12,739,331.15.km.

Sheliak Apparent and Absolute Magnitudes

Sheliak has an apparent magnitude of 3.52 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 -3.64 If you used the 2007 Parallax value, you would get an absolute magnitude of -3.83. 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 Sheliak

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.70 which gave the calculated distance to Sheliak as 881.52 light years away from Earth or 270.27 parsecs. It would take a spaceship travelling at the speed of light, 881.52 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 3.39 which put Sheliak at a distance of 962.13 light years or 294.99 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.

Variable Type of Sheliak

The star is a eclipsing binary system Beta Lyrae (Sheliak) 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. Sheliak brightness ranges from a magnitude of 4.000 to a magnitude of 3.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 13.0 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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Sheliak Facts

Alternative Names

Traditional NameSheliak
Short Namebet Lyr, 10 Lyr
Bayer DesignationBeta Lyrae
Alternative Name(s)10 Lyrae
Hipparcos Library I.D.92420
Yale Bright Star Catalogue (HR) Id7106
Bonner DurchmusterungBD+33 3223
Henry Draper Designation174638

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude-3.64 / -3.83
Apparent Magnitude3.52
Right Ascension (R.A.)18h 50m 04.79
Declination (Dec.)+33d21`45.6
1997 Distance from Earth3.70 Parallax (milliarcseconds)
 881.52 Light Years
 270.27 Parsecs
2007 Revised Distance from Earth3.39 Parallax (milliarcseconds)
 962.13 Light Years
 294.99 Parsecs
Proper Motion Dec.-3.53 ± 0.15 milliarcseconds/year
Proper Motion RA.1.90 ± 0.17 milliarcseconds/year
B-V Index0.00
Spectral TypeA8:V comp SB
Colour(A) blue

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeBeta Lyrae (Sheliak)
Mean Variability Period in Days13.000
Variable Magnitude Range (Brighter - Dimmer)3.000 - 4.000

Estimated Facts

Radius (x the Sun)18.31
Calculated Effective Temperature9,531 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
174638+33 3223.0A0.00000-2.00000B8Blue/White
174664+33 3224.0B8.60000-17.00000-4.00000B3Blue/White1835
C13.000001878
D14.300001898
+33 3222.0E9.90000-25.000003.000001879
+33 3225.0F9.90000-17.00000-9.000001879

Location of Sheliak in Lyra


Sheliak (Beta Lyrae) Location in Lyra

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


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