Universe Guide


Tabby's Star

Tabby's Star is a blue to white main sequence dwarf star that can be located in the constellation of Cygnus. Tabby's Star has alternative name(s), KIC 8462852, WTF Star , .

Being called Tabby`s star is alot easier to say and pronounce than its other more official name, KIC 8462852. It gets its name from the lead author of the intial study of the star, Tabetha S. Boyajian, a American female astronomer. It was a star that was picked up as part of kepler space telescope mission.

Its variability and periods of darkness has interested astronomers from around the world. The variability is irregular which has only been noticed in a very small number of other stars. It has led some people to speculate about extra-terrestrial/alien motives about the stars irregularity. Some have speculated it might be a Dyson Sphere such is the irregularity of the light. Its not the only one of its type but it is definately the easiest to say. Another star of its type is EPIC 204278916 which is not on this site.

A Super-Earth or indeed a Jupiter would not be able to explain the dip in brightness that occurs infrequently. A Jupiter would only be able to hide approximately 1% nothing on the scale that has been seen. Other possible reasons for the dip is large asteroid fields or even a brown dwarf on a highly elliptical orbit. A brown dwarf would surely be picked up by its radiation heat signature?

W.T.F. Star isn`t offensive term to many you might assume, its a play on the term. The F stands for Flux not ..... Flux being the amount of power that is radiated through a given area in the form of photons or other elementary particles, typically measured in W/m2. It is most useful when trying to determine the magnitude and spectral type of a star in astronomy.Ref: Wiki

Dyson Sphere Theory

Named after Freeman Dyson, a British astronomer, the theory is that an advanced alien race or humans in the far future have become so advanced that they have technology that has fully encompassed a star to gain power from it. Freeman wasn`t the first person to come up with an idea but he popularised the theory. The theory was created by Olaf Stapledon in a story called Star Maker in 1937. Ref: Wiki

Location of Tabby's Star

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 Tabby's Star, the location is 20h 06m 15.457 and +44d 27` 24.61 .

Proper Motion of Tabby's Star

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 -10.50 ± 2.40 miliarcseconds/year towards the north and -9.90 ± 2.60 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Mass, Radius) of Tabby's Star

Tabby's Star has a spectral type of F3V. This means the star is a blue to white main sequence dwarf star. The star has a B-V Colour Index of 0.577 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,979 Kelvin.

Tabby's Star has been calculated as 1.55 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,081,668.06.km. The star's solar mass is 1.43 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is 0.000000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

Tabby's Star Apparent and Absolute Magnitudes

Tabby's Star has an apparent magnitude of 11.71 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 3.74 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 Tabby's Star

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.56 which gave the calculated distance to Tabby's Star as 1276.57 light years away from Earth or 391.39 parsecs. It would take a spaceship travelling at the speed of light, 1276.57 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

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.

Tabby's Star Facts

Alternative Names

Traditional/Proper NameTabby's Star
Alternative Name(s)KIC 8462852, WTF Star

Visual Facts

Star Typemain sequence dwarf star
Apparent Magnitude11.71
Right Ascension (R.A.) 20h 06m 15.457
Declination (Dec.)+44d 27` 24.61
1997 Distance from Earth2.56 Parallax (milliarcseconds)
 1276.57 Light Years
 391.39 Parsecs
Proper Motion Dec.-10.50 ± 2.40 milliarcseconds/year
Proper Motion RA.-9.90 ± 2.60 milliarcseconds/year
B-V Index0.58
Spectral TypeF3V
Colour(F) blue to white

Estimated Facts

Radius (x the Sun)1.55
Calculated Effective Temperature5,979 Kelvin
Mass Compared to the Sun1.43

Sources and Links

SIMBAD SourceLink

Related Stars

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