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BK Ceti, HD11522, HIP8778

BK Ceti is a blue to white pulsating main sequence dwarf star that can be located in the constellation of Cetus. BK Ceti is the brightest star in Cetus 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.

HIP8778 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD11522. The Id of the star in the Gould Star Catalogue is 188. 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.

BK Ceti has alternative name(s), BK Cet.

Location of BK Ceti

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 BK Ceti, the location is 01h 52m 52.09 and -16d55`44.8 .

Proper Motion of BK Ceti

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 -51.30 ± 0.54 miliarcseconds/year towards the north and 42.72 ± 0.65 miliarcseconds/year east if we saw them in the horizon.

BK Ceti 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 5.0000000 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 BK Ceti

BK Ceti has a spectral type of F0V. This means the star is a blue to white main sequence dwarf star. The star is 7429.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24230.6748257600000000s. The star has a B-V Colour Index of 0.26 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,428 Kelvin.

BK Ceti Radius has been calculated as being 3.99 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,777,388.78.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.71. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

BK Ceti Apparent and Absolute Magnitudes

BK Ceti has an apparent magnitude of 5.78 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 0.75 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.91. 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 BK Ceti

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 9.87 which gave the calculated distance to BK Ceti as 330.46 light years away from Earth or 101.32 parsecs. It would take a spaceship travelling at the speed of light, 330.46 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 10.62 which put BK Ceti at a distance of 307.12 light years or 94.16 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 7,429.00 Parsecs or 24,230.67 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 BK Ceti

The star is a pulsating Delta Scuti 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. BK Ceti brightness ranges from a magnitude of 5.877 to a magnitude of 5.837 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

BK Ceti Facts

Alternative Names

Traditional/Proper NameBK Ceti
Short NameBK Cet
Hipparcos Library I.D.8778
Bonner DurchmusterungBD-17 336
Gould I.D.188
Henry Draper Designation11522

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude0.75 / 0.91
Visual / Apparent Magnitude5.78
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)01h 52m 52.09
Declination (Dec.)-16d55`44.8
Galactic Latitude-72.52 degrees
Galactic Longitude180.42 degrees
1997 Distance from Earth9.87 Parallax (milliarcseconds)
 330.46 Light Years
 101.32 Parsecs
2007 Revised Distance from Earth10.62 Parallax (milliarcseconds)
 307.12 Light Years
 94.16 Parsecs
Galacto-Centric Distance24,230.67 Light Years / 7,429.00 Parsecs
Proper Motion Dec.-51.30 ± 0.54 milliarcseconds/year
Proper Motion RA.42.72 ± 0.65 milliarcseconds/year
B-V Index0.26
Radial Velocity-4.30 ± 1.70 km/s
Spectral TypeF0V
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti
Mean Variability Period in Days0.032
Variable Magnitude Range (Brighter - Dimmer)5.837 - 5.877

Estimated Facts

Luminosity (x the Sun)5.0000000
Calculated Effective Temperature7,428 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars


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