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203 G. Cet, HD12642, HIP9622

203 G. Cet is a orange to red very luminous supergiant star that can be located in the constellation of Cetus. 203 G. Cet 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.

HIP9622 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD12642. The Id of the star in the Gould Star Catalogue is 203. 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.

Location of 203 G. Cet

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 203 G. Cet, the location is 02h 03m 40.48 and -04d 06` 12.1 .

Proper Motion of 203 G. Cet

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 -61.68 ± 0.17 miliarcseconds/year towards the north and 8.31 ± 0.29 miliarcseconds/year east if we saw them in the horizon.

203 G. Cet 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 20000.0000000 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 203 G. Cet

203 G. Cet has a spectral type of K5Iab:. This means the star is a orange to red supergiant star. The star is 7478.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24390.4948643200000000s. The star has a B-V Colour Index of 1.58 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,828 Kelvin.

203 G. Cet Radius has been calculated as being 32.13 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 22,359,022.23.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 26.61. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

203 G. Cet Apparent and Absolute Magnitudes

203 G. Cet has an apparent magnitude of 5.61 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 -0.90 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.49. 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 203 G. Cet

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.98 which gave the calculated distance to 203 G. Cet as 654.95 light years away from Earth or 200.80 parsecs. It would take a spaceship travelling at the speed of light, 654.95 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 6.02 which put 203 G. Cet at a distance of 541.80 light years or 166.11 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 7,478.00 Parsecs or 24,390.49 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*. 203 G. Cet brightness ranges from a magnitude of 5.752 to a magnitude of 5.714 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.

203 G. Cet Facts

Alternative Names

Traditional/Proper Name203 G. Cet
Hipparcos Library I.D.9622
Bonner DurchmusterungBD-04 324
Gould I.D.203
Henry Draper Designation12642

Visual Facts

Star Typesupergiant star
Absolute Magnitude-0.90 / -0.49
Visual / Apparent Magnitude5.61
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)02h 03m 40.48
Declination (Dec.)-04d 06` 12.1
Galactic Latitude-61.24 degrees
Galactic Longitude162.91 degrees
1997 Distance from Earth4.98 Parallax (milliarcseconds)
 654.95 Light Years
 200.80 Parsecs
2007 Revised Distance from Earth6.02 Parallax (milliarcseconds)
 541.80 Light Years
 166.11 Parsecs
Galacto-Centric Distance24,390.49 Light Years / 7,478.00 Parsecs
Proper Motion Dec.-61.68 ± 0.17 milliarcseconds/year
Proper Motion RA.8.31 ± 0.29 milliarcseconds/year
B-V Index1.58
Radial Velocity24.50 ± 2.90 km/s
Spectral TypeK5Iab:
Colour(K) Orange to Red

Variable Star Details

Mean Variability Period in Days0.027
Variable Magnitude Range (Brighter - Dimmer)5.714 - 5.752

Estimated Facts

Luminosity (x the Sun)20,000.0000000
Calculated Effective Temperature3,828 Kelvin

Sources and Links

SIMBAD SourceLink

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