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WASP-18, HD10069, HIP7562

WASP-18 is a blue to white star that can be located in the constellation of Phoenix. The star can not be seen by the naked eye, you need a telescope to see it.

HIP7562 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD10069.

Location of WASP-18

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 WASP-18, the location is 01h 37m 25.01 and -45d 40` 40.6 .

Proper Motion of WASP-18

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 18.79 ± 0.95 miliarcseconds/year towards the north and 26.52 ± 1.07 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 2.78000 km/s with an error of about 0.20 km/s .

Physical Properties (Colour, Temperature, Radius) of WASP-18

WASP-18 has a spectral type of F6IV/V. This means the star is a blue to white star. The star is 7395.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24119.7792888000000000s. The star has a B-V Colour Index of 0.49 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,327 Kelvin.

WASP-18 Radius has been calculated as being 1.14 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 796,070.11.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.08. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

WASP-18 Apparent and Absolute Magnitudes

WASP-18 has an apparent magnitude of 9.28 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 4.16 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.29. 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 WASP-18

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 9.48 which gave the calculated distance to WASP-18 as 344.05 light years away from Earth or 105.49 parsecs. It would take a spaceship travelling at the speed of light, 344.05 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 10.06 which put WASP-18 at a distance of 324.22 light years or 99.40 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 7,395.00 Parsecs or 24,119.78 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.

WASP-18 Facts

Alternative Names

Traditional/Proper NameWASP-18
Hipparcos Library I.D.7562
Henry Draper Designation10069

Visual Facts

Star Type star
Absolute Magnitude4.16 / 4.29
Visual / Apparent Magnitude9.28
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)01h 37m 25.01
Declination (Dec.)-45d 40` 40.6
Galactic Latitude-69.32 degrees
Galactic Longitude279.71 degrees
1997 Distance from Earth9.48 Parallax (milliarcseconds)
 344.05 Light Years
 105.49 Parsecs
2007 Revised Distance from Earth10.06 Parallax (milliarcseconds)
 324.22 Light Years
 99.40 Parsecs
Galacto-Centric Distance24,119.78 Light Years / 7,395.00 Parsecs
Proper Motion Dec.18.79 ± 0.95 milliarcseconds/year
Proper Motion RA.26.52 ± 1.07 milliarcseconds/year
B-V Index0.49
Radial Velocity2.78 ± 0.20 km/s
Spectral TypeF6IV/V
Colour(F) blue to white

Estimated Facts

Calculated Effective Temperature6,327 Kelvin

Sources and Links

SIMBAD SourceLink

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