The planet WASP-13b is 1.37 times the radius of Jupiter, the largest planet in our Solar System. It is thus a gas giant vastly bigger than Earth.

WASP-13b is only half the mass of Jupiter, which means that WASP-13b is much less dense. Like many hot-Jupiter planets it has a bloated radius caused by it being hotter than Jupiter inside.

The star WASP-13 has a radius 1.5 times that of the Sun. Its mass and temperature, however, are very similar to the Sun. Its spectral type is G1, whereas the Sun is a G2 star. The fact that WASP-13’s radius is so much bigger means that it is in the process of evolving into a Red Giant star.

WASP-13b orbits at a distance of 8.05 million km, taking 4.35 days to go round its orbit.

WASP-13 lies in the constellation of Lynx. Its coordinates are right ascension 09:20:25.0 and declination +33:52:57. The system is at a distance of 225 parsecs from us.

The brightest stars in the plot have magnitude 1 and the faintest have magnitude 6. WASP-13 has a visual magnitude of 10.4, and so is much fainter than these stars. You would need a telescope to see it.

WASP-13b is in an aligned orbit. That means that it orbits above the equator of the star.

Observations of WASP-13b with NASA’s Hubble Space Telescope told us that the star and planet are about 5 billions years old.

Observations with the 10-metre Keck telescopes in Hawaii helped to tell us the mass and radius of the planet.

Observations with the Spitzer Space Telescope detected the heat of the planet, watching it disappear as it passed behind the star.

The discovery of WASP-13 was announced in 2009 in a paper led by Ian Skillen of the Isaac Newton Group of telescopes on La Palma, in the Canary Islands, where some of the first observations of WASP-13 were made.


The La Palma Observatory is also the home of the SuperWASP-North array of cameras that first detected transits of WASP-13b.

For more information visit http://exoplanet.eu/catalog/wasp-13_b/.