The planet WASP-34b is 1.22 times the radius of Jupiter, the largest planet in our Solar System. That makes it about 12 times the radius of Earth. WASP-34b is a large planet made of gas, whereas Earth is a small, rocky planet.

Despite being larger, WASP-34b is only half the mass of Jupiter, which means it is much less dense. That likely means that the gas insider it is warmer, since hot gases expand.

The star WASP-34 is 0.93 times the radius of the Sun and its spectral type is G5. Thus it is a bit smaller and a bit cooler than our Sun. It has a brightness of visual magnitude 10.4.

WASP-34b orbits at a distance of 7.84 million km, taking 4.3 days to go round its orbit.

WASP-34 lies in the constellation of Crater. Its coordinates are right ascension 11:01:36.0 and declination −23:51:38. The system is a distance of 130 parsecs away from us.

The brightest stars in the plot have magnitude 2 and the faintest have magnitude 6, so, with a visual magnitude 10.4, WASP-34 is much fainter than these stars. You would need a telescope to see it.

WASP-34b is in a grazing transit. That means that the path of the planet’s orbit takes it along the limb of the star, so that not all of the planet is in front of the star.

In a grazing transit the fraction of the planet that is blocking light from the star is continually changing, so the transit has a V-shaped profile like this one:

Normally, when the planet is completely on the face of the star, exoplanets produce a characteristic U-shaped transit like this one:

The discovery of WASP-34b was announced in 2011 in a paper led by Barry Smalley of Keele University in the UK. Dr Smalley is the WASP project’s expert in interpreting the spectra of the stars that WASP planets orbit. 

WASP-34 has been observed by NASA’s Spitzer Space Telescope, which observes infra-red radiation (heat). Spitzer detected a reduction in the total heat from the system when the planet passed behind the star. 

For more information visit http://exoplanet.eu/catalog/wasp-34_b/.