YOU wait years to find an extrasolar planet orbiting in the opposite direction to its star’s spin, then two come along at once.
The two planets, WASP-17b and HAT-P-7b, are both “hot Jupiters” – gas giants that orbit very close to their stars. HAT-P-7b, which is 1.4 times as wide as Jupiter and 1.8 times as massive, is smaller and heavier than WASP-17b, which may be the biggest and least dense exoplanet found so far. The planets are about 1000 light years from us.
David Anderson of Keele University, UK, and colleagues found WASP-17b using a telescope array at the South…
