YOU wait years to find an extrasolar planet orbiting in the opposite direction to its star鈥檚 spin, then two come along at once.
The two planets, and , are both 鈥渉ot Jupiters鈥� 鈥� 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 near Sutherland.
Advertisement
HAT-P-7b was discovered by two independent teams, one led by Joshua Winn of the Massachusetts Institute of Technology, and the other by Norio Narita at the National Astronomical Observatory of Japan. They both used the Japanese atop Mauna Kea in Hawaii.
Although both teams agree that HAT-P-7b is orbiting backwards, its orbit is tilted with respect to its star鈥檚 equator, and the two teams disagree on the degree of tilt. 鈥淲e鈥檙e catching so many planets these days, we鈥檙e bound to see some of the oddballs,鈥� says Adam Burrows of Princeton University.