| WASP-8b | |
| Discoverer: | Cameron et al. (SuperWASP) |
| Discovered: | April 1, 2008 |
| Discovery Method: | Transit |
| Star: | WASP-8 |
| Surface Grav: | (4.34 g) |
| Single Temperature: | (1552K) |
WASP-8b is an exoplanet orbiting the star WASP-8A in the constellation of Sculptor. The star is similar to the Sun and forms a binary star with a red dwarf star (WASP-8B) of half the Sun's mass that orbits WASP-8A 4.5 arcseconds away. The system is 294lk=onNaNlk=on away and is therefore located closer to Earth than many other star systems that are known to feature planets similar to WASP-8b. The planet and its parent star were discovered in the SuperWASP batch -6b to -15b. On 1 April 2008, Dr. Don Pollacco of Queen's University Belfast announced them at the RAS National Astronomy Meeting (NAM 2008).[1]
The planet orbits WASP-8A at an average distance of just 0.08lk=onNaNlk=on and a year passes in slightly more than 8.1 days on WASP-8b, which is somewhat farther from its parent star than other hot Jupiter planets. However, WASP-8b's orbit also has an relatively high eccentricity of 0.3, which, at periastron, brings it as close to its star as said similar planets are.
One thing that stands out extremely about WASP-8b is its orbit-spin angle to its star of : This implies that the planet actually orbits retrograde to the spin of the parent star.[2]
WASP-8b belongs to a class of extrasolar planets known as hot Jupiters and has a mass about 2.2 times and a radius slightly bigger than that of the planet Jupiter. Its density is about ; this implies that, unlike similar close-orbiting gas giants, the planet is actually denser than Jupiter (which has a density of).
Owing to its close distance to its star, WASP-8b is extremely hot: Its measured dayside temperature is 1552K, this is even hotter than its equilibrium temperature of 947K.