Preliminary detection of the X-ray emission from WASP18

Hot Jupiters are gas giant extrasolar planets close to their host stars. In twostellar systems with hot Jupiters, a cyclic variation of chromospheric activitysynchronized to the planet.s revolution, and not to the stellar rotation, wasobserved. The proposed mechanism to explain this activity enhancement is amagnetic interaction between the star and the hot Jupiter. The extrasolar planetWASP18b is the first confirmed hot Jupiter that has an orbital period of lessthan one day; it is orbiting only 2.6 stellar radii above the stellar surface.Moreover, WASP18 is one of the youngest known planethosting star. We propose ashort observation of WASP18 to characterize its Xray flux and temperature inorder to prepare a future longer Xray observation of this remarkable system. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]