Probing the extended atmosphere of the evaporating exoplanet HD189733b

HST observations show that two of the brightest transiting exoplanets areevaporating (HD209458b & HD189733b) and models suggest that the evolution ofclosein planets may be dominated by this mass loss. Xray observations duringthe transits of evaporating planets have the potential to detect absorption bythe inner lowvelocity regions of the planetary winds that are hidden to HST byinterstellar absorption and geocoronal emission. Detections of these dense innerregions are needed in order to determine the dynamics of the planetary outflowand measure the mass loss rates. We propose an intense campaign of XMMNewtontransit observations of the most favourable target, HD189733b, with the aim ofdetecting the extended atmosphere of the planet and measuring its mass loss rate. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]