Stuttgart 2012 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 3: Astrobiologie
EP 3.6: Talk
Tuesday, March 13, 2012, 15:30–15:45, V55.02
Magnetospheres of hot giant exoplanets: structure, scaling, observations — •Maxim Khodachenko1, Igor Alexeev2, Elena Belenkaya2, Helmut Lammer1, and Helmut Rucker1 — 1Space Research Institute, Austrian Academy of Sciences, Graz, A-8042, Austria — 2SINP, Moscow State University, Moscow, 119992, Russia
A more complete view of a magnetosphere of a close orbit giant exoplanet, based on the Paraboloid Magnetospheric Model (PMM), is proposed. Besides of the intrinsic planetary magnetic dipole, PMM considers among the main magnetic field sources also the electric current system of magnetotail, magnetopause currents, and the ring current of magnetodisk. The key element of the considered model consists in taking into account the effects of expanding upper atmosphere of a Hot Jupiter heated by the stellar XUV radiation. The escaping atmospheric material is ionized and builds up an extended magnetodisk around the planet. The magnetic field produced by magnetodisk ring currents, dominates above the contribution of intrinsic magnetic dipole of a Hot Jupiter and finally determines the size and shape of the whole magnetosphere. It is 40 - 70 % larger than that, traditionally estimated for the case of only the planetary dipole taken into account. The size and shape of the magnetospheric obstacle of an exoplanet influence the character of the exoplanet transit curve in EUV and in specific spectral lines. This opens a way for observational probing of exoplanetary magnetospheres and stellar winds parameters.