A&A 460, 317-322 (2006)
DOI: 10.1051/0004-6361:20065353

A magnetic communication scenario for hot Jupiters

S. Preusse¹, A. Kopp², J. Büchner¹, and U. Motschmann<sup>3

1</sup>  Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany
    e-mail: preusse@steinbeis-europa.de;buechner@mps.mpg.de
²  Theoretische Physik IV, Ruhr-Universität Bochum, 44780 Bochum, Germany
    e-mail: ak@tp4.rub.de
³  Institut für Theoretische Physik, Technische Universität Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany
    e-mail: u.motschmann@tu-bs.de

(Received 3 April 2006 / Accepted 31 August 2006)

Abstract
The observations of enhanced chromospheric activity on HD 179949 as well as on  And with the same periods as their close-in planets seem to indicate some kind of magnetic interaction between star and planet. A constraint to any possible model are the large phase angles of and , respectively. We present a simple model, which is based on the propagation of Alfvén waves within the stellar wind flow relative to the planet and which can meet this restriction. In the solar system such a model is successfully used to explain the current system between Io and Jupiter.

Key words: planets and satellites: general -- stars: magnetic fields -- stars: winds, outflows -- stars: activity

© ESO 2006

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