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Interplanetary magnetic field orientation and the magnetospheres of close-in exoplanets

Johannsson, E. P. G. and Mueller, J. and Motschmann, U. (2011) Interplanetary magnetic field orientation and the magnetospheres of close-in exoplanets. Astronomy and Astrophysics, 525 (A117), p. 14802. EDP Sciences. DOI: 10.1051/0004-6361/201014802. ISSN 0004-6361.

Full text not available from this repository.

Abstract

The abundance of exoplanets with orbits smaller than that of Mercury most likely implies that there are exoplanets exposed to a quasiparallel stellar-wind magnetic field. Many of the generic features of stellar-wind interaction depend on the existence of a nonzero perpendicular interplanetary magnetic field component. However, for closer orbits the perpendicular component becomes smaller and smaller. The resulting quasiparallel interplanetary magnetic field may imply new types of magnetospheres and interactions not seen in the solar system. We simulate the Venus-like interaction between a supersonic stellar wind and an Earth-sized, unmagnetized terrestrial planet with ionosphere, orbiting a Sun-like star at 0.2 AU. The importance of a quasiparallel stellar-wind interaction is then studied by comparing three simulation runs with different angles between stellar wind direction and interplanetary magnetic field. The plasma simulation code is a hybrid code, representing ions as particles and electrons as a massless, charge-neutralizing adiabatic fluid. Apart from being able to observe generic features of supersonic stellar-wind interaction we observe the following changes and trends when reducing the angle between stellar wind and interplanetary magnetic field 1) that a large part of the bow shock is replaced by an unstable quasiparallel bow shock; 2) weakening magnetic draping and pile-up; 3) the creation of a second, flanking current sheet due to the need for the interplanetary magnetic field lines to connect to almost antiparallel draped field lines; 4) stellar wind reaching deeper into the dayside ionosphere; and 5) a decreasing ionospheric mass loss. The speed of the last two trends seems to accelerate at low angles.

Document Type:Article
Title:Interplanetary magnetic field orientation and the magnetospheres of close-in exoplanets
Authors:
AuthorsInstitution or Email of Authors
Johannsson, E. P. G. Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
Mueller, J.Institute for Theoretical Physics, TU Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany
Motschmann, U.Institute for Theoretical Physics, TU Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany; uwe.motschmann@dlr.de
Date:2011
Journal or Publication Title:Astronomy and Astrophysics
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:525
DOI:10.1051/0004-6361/201014802
Page Range:p. 14802
Publisher:EDP Sciences
ISSN:0004-6361
Status:Published
Keywords:plasmas, planetary systems, stars, winds, outflows, magnetic fields
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EW - Erforschung des Weltraums
DLR - Research area:Space
DLR - Program:W EW - Erforschung des Weltraums
DLR - Research theme (Project):W - Vorhaben Exploration des Sonnensystems (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Asteroids and Comets
Deposited By: Laura-Maria Brumm
Deposited On:17 Jun 2011 13:52
Last Modified:07 Feb 2013 20:50

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