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

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