ES-03-0019

Large-scale structures in the stellar wind of fast-rotating stars spawned by the presence of Earth-like planets. AB Doradus as a test star

Ada Canet

Forming planets around young, fast-rotating solar-like stars are exposed to an extreme XUV radiation field and strongly magnetized stellar winds, as a consequence of the high magnetic activity of these stars. Under these conditions, Earth-like exoplanets may experience a rapid loss of their primordial hydrogen atmospheres, resulting in atmosphere-less rocky obstacles for the propagating stellar winds. The interaction of stellar winds with those planets leads to the formation of potentially observable structures due to the formation of large-scale magnetic field and density disturbances in the vicinity of these planets, such as bow shocks, induced magnetospheres and comet-like tails. In this work, we study the interaction between the stellar winds of active, fast-rotating solar-like stars in the superfast-magnetosonic regime with Earth-like, unmagnetized planetary obstacles through numerical 2.5D simulations using the PLUTO MHD code. The case of study is AB Doradus, a nearby young star with a small rotation period (0.51 days) and a strong flaring activity. Bow shock and induced magnetosphere formation are parameterized through the alfvénic Mach number ???? of the wind, for different stellar wind configurations. Extremely large bow shocks, up to an extension of 140 planetary radii are found for low-???? winds. The general increase of density, temperature and magnetic field in these large-scale structures formed around planets may result in detectable spectral signatures.