Magnetized winds and their influence in the escaping upper atmosphere of HD 209458b

VILLARREAL DANGELO, CAROLINA; ESQUIVEL, ALEJANDRO; SCHNEITER, MATÍAS; SGRÓ, MARIO AGUSTÍN

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 vol. 479 p. 3115 - 3115

0035-8711

yman α observations during an exoplanet transit have proved to bevery useful to study the interaction between the stellar wind and theplanetary atmosphere. They have been extensively used to constrainplanetary system parameters that are not directly observed, such as theplanetary mass-loss rate. In this way, Ly α observations can be apowerful tool to infer the existence of a planetary magnetic field,since it is expected that the latter will affect the escaping planetarymaterial. To explore the effect that magnetic fields have on the Lyα absorption of HD 209458b, we run a set of 3D MHD simulationsincluding dipolar magnetic fields for the planet and the star. We assumevalues for the surface magnetic field at the poles of the planet in therange of [0-5] G, and from 1 to 5 G at the poles of the star. Our modelsalso include collisional and photo-ionization, radiative recombination,and an approximation for the radiation pressure. Our results show thatthe magnetic field of the