Magnetized winds and their influence in the escaping upper atmosphere of HD 209458b
MetadataShow full item record
Lyman a observations during an exoplanet transit have proved to be very useful to study the interaction between the stellar wind and the planetary atmosphere. They have been extensively used to constrain planetary system parameters that are not directly observed, such as the planetary mass-loss rate. In this way, Ly α observations can be a powerful tool to infer the existence of a planetarymagnetic field, since it is expected that the latterwill affect the escaping planetary material. To explore the effect that magnetic fields have on the Ly α absorption of HD 209458b, we run a set of 3D MHD simulations including dipolar magnetic fields for the planet and the star. We assume values for the surface magnetic field at the poles of the planet in the range of [0-5] G, and from 1 to 5 G at the poles of the star. Our models also include collisional and photo-ionization, radiative recombination, and an approximation for the radiation pressure. Our results show that the magnetic field of the planet and the star change the shape of the Ly α absorption profile, since it controls the extent of the planetary magnetosphere and the amount of neutralmaterial inside it. Themodel that best reproduces the absorption observed in HD 209458b (with canonical values for the stellar wind parameters) corresponds to a dipole planetary field of ≲ 1 G at the poles.
Villarreal D'Angelo , C , Esquivel , A , Schneiter , M & Sgró , M A 2018 , ' Magnetized winds and their influence in the escaping upper atmosphere of HD 209458b ' , Monthly Notices of the Royal Astronomical Society , vol. 479 , no. 3 , pp. 3115-3125 . https://doi.org/10.1093/mnras/sty1544
Monthly Notices of the Royal Astronomical Society
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at: https://doi.org/10.1093/mnras/sty1544
DescriptionCVD acknowledges STFC (ST/M001296/1) and the PhD fellowship from CONICET. MAS acknowledges support from the CONICET via an Assistant Research Fellowship. The authors want to thank the Centro de Simulación Computacional para Aplicaciones Tecnológicas - CONICET, where some of the test of the code was run. AE acknowledges support from CONACYT DGAPA-PAPIIT (UNAM) grants IN 109715 and IG 100516.
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.