The particle and magnetic environments surrounding close-in exoplanets

A. A. Vidotto, R. Fares, M. Jardine, C. Moutou, J. F. Donati

Research output: Contribution to journalArticlepeer-review


The proper characterisation of stellar winds is essential for the study of propagation of eruptive events (flares, coronal mass ejections) and the study of space weather events on exoplanets. Here, we quantitatively investigate the nature of the stellar winds surrounding the hot Jupiters HD46375b, HD73256b, HD102195b, HD130322b, HD179949b. We simulate the three-dimensional winds of their host stars, in which we directly incorporate their observed surface magnetic fields. With that, we derive the wind properties at the position of the hot-Jupiters' orbits (temperature, velocity, magnetic field intensity and pressure). We show that the exoplanets studied here are immersed in a local stellar wind that is much denser than the local conditions encountered around the solar system planets (e.g., 5 orders of magnitude denser than the conditions experienced by the Earth). The environment surrounding these exoplanets also differs in terms of dynamics (slower stellar winds, but higher Keplerian velocities) and ambient magnetic fields (2 to 3 orders of magnitude larger than the interplanetary medium surrounding the Earth). The characterisation of the host star's wind is also crucial for the study of how the wind interacts with exoplanets. For example, we compute the exoplanetary radio emission that is released in the wind-exoplanet interaction. For the hot-Jupiters studied here, we find radio fluxes ranging from 0.02 to 0.13 mJy. These fluxes could become orders of magnitude higher when stellar eruptions impact exoplanets, increasing the potential of detecting exoplanetary radio emission.

Original languageEnglish
Pages (from-to)397-402
Number of pages6
JournalProceedings of the International Astronomical Union
Issue numberS320
Publication statusPublished - Aug 1 2015
Externally publishedYes


  • brown dwarfs
  • interplanetary medium
  • outflows
  • planets and satellites: general
  • stars: low-mass
  • stars: magnetic fields
  • stars: winds

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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