Exoplanet transit variability: Bow shocks and winds around HD 189733b

J. Llama, A. A. Vidotto, M. Jardine, K. Wood, R. Fares, T. I. Gombosi

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)


By analogy with the Solar system, it is believed that stellar winds will form bow shocks around exoplanets. For hot Jupiters the bow shock will not form directly between the planet and the star, causing an asymmetric distribution of mass around the exoplanet and hence an asymmetric transit. As the planet orbits through varying wind conditions, the strength and geometry of its bow shock will change, thus producing transits of varying shape. We model this process using magnetic maps of HD 189733 taken one year apart, coupled with a 3D stellar wind model, to determine the local stellar wind conditions throughout the orbital path of the planet. We predict the time-varying geometry and density of the bow shock that forms around the magnetosphere of the planet and simulate transit light curves. Depending on the nature of the stellar magnetic field, and hence its wind, we find that both the transit duration and ingress time can vary when compared to optical light curves.We conclude that consecutive near-UV transit light curves may vary significantly and can therefore provide an insight into the structure and evolution of the stellar wind.

Original languageEnglish
Pages (from-to)2179-2187
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - Dec 2013
Externally publishedYes


  • General - planets and satellites
  • HD 189733 - stars
  • HD 189733b - planets and satellites
  • Individual
  • Magnetic fields - planet-star interactions - stars
  • Outflows.
  • Planets and satellites
  • Winds

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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