Observability of hydrogen-rich exospheres in Earth-like exoplanets

  title={Observability of hydrogen-rich exospheres in Earth-like exoplanets},
  author={Leonardo A. dos Santos and Vincent Bourrier and David Ehrenreich and Shingo Kameda},
  journal={Astronomy \& Astrophysics},
Context. The existence of an extended neutral hydrogen exosphere around small planets can be used as evidence of the presence of water in their lower atmosphere, but, to date, such a feature has not been securely detected in rocky exoplanets. Planetary exospheres can be observed using transit spectroscopy of the Lyman-α line, which is limited mainly by interstellar medium absorption in the core of the line, and airglow contamination from the geocorona when using low-orbit space telescopes. Aims… 
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