The shadow of comet Hale-Bopp in Lyman-Alpha: An absolute measurement of H production rate with SOHO/SWAN

Rosine Lallement, Jean Loup Bertaux, Karöly Szegö, Szilvia Nemeth

Research output: Contribution to journalArticle

3 Citations (Scopus)


For a few months around perihelion, the central part of the Hale-Bopp hydrogen cloud has been optically thick to the solar Lyα radiation, and has significantly reduced the solar flux available for the resonance glow of interstellar hydrogen beyond the comet. This shadowing effect on the interstellar gas is the first ever observed comet shadow. It is modeled and compared with SWAN observations. Shadow modelling will help to constrain the comet water production and radiative transfer effects in the interstellar ionisation cavity.

Original languageEnglish
Pages (from-to)67-76
Number of pages10
JournalEarth, Moon and Planets
Issue number1-4
Publication statusPublished - Mar 1 2002



  • Comets
  • Interstellar medium
  • Solar system

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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