Limits on the Contribution of Endogenic Radiolysis to the Presence of Molecular Oxygen in Comet 67P/Churyumov-Gerasimenko

Research output: Contribution to journalArticle


Radiolytic production has been proposed as a potential source for the molecular oxygen observed in comet 67P/Churyumov-Gerasimenko. Radiolysis can be exogenic or endogenic, the latter due to radionuclides present in the dust constitutive of the comet nucleus. We investigated the possibility of forming a significant amount of molecular oxygen through endogenic radiolysis. We applied a model of radiolytic production, developed for an Earth rock-water mixture, and improved it to account for the effect of the size of a radionuclide-bearing grain on the net radiation deposited in its ice mantle. We calculated the possible production of molecular oxygen considering the available experimental values of radiolytic yields. We found that endogenic radiolysis cannot account for the totality of the 3.8% (relative to water) O2 abundance derived from the ROSINA observations, with an end member case of our model producing at most a 1% abundance. By contrast, we predict H2O2 production leads to an abundance up to two orders of magnitude above observed values.


  • Alexis Bouquet
  • Olivier Mousis
  • Benjamin Teolis
  • Georgios Nicolaou
  • Ozge Ozgurel
  • Francoise Pauzat
  • Yves Ellinger
  • Thomas Ronnet
  • J. Hunter Waite
External organisations
  • University of Texas at San Antonio
  • Southwest Research Institute (swri), Texas
  • Laboratoire d'Astrophysique de Marseille (LAM)
  • Swedish Institute of Space Physics
  • University College London
  • Versailles Saint-Quentin-en-Yvelines University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology


  • astrochemistry, comets: individual (67P/Churyumov-Gerasimenko)
Original languageEnglish
Article number9
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2018 Sep 1
Publication categoryResearch
Externally publishedYes