Domaine de recherche:
Satellites de glace (2011 - 2016)
En cours
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   erc-logo   EXOWATER: chemical EXchanges On WATER-rich worlds: experimentation and numerical modelling

  • English version

The EXOWATER project is dedicated to the characterization of chemical exchanges within water-rich bodies including icy moons of Jupiter and Saturn (Europa, Ganymede, Titan, Enceladus)  as well as exoplanets that may be discovered in a near future by ground-based and space-born observations. The objective of this project is to quantify the interactions between the different layers composing these water-rich interiors (silicate mantle, oceans, ice shells)  by combining both experimentation and numerical modeling. This approach will permit us to constrain the impact of  the interior on the chemical evolution of the subsurface ocean, surface and atmosphere and will help to determine if such water-rich environments are suitable for life development.

  • Version française

Le projet EXOWATER est dédié à la caractérisation des échanges chimiques dans les corps riches en eau  tels que les satellites de glace de Jupiter et Saturne (Europe, Ganymède, Titan, Encelade) ainsi que les exoplanètes que l'on devrait découvrir dans un futur proche à partir des programmes d'observations au sol et dans l'espace. L'objectif de ce projet est de quantifier les interactions entre les différents couches composant leurs intérieurs riche en eau (manteau silicaté, océan, couches de glace) en combinant expérimentation et modélisation numérique.  Cette approche permettra de contraindre l'impact de l'intérieur sur l'évolution chimique des océans souterrains, de la surface et de l'atmosphère de ces objets, et aidera à déterminer si ces environnements riche en eau sont propices au développement de la vie.



The EXOWATER project is dedicated to the characterization of chemical exchanges within water-rich bodies including icy moons of Jupiter and Saturn as well as exoplanets that may be discovered in a near future by ground-based and space-born observations. Recent exploration missions, Galileo (1996-2003) and Cassini- Huygens (2004-today), have revealed that the moons of Jupiter and Saturn are very enigmatic objects, introducing extraordinary challenges for geologists, astrobiologists, organic chemists, and planetologists. A series of  observational evidence indicate that several of these moons possess extensive liquid water reservoir beneath their cold icy surface. The presence of salted materials on the surface of Jupiter’s moon Europa, the occurrence of vapour jets on Saturn’s moon Enceladus as well as the existence of methane-rich atmosphere on Saturn’s moon Titan witness that chemical exchanges between their silicate warm inner core and their water-rich outer layer have occurred and are probably still occurring. Similar exchange processes are also likely to occur within water-rich planets outside our Solar System. Continuous progresses in detection technique should make possible to detect such water-rich planets and to get first clues on their composition in the mid-term future. In this project, I propose to develop a new and innovative approach combining experimental works and numerical modelling in order to be able to interpret the different sets of data that are and will be acquired on both icy moons and exoplanets.


Even though these water-rich environments are often considered as possible habitats for life, no precise quantification of the chemical complexity of such environments has been done so far. Exchange processes have probably varied along the body evolution, and what we observe nowadays on their surface or in their atmosphere is the integrated result of several billion years of complex interactions. In absence of a precise quantification of these chemical exchanges, it is impossible to evaluate the exobiological potential of these water-rich environments. Before answering if these water-rich worlds are suitable for the development of life, several fundamental questions need to be solved:

  • What is the degree of chemical exchanges between their different envelopes ?
  • What are the chemico-physical variations in their interiors since their formation ?
  • Can we infer the composition of their water-rich layers from surface and atmosphere signatures ?

In the present project, we address these unresolved key questions through three science investigations:

1. Investigate the stability of gas compounds in these water-rich interiors, the conditions for which they can be incorporated in clathrate structures and what are their spectral signatures, permitting their identification on planetary surfaces.

2. Investigate the coupled chemical evolution of ocean and atmosphere, the post-accretional cooling of the ocean and atmosphere, and the composition of the atmosphere and crust resulting from these interactions, including the fate of volatile compounds.

3. Investigate the transport of various chemical species and materials through the icy mantles and crust, in solid and/or liquid state, how this transport affects the composition of the internal ocean and what physical processes may deliver oceanic materials to the surface.


This innovative approach will provide the first complete description of exchange processes on water-rich bodies. This will permit to quantify the degree of interaction between seafloors, oceans, ice shells, and surfaces of icy worlds, and will thus provide key constraints on the chemistry of their interior and in particular on the chemical and physical properties on their internal ocean. This will improve our understanding of icy world ocean environmental conditions, and help to determine if such environments are suitable for life development.

The modeling of interactions between the interior and surface will also provide first- rate tools for the interpretation of Galileo/Cassini observations and will significantly improve our current understanding of planetary processes. The output of these numerical simulations will help for the definition of measurements that should be done by future exploration missions (Europa and Jupiter System Mission, and Titan and Saturn System Mission) in order to constrain the composition of icy moon ocean.

The detection of water-rich around other stars is within our reach. When the first detections of a water-rich planet and the first identification of atmospheric components will occur, my proposed modelling efforts will provide a theoretical framework for the data interpretation in term of physical and chemical conditions of their ocean and atmosphere. This will provide key constraints to define if a detected planet outside our solar system is a good candidate for life development.