EGU21-7798, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Tracing the Origins of the Ice Giants through Noble Gas Isotopic Composition

Kathleen Mandt1, Olivier Mousis2, Jonathan Lunine3, Bernard Marty4, Thomas Smith5, Adrienn Luspay-Kuti1, and Artem Aguichine2
Kathleen Mandt et al.
  • 1JHU Applied Physics Laboratory, Laurel, United States of America (
  • 2Aix Marseille Université, CNRS, CNES, LAM (Laboratoire d'Astrophysique de Marseille), Marseille, France
  • 3Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca NY 14853, USA
  • 4Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, CNRS & Université de Lorraine, Vandoeuvre-lès-Nancy, France
  • 5Chinese Academy of Sciences, Beijing, China

The current composition of giant planet atmospheres provides information on how such planets formed, and on the origin of the solid building blocks that contributed to their formation. Noble gas abundances and their isotope ratios are among the most valuable pieces of evidence for tracing the origin of the materials from which the giant planets formed. In this review we first outline the current state of knowledge for heavy element abundances in the giant planets and explain what is currently understood about the reservoirs of icy building blocks that could have contributed to the formation of the Ice Giants. We then outline how noble gas isotope ratios have provided details on the original sources of noble gases in various materials throughout the solar system. We follow this with a discussion on how noble gases are trapped in ice and rock that later became the building blocks for the giant planets and how the heavy element abundances could have been locally enriched in the protosolar nebula. We then provide a review of the current state of knowledge of noble gas abundances and isotope ratios in various solar system reservoirs, and discuss measurements needed to understand the origin of the ice giants. Finally, we outline how formation and interior evolution will influence the noble gas abundances and isotope ratios observed in the ice giants today. Measurements that a future atmospheric probe will need to make include (1) the 3He/4He isotope ratio to help constrain the protosolar D/H and 3He/4He; (2) the 20Ne/22Ne and 21Ne/22Ne to separate primordial noble gas reservoirs similar to the approach used in studying meteorites; (3) the Kr/Ar and Xe/Ar to determine if the building blocks were Jupiter-like or similar to 67P/C-G and Chondrites; (4) the krypton isotope ratios for the first giant planet observations of these isotopes; and (5) the xenon isotopes for comparison with the wide range of values represented by solar system reservoirs.

Mandt, K. E., Mousis, O., Lunine, J., Marty, B., Smith, T., Luspay-Kuti, A., & Aguichine, A. (2020). Tracing the origins of the ice giants through noble gas isotopic composition. Space Science Reviews, 216(5), 1-37.

How to cite: Mandt, K., Mousis, O., Lunine, J., Marty, B., Smith, T., Luspay-Kuti, A., and Aguichine, A.: Tracing the Origins of the Ice Giants through Noble Gas Isotopic Composition, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7798,, 2021.

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