Super-adiabatic Temperature Gradient at Jupiter’s Equatorial Zone and Implications for the Water Abundance
- 1University of Michigan, Climate and Space Sciences and Engineering, Ann Arbor, United States of America
- 2Columbia University, New York, NY, USA
- 3School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK
- 4California Institute of Technology
- 5Observatoire de la Côte d'Azur, France
- 6University of Houston, USA
- 7Department of Astronomy, Cornell University, USA
- 8Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA, Leiden, The Netherlands
- 9Jet Propulsion Laboratory, California Institute of Technology, USA
- 10Georgia Institute of Technology, USA
- 11Waite Science LLC, USA
- 12SETI Institute, USA
- 13Southwest Research Institute, USA
The temperature structure of a giant planet was traditionally thought to be an adiabat because convective mixing homogenizes entropy. The only in-situ measurement made by the Galileo Probe detected a near-adiabatic temperature structure within one of Jupiter’s 5 hot spots with small but definite local departures from adiabaticity. We analyze Juno’s microwave observations near Jupiter’s equator (0 ~ 5 oN) and find that the equatorial temperature structure is best characterized by a stable super-adiabatic temperature profile rather than an adiabatic one. Water is the only substance with sufficient abundance to alter the atmosphere's mean molecular weight and prevent dynamic instability if a super-adiabatic temperature gradient exists. Thus, from the super-adiabaticity, our results indicate a water concentration (or the oxygen to hydrogen ratio) of about 4 times solar with a possible range of 2 ~ 7 times solar in Jupiter’s equatorial region.
How to cite: Li, C., Allison, M., Atreya, S., Fletcher, L., Ingersoll, A., Guillot, T., Li, L., Lunine, J., Miguel, Y., Orton, G., Oyafuso, F., Steffes, P., Waite, H., Wong, M., Zhang, Z., Levin, S., and Bolton, S.: Super-adiabatic Temperature Gradient at Jupiter’s Equatorial Zone and Implications for the Water Abundance, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14359, https://doi.org/10.5194/egusphere-egu24-14359, 2024.
