EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recent Mid-Infrared Through Submillimeter Observations of Uranus and Neptune

Glenn Orton1, James Sinclair1, Leigh Fletcher2, Naomi Rowe-Gurney2, Michael Roman2, Patrick Irwin3, and Heidi Hammel4
Glenn Orton et al.
  • 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA (
  • 2University of Leicester, Leicester, UK
  • 3University of Oxford, Oxford, UK
  • 4Association of Universities for Research in Astronomy, Washington, DC

Observations of thermal emission from Uranus and Neptune have been made over a broad wavelength range from ground-based platforms, airborne observatories, Earth-proximal spacecraft and from the Voyager-2 flybys in the 1980s.  Observations since the Voyager flybys have included long-wavelength observations of disk-averaged radiances from the Infrared Space Observatory and the Herschel Space Observatory covering the far-infrared to millimeter range. We present recent airborne spectra from SOFIA covering 17-35 µm, together with Akari and Spitzer spectroscopy at wavelengths extending down to 7 µm, below which contributions from reflected sunlight and potential auroral emissions may confuse the signature of thermal emission.  We also show how these disk-averaged spectra are complemented by ground-based filtered imaging and spectroscopy at 8-10m telescopes, which have enabled spatially resolved measurements, complementing those of Voyager IRIS from several decades ago. The critical insights into the structure, chemistry and dynamics of the atmospheres of these Ice Giants attest to the need for significant parts of this spectral region to be included in the instrument complement to be assigned to spacecraft sent to these planets.  A vigorous program of Earth-based observations in the accessible spectral range should accompany the spacecraft capability in order to track potential seasonal and non-seasonal variability of these planets, as is evident in the atmospheres of both Jupiter and Saturn. The latter would include mid-infrared observations from the James Webb Space Telescope.

How to cite: Orton, G., Sinclair, J., Fletcher, L., Rowe-Gurney, N., Roman, M., Irwin, P., and Hammel, H.: Recent Mid-Infrared Through Submillimeter Observations of Uranus and Neptune, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3382,, 2021.

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