Abstract
Past observations and modeling of Jupiter's thermosphere have, due to their limited resolution, suggested that heat generated by the aurora near the poles results in a smooth thermal gradient away from these aurorae, indicating a quiescent and diffuse flow of energy within the subauroral thermosphere. Here we discuss Very Large Telescope‐Cryogenic High‐Resolution IR Echelle Spectrometer observations that reveal a small‐scale localized cooling of ~200 K within the nonauroral thermosphere. Using Infrared Telescope Facility NSFCam images, this feature is revealed to be quasi‐stable over at least a 15 year period, fixed in magnetic latitude and longitude. The size and shape of this “Great Cold Spot” vary significantly with time, strongly suggesting that it is produced by an aurorally generated weather system: the first direct evidence of a long‐term thermospheric vortex in the solar system. We discuss the implications of this spot, comparing it with short‐term temperature and density variations at Earth.
Highlights
The upper atmosphere of a planet represents an important boundary region between the underlying atmosphere and the surrounding space environment, consisting of the coexisting neutral thermosphere and charged ionosphere
We describe new observations that reveal unexpected localized variations in Jupiter’s subauroral thermosphere, suggesting that this region is dominated by complex dynamic flows and quasi-stable vortices: aurorally generated weather systems within Jupiter’s thermosphere
Even within the auroral region, where the thermosphere may be heated by very localized energy sources, the temperatures typically vary by only 100–200 K [Stallard et al, 2002; Raynaud et al, 2004]
Summary
The upper atmosphere of a planet represents an important boundary region between the underlying atmosphere and the surrounding space environment, consisting of the coexisting neutral thermosphere and charged ionosphere. Because H3+ is in quasi-thermal equilibrium in Jupiter’s ionosphere [Miller et al, 1990], variations in emission can be driven by either changes in the local H3+ density or by changes in temperature within the surrounding neutral atmosphere.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
