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Published June 2011 | public
Journal Article

Keck adaptive optics images of Jupiter's north polar cap and Northern Red Oval

Abstract

We present observations at near-infrared wavelengths (1–5 μm) of Jupiter's north polar region and Northern Red Oval (NN-LRS-1). The observations were taken with the near-infrared camera NIRC2 coupled to the adaptive optics system on the 10-m W.M. Keck Telescope on UT 21 August 2010. At 5-μm Jupiter's disk reveals considerable structure, including small bright rings which appear to surround all small vortices. It is striking, though, that no such ring is seen around the Northern Red Oval. In de Pater et al. [2010a. Icarus 210, 742–762], we showed that such rings also exist around all small vortices in Jupiter's southern hemisphere, and are absent around the Great Red Spot and Red Oval BA. We show here that the vertical structure and extent of the Northern Red Oval is very similar to that of Jupiter's Red Oval BA. These new observations of the Northern Red Oval, therefore, support the idea of a dichotomy between small and large anticyclones, in which ovals larger than about two Rossby deformation radii do not have 5-μm bright rings. In de Pater et al. [2010a. Icarus 210, 742–762], we explained this difference in terms of the secondary circulations within the vortices. We further compare the brightness distribution of our new 5-μm images with previously published radio observations of Jupiter, highlighting the depletion of NH_3 gas over areas that are bright at 5 μm.

Additional Information

© 2011 Elsevier. Received 17 December 2010, Revised 28 February 2011, Accepted 4 March 2011, Available online 21 March 2011. All data were obtained with the W.M. Keck Observatory, which is operated by the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. We benefitted greatly from the use of JPL's Horizons system and SETI's Planetary Rings Node. The authors extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, none of the observations presented would have been possible.

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023