DPS 2001 meeting, November 2001
Session 22. Outer Planet Atmospheres II: Chemistry and Thermal Structure
Oral, Chairs: K. Rages, J. Moses, Wednesday, November 28, 2001, 3:00-4:30pm, Regency E

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[22.05] The Morphology and Motions of storm features on Neptune on minute and hour timescales

S.C. Martin, I. de Pater, H. Roe (UC Berkeley), B. Macintosh, S. Gibbard, C.E. Max (IGPP/LLNL)

We present the results of a diffraction limited imaging experiment conducted August 20 and 21, 2001 UT, using the NIRSPEC/AO system on the W. M. Keck II telescope. Images were taken in H band (1.4-1.8 microns) with a resolution of .07 arcseconds. Bright, persistent features at 12 latitudes were tracked to determine the latitudinal wind profile. The wind profile is in general agreement with a smooth fit to Voyager data. The morphologic evolution of three features or collections of features are presented: a south polar feature, a group of small bright features (10 to 25 deg S) and a bright "dot" at the south pole. The south polar feature is present in all images at the cusp of a bright circumpolar band (60-70 deg S) but was seen to grow in size and intensity during the 28 hours spanned by observations. The collection of bright features just south of the equator spanned 3 cloud bands yet appeared to move as a cohesive group. The three brightest features each lie at the northern edge of a dark oval (i.e., dark at these infrared wavelengths). Each dark oval is surrounded by bright cloud bands and is approximately 900 km across. The feature best described as a ``dot" at the south pole does not seem to move from the south pole. (A similar feature was seen in Voyager images.) This feature along with inner moons of Neptune were used for image navigation. These navigational tools allowed for fine scale measurements of small features to study small oscillations in latitude and longitude over minute timescales.

This research was supported in part by the STC Program of the National Science Foundation under Agreement No. AST-9876783, and in part under the auspices of the US Department of Energy at Lawrence Livermore National Laboratory, Univ. of Calif. under contract No. W-7405-Eng-48. Data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among 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.

The author(s) of this abstract have provided an email address for comments about the abstract: smartin@astron.berkeley.edu

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