High-resolution infrared imaging of Neptune from the Keck Telescope

We present results of infrared observations of Neptune from the 10-m W M. Keck I Telescope, using both high-resolution (0.04 arc-second) broadband speckle imaging and conventional imaging with narrowband filters (0.6 arcsec resolution). The speckle data enable us to track the size and shape of infrared-bright features ("storms") as they move across the disk and to determine rotation periods for latitudes -30 and -45degrees. The narrowband data are input to a model that allows Lis to make estimates of Neptune's stratospheric haze abundance and the size of storm features. We find a haze column density of similar to10(6) cm(-2) for a haze layer located in the stratosphere, and a lower limit of 10(7) cm(-2) and an upper limit of 10(9) cm(-2) for a layer of 0.2 mum particles in the troposphere. We also calculate a lower limit of 7 x 10(6) km(2) for the size of a "storm" feature observed on 13 October 1997. (C) 2002 Elsevier Science (USA).