37th DPS Meeting, 4-9 September 2005
Session 22 Outer Planets II
Oral, Tuesday, September 6, 2005, 11:00am-12:30pm, Law LG19

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[22.03] Ammonia plumes in the Great Red Spot turbulent wake

M. H. Wong, I. de Pater (UC Berkeley)

We acquired HST/NICMOS near-infrared images of Jupiter on 25 March, 2005, with spatial resolutions of about 245 km/pixel (NIC2 camera) and 140 km/pixel (NIC1). We achieve full coverage of latitudes ±26 deg. in NIC2 (±14 deg. in NIC1) and longitudes 100 deg. to 325 deg. (System III; the GRS was visible in the first of two orbits).

A preliminary analysis suggests:

(1) The tops of convective plumes in the GRS turbulent wake show significant NH3 absorption. A linear correlation between 1.66 micron and 2.04 micron images indicates comparable continuum (H2 and CH4) absorption in these filters, but the correlation breaks down mainly in the convective plumes, where NH3 absorption at 2.04 micron is stronger.

(2) At the time of our observations, the GRS turbulent wake was organized into three lozenge-shaped cells on the order of 5000 x 13000 km, with tall cloud formation in the centers and reduced upper-level cloud opacity and/or NH3 gas abundance in the narrow cell borders.

Future modeling of these data will help increase our understanding of the formation and maintenance of the globally-averaged subsaturated ammonia gas profile on Jupiter, and perhaps also the upper-tropospheric haze, which seems to be optically thicker in the GRS turbulent wake cell centers than in the borders. Near-simultaneous observations were taken at 5 micron at the IRTF and at 2 and 3.6 cm at the VLA, in order to eventually correlate our results with deeper cloud and NH3-gas opacity.

This work was supported by the Space Telescope Science Institute, under contract with NASA.

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.