----- Submission 1 (Fri May 16 20:44:17 GMT 2003) ----- ----- Submission 1 (Fri Jan 24 14:15:30 EST 2003) ----- Assigned ID: 803 Successfully submitted: Fri Jan 24 14:15:47 EST 2003 Lightning on the Jovian Dayside The presence of lightning on Jupiter has been known for many years. It represents an important diagnostic of atmospheric characteristics below the visible cloud tops, within the water layer at a pressure ~5 bar or more. Lightning on Jupiter is thought to be associated with convective water clouds, as on Earth, at cyclonic wind shear interfaces. Dayside detection, which would enable "routine" access to this important phenomenon, has never previously been achieved. Here, we propose an innovative use of the NICMOS MULTIACCUM rapid non-destructive readout capability, together with the very high spatial resolution afforded by NIC2 (0.075 arcsec/pixel, 250 km at Jupiter) to maximize our ability to detect and characterize Jovian lightning on the dayside of the planet. We propose two complementary observations: one to use the narrow filter centered on Paschen Alpha and the other, to use a medium band continuum filter that avoids methane absorption. By comparing these two passbands we expect to not only detect dayside lightning for the first time, but also obtain the first data on the spectrum of Jovian lightning at implicitly high spectral resolution (the F187N filter has 1% bandpass, which also further improves the contrast against reflected Solar light). This will allow us to test laboratory analogues and models for the Jovian lightning and assess in a preliminary way the region of parameter space of relevance (pressure, temperature, composition).
We will perform as many 0.203sec NICMOS SCAMRR exposures with filters F165M and F187W as possible in the one orbit of observing time awarded. We will use blind pointing to acquire Jupiter. We target latitude 49 degrees N, at the central meridian. SOLAR SYSTEM 12 false false false false SUPPORTED SOLAR SYSTEM SURF(V)=5.65 PLANET PLANET JUPITER STD=JUPITER TYPE=TORUS,LONG=0.0,LAT=49.0,RAD=71400.0,POLE_LAT=90.0 00 00 0.00 +00 00 0.00 J2000 NIC2 ACCUM Imaging No NIC2 ACCUM C:\Documents and Settings\mcgrath\Local Settings\Temp\OPVisit845.xml (Tic-Visit :proposal-id 9904 :visit-id "01" :proposal-version -1 :trans-version "20030331" :date "16-May-2003 16:42:27.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 1072208 :tdrss-contact-duration 0 ) (Tic-Obset :proposal-id 9904 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 9904 :visit-id "01" :orbit-number 1 :pcs-time 365 :si-vis-utilization 2542 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3200 :pcs-gap 0 ) true C:\Documents and Settings\mcgrath\Local Settings\Temp\OPVisit64107.xml