Wednesday, April 2, 2008

Last Couple of Mosaics from I24

Finally finished up reprocessing the last couple of observations from I24: a three-color global observation of Io's trailing hemisphere and a 10-frame mosaic covering the Isum-Donar-Zamama region of Io's northern trailing hemisphere.

The 24ISGLOCOL01 observation (left) was taken nearly 14 hours after Galileo's encounter with the satellite and involved numerous color filters. This observation was intended as part of a campaign to examine the changes in the dark pyroclastic deposit surrounding Pillan (just below center), then more than two years after the initial eruption, as well as to look a compositional variations on Io's surface, particularly looking for the presence of an absorption band at 0.9 microns that would reveal the presence of orthopyroxene, a common iron- and silica-rich mineral found in basaltic lavas. Note the teardrop-shaped mountain near the terminator at upper right.

The second observation is 24ISZAMAMA02, a mosaic intended to look at the Isum-Donar-Zamama-Volund region on Io. Unfortunately, many of the frames were scrambled in a manner that could not be recovered. Only 10 images out of 18 acquired are usable for this mosaic. So no Volund (and almost no Isum). But hey, Donar and Zamama shows up really well. Donar is a volcano near the center of the mosaic where lava appears to have over flowed its patera and flowed south then east. Just to the west of Donar is a teardrop-shaped dark outline. Yep, that's the outline around the mountain mentioned in the previous image. You don't see topography here, just albedo features, so obviously dark material has accumulated along the base and slope of the mountain. Zamama is the lava flow at the eastern end of the mosaic. The lava vent is at the western end of the flow (where you see the radiating lava flows), and the Zamama plume emanated from the center of the large lava flow. The earlier ZAMAMA01 observation revealed higher resolution details of this lava flow.

Don't forget to click on the names of the observations here . These will take you to higher resolution versions of these mosaics. Don't forget to check out the rest of the I24 observations here, as well as the other images I have reprocessed here.

Hope you enjoyed the April Fool's Joke from yesterday. Obviously, I was just joking about who Hillary Clinton went with on her trip to Io in 1997. She really went with her daughter Chelsea, country singer Billy Ray Cyrus, and comedian Arsenio Hall (not Vanilla Ice and Bozo the Clown).

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