Bibcode
Wong, Michael H.; Marchis, F.; Marchetti, E.; Amico, P.; Bouy, H.; de Pater, I.
Bibliographical reference
American Astronomical Society, DPS meeting #40, #41.14; Bulletin of the American Astronomical Society, Vol. 41, p.561
Advertised on:
1
2009
Citations
1
Refereed citations
1
Description
Jupiter was imaged during the Science Demonstration of the MCAO
Demonstrator (MAD) at the European Southern Observatory's Very Large
Telescope. Io and Europa were used as natural guide stars on either side
of Jupiter, separated from each other by about 1.6 arcmin from 23:41 to
01:32 UT (2008 Aug 16/17). The corrected angular resolution was 0.090
arcsec across the entire field of view, as measured on background stars.
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The observations in K, Kc, and BrG filters were sensitive to portions of
the Jovian spectrum with strong methane absorption. The data probe the
upper troposphere, which is populated with a fine ( 0.5 micrometer)
haze. Two haze sources have been proposed: lofting of fine cloud
particles into the stable upper troposphere, and condensation of
hydrazine produced via ammonia photochemistry. The upper tropospheric
haze is enhanced over Jupiter's equatorial region.
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Dramatic changes in the underlying cloud cover--part of the 2006/2007
"global upheaval"--may be associated with changes in the equatorial haze
distribution now evident in the 2008 MAD images. Haze reflectivity
peaked in the northern equatorial region in HST/NICMOS data from 2005,
but it now peaks in the southern equatorial region. We will present new
constraints on particles sizes and source mechanisms of the equatorial
haze, based on comparison between a diffusive transport model and
observed variation in cloud and haze distributions.
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UCB team members acknowledge the NSF Center for Adaptive Optics and the
STScI for enabling this research.