A Shift in Jupiter's Equatorial Haze Distribution Imaged with the Multi-Conjugate Adaptive Optics Demonstrator at the VLT

Wong, Michael H.; Marchis, F.; Marchetti, E.; Amico, P.; Bouy, H.; de Pater, I.
Referencia bibliográfica

American Astronomical Society, DPS meeting #40, #41.14; Bulletin of the American Astronomical Society, Vol. 41, p.561

Fecha de publicación:
1
2009
Número de autores
6
Número de autores del IAC
1
Número de citas
1
Número de citas referidas
1
Descripción
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. --- 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. --- 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. --- UCB team members acknowledge the NSF Center for Adaptive Optics and the STScI for enabling this research.