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Astron. Astrophys. 319, 274-281 (1997)

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The radiation belts of Jupiter at 13 and 22 cm

I. Observations and 3-D reconstruction

Y. Leblanc 1, G.A. Dulk 1, 2, R.J. Sault 3 and R.W. Hunstead 4

1 CNRS-URA 264, DESPA, Observatoire de Paris, F-92195 Meudon, France
2 Department of Astrophysical, Planetary and Atmospheric Sciences, University of Colorado, Boulder, CO 80309, USA
3 Australia Telescope National Facility, CSIRO, Epping, NSW 2121, Australia
4 Departement of Astrophysics, University of Sydney, NSW 2006, Australia

Received 11 April 1996 / Accepted 17 June 1996

Abstract

We present Australia Telescope observations of Jupiter in July 1995 at 13 and 22 cm with a resolution of [FORMULA] at 13 cm and [FORMULA] at 22 cm. Images averaged over 10 days of observation clearly show the two populations of energetic electrons, one concentrated at the magnetic equator, and the other reaching high latitudes. The average separation between the east and west limb peaks is 2.9  [FORMULA] at both 22 and 13 cm, and the radiation extends to 4  [FORMULA] with good signal to noise.

A 3-D reconstruction of the belts is presented, showing vividly the warping of the magnetic equator as manifested in the radiation belts around the planet, and in the mirror regions at high latitudes.

From a series of images at different longitudes, the E-W brightness distribution as a function of CML is shown in a new way, demonstrating how the brightness on the two sides of the belt changes with Jupiter rotation. The bright spot crosses the east limb when [FORMULA], located at System III longitude [FORMULA]. When it crosses the west limb, less than [FORMULA] later, the same spot is fainter.

When the E-W brightness is plotted in terms of [FORMULA], the ratio of east-to-west limb brightness takes on a simple, sinusoid-like form. The ratio is greater than unity in the [FORMULA] range 180 to [FORMULA] for these observations, made at [FORMULA]. In Paper II we relate the observations to the warping of the magnetic equator and obtain further insight into the magnetic field of Jupiter.

Key words: planets and satellites: Jupiter – continuum: solar system – techniques: image processing

Send offprint requests to: Y. Leblanc

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© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998
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