Atmospheres of the Giant Planets 401
FIGURE 13 (a) Contours of magnetic field magnitude (gauss)
on the surface of Jupiter (using the GSFC Model D 4 ). (b)
Contours of constant magnetic field on the upper atmosphere of
Uranus, along with the location of the auroral oval and the lines
connected to the orbit of the satellite Miranda (Model Q 3 ). The
magnetic dip equator is the location where the field lines are
tangent to the surface. (c) Contours of constant magnetic field
magnitude and pole locations (circled cross and dot) for Neptune
(Model O 8 ). (From J. Connerney, 1993,J. Geophys. Res. 98 ,
18,659–18,679. Copyright American Geophysical Union.)
FIGURE 14 (Top) Image of Jupiter at ultraviolet wavelengths
taken with the Wide Field and Planetary Camera 2 on the
Hubble Space Telescope. Bright auroral ovals can be seen against
the dark UV-absorbing haze and in the polar regions. Jupiter’s
north magnetic pole is tilted toward Earth, making it easier to
see the northern auroral oval as well as some diffuse emission
inside the oval. Small bright spots just outside the oval in both
hemispheres are at the location of the magnetic field lines
connecting to Io, depicted by a blue curve. Io is dark at UV
wavelengths. (Bottom) Image taken a few minutes after the one
above in a filter that samples the violet part of the spectrum just
within the range that the human eye can detect. The Great Red
Spot appears dark at this wavelength and can just be seen in the
top image as well. Io’s small disk appears here along the blue
curve, which traces the magnetic field lines in which it is
embedded. (Courtesy of J. Trauger and J. Clarke.)