Steve Miller
UCL

The Role of H3+ in Planetary Atmospheres

The fundamental molecular ion H3+ plays a key role in the chemistry, energy
balance, and dynamics of the upper atmospheres of the giant planets. Since
the ion was first detected spectroscopically in the aurorae of Jupiter in
1988 - incidentally the first detection outside of the laboratory - spectra
and imaging have enormously enhanced our understanding of the Jovian
thermosphere and ionosphere, and the way this atmospheric region couples to
the planet's giant magnetosphere. Imaging in H3+ wavelengths, particularly
by Connerney and co-workers, have led to dramatically improved models of
Jupiter's magnetic field. This talk will concentrate not on imaging,
however, but the role of spectroscopy in understanding the distribution of
H3+ and its temperature variations, its role as a tracer of energetic winds,
and the way this ion provides a vital link to understanding key elements
of the coupling between the planet and its magenetosphere. It will also
discuss similarities and differences between Jupiter and the less
studied Saturn and Uranus, and pose the question: could H3+ spectroscopy be
the way to detect extra-solar super-Jupiters?