Mid-to-Low Latitude H3 Emission from Jupiter

Abstract

by workers modeling the atmospheres of the outer planets (see, e.g., Atreya and Donahue, 1976). The Voyager II We present measurements of the mid-to-low latitude H3 emission from Jupiter, derived from a spectroscopic study of the spacecraft detected an ion with a mass:charge ratio of planet carried out on the United Kingdom Infrared Telescope 3 : 1 in Jupiter’s magnetosphere during its flyby of the (UKIRT) on Mauna Kea, Hawaii, on May 3–5, 1993. The planet in 1979 (Hamilton et al., 1980). Since its spectromeasurements indicate ionospheric H3 temperatures p800 K scopic detection in the jovian aurorae in 1988 (Drossart and column densities of the order of 10 cm. The emission et al., 1989), H 3 emission has been used to probe auroral levels depend strongly on latitude and longitude, but are generactivity and morphology using both spectroscopic and ally of the order of 10 erg s cm, indicating that the cooling imaging techniques (see review by Miller et al., 1994, effect of H3 is a significant factor in the ionosphere. These and references therein). In recent years a number of emission levels also strongly suggest either that aurorally proinfrared spectroscopic studies of Jupiter have shown that duced H3 is being transported to nonauroral latitudes or that emission from the fundamental rovibrational band of sources in addition to solar EUV are required to produce the the H 3 molecular ion may be detected from all parts ionisation and excitation energy necessary to account for the observed H3 emission. This view is supported by comparing of the planetary disk (Miller et al., 1992; de Bergh et al., the emission profiles as a function of latitude with those ob1992; Ballester et al., 1994, henceforth Paper I). This tained from a jovian global circulation model which has auroral gave rise to the expectation that H 3 emission could be electron precipitation and solar EUV as ionisation inputs. The used to probe and monitor conditions in the nonauroral spatial distribution of H3 emission suggests that this ion may ionosphere. Paper I, for instance, considered a potential be a useful probe of Jupiter’s magnetic field at subauroral link between H 3 emission and the Lyman-a Bulge, a latitudes.  1997 Academic Press region around Jupiter’s equator which shows enhanced Lyman-a emission. Also, during the collision of Comet Shoemaker–Levy 9 with Jupiter in July 1994, several

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@inproceedings{Miller1997MidtoLowLH, title={Mid-to-Low Latitude H3 Emission from Jupiter}, author={Steven Miller and N. Achilleos and Gilda E. Ballester and Jonathan Tennyson and Thomas R . Geballe and Laurence M. Trafton}, year={1997} }