H3+ Measurements in the Jovian Atmosphere with JIRAM/Juno
Mura, A. ; Migliorini, A. ; Dinelli, B. M. ; ...Olivieri, A. ; ...Plainaki, C.
Dec - 2017

Event Title : 2017 AGU Fall Meeting
Published in: American Geophysical Union, Fall Meeting 2017
Publisher: AGU
type: Conference Proceedings

Abstract
The NASA Juno mission has been investigating Jupiter's atmosphere since August 2016, providing unprecedented insights into the giant planet. The Jupiter Infrared Auroral Mapper (JIRAM) experiment, on board Juno, performed spectroscopic observations of the H3+ emissions both in the auroral regions (Dinelli et al., 2017; Adriani et al., 2017; Mura et al., 2017) and at mid latitudes. In the present work, we analyse the observations acquired by the JIRAM spectrometer during the first perijove passage on 26-27 August 2016, when the spacecraft was at about 500,000-1,200,000 km (7-17 RJ) from the planet. During a portion of the observations, the slit of the spectrometer sampled Jupiter's limb in the latitude range from 30° to 60° in both hemispheres. The limb spectra show the typical features of the H3+ emission in the 3-4 μm spectral range, which are generally used to retrieve the H3+ concentration and temperature in the auroral region. In this work we employ above spectral region to provide new insight into the H3+ vertical distribution. The spatial resolution of the limb observations of Jupiter, ranging between 50 and 130 km, is favorable for investigating the vertical distribution of H3+. The vertical profiles of the H3+ limb intensity will be presented along with the preliminary results of the retrieval on H3+ vertical volume mixing ratio (VMR) height profiles, and comparison with predictions from the available atmospheric models of the planet. Possible variability of the altitude of the peak emission with respect to latitude and longitude will also be discussed.

keywords : 2756 Planetary magnetospheres, MAGNETOSPHERIC PHYSICS, 5704 Atmospheres, PLANETARY SCIENCES: FLUID PLANETS, 5724 Interiors, PLANETARY SCIENCES: FLUID PLANETS, 6220 Jupiter, PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS