Juno-JIRAM: Overview of Preliminary Results in the Study of Jupiter Hot-Spots

The JIRAM instrument on board of the Juno spacecraft includes a spectrometer channel that operates in the range 2-5 ?m with a spectral resolution of about 14 nm. Data from this channel are particularly valuable in the study of the hot-spots, regions of the Jupiter atmosphere where the upper cloud decks are relatively thin and the thermal radiation emitted at pressures down to 3-4 bars can be measured by infrared remote-sensing instruments. Previous studies on NIMS-Galileo [1] and VIMS-Cassini [2] data, as well as a specific assessment for the JIRAM instrument [3], have demonstrated the possibility to constraints the content of H2O, NH3 and PH3 from moderate-resolution spectra of hot spots covering the CH4 transparency window at 5 ?m. This talk reviews the first results on the retrieval of these species from the JIRAM observations acquired around the first Juno pericenter after the orbit insertion. The specific characteristics of the orbit have made possible a fairly complete latitudinal and longitudinal coverage of the thermal emissions at low emission angles over large portions of the Jupiter disk. Maps of gas content are compared against the previous results derived from NIMS, VIMS and ISO spectra. [1] Irwin et al., 1998, doi:10.1029/98JE00948 [2] Giles et al., 2015, doi:10.1016/j.icarus.2015.05.030 [3] Grassi et al., 2010, doi:10.1016/j.pss.2010.05.003