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NASA's Juno spacecraft has been orbiting Jupiter since August 2016, providing unprecedented insights into the giant planet's atmosphere. The Jupiter Infrared Auroral Mapper (JIRAM) experiment on board Juno has made spectroscopic observations of the trihydrogen cation (H3+) emissions in both northern and southern auroral regions (Dinelli et al., 2017; Adriani et al., 2017; Mura et al., 2017) and at mid-to-low latitudes (this paper). Observations targeting the limb of the planet from 60° North to 60° South latitudes were acquired with JIRAM's spectrometer in August 2016 and March 2017. We use these observations to characterize, for the first time, the vertical distribution of the H3+ emissions as a function of latitude across Jupiter's dayside. H3+ emission features in the 3-4 μm spectral band were used to retrieve the H3+ volume mixing ratio (VMR) and atmospheric temperatures as a function of altitude. The H3+ density profile has a quasi-symmetric distribution with latitude, decreasing from 5 × 104 cm-3 at 300 km to 2 × 103 cm-3 at 650 km altitude above the 1-bar level (column densities of 3.5 × 1012 cm-2 to 1.4 × 1011 cm-2, assuming a 700 km column depth). The H3+ VMR is higher in the Southern hemisphere than in the North with values at 500 km of 4 × 10-4 ppmv at 40°N and 8 × 10-4 ppmv at 40°S. Retrieved temperatures increase almost monotonically with increasing altitude, hovering around 400 K at 300 km and >900 K at about 700 km.

We performed spectral analyses on four serendipitous observations of Europa acquired by the JIRAM instrument (Adriani et al., 2017) onboard the Juno mission. Due to the fixed orientation of the spacecraft spin axis and orbital plane placed along terminator, Europa is observed at approximately 90° phase angle from distances >3.35E5 km resulting in a best spatial resolution of 80 km/px. The one thousand spectra dataset returned to the ground offers a limited coverage in longitude but an almost complete excursion in latitude from poles to equator. With a 2 to 5 μm spectral range and a sampling of about 10 nm/band, JIRAM reflectance spectra allow extraction of different spectral indicators suitable to characterize surface composition, grain size distribution and temperature: the 2 μm water ice band center appears on average centered at 2.038 μm as a result of the presence of both amorphous and crystalline ice phases and non-ice materials. The reflectance level on the 2.4 μm inflection shoulder is comparable to the maximum absorption on the 2 μm band pointing to the presence of non-ice materials, like magnesium chlorinated or hydrated magnesium salts, mixed with water ice. Assuming water ice as the principal endmember, weestimate the surface regolith grain size by comparing the 2 μm band depth and the ratio between I/F at 3.63 and 2.27 μm (Filacchione et al., 2012). On average, we measure values of 0.6 for the first and 0.1 for the latter: such values are compatible with grain sizes in the range of tens to hundreds of microns. Despite the low signal-to-noise beyond 2.7 μm, due to the intrinsic low-reflectance of Europa's surface and very high phase angle values occurring during the observations, JIRAM is able to measure the wavelength of the reflectance peak around 3.6 μm, which is a proxy of water ice temperature (Filacchione et al., 2016a). In the dataset JIRAM has obtained the peak's maximum wavelength occurs at 3.64 μm corresponding to a maximum diurnal temperature of 132 K.

International audience; One of the striking features about Venus atmosphere is its temporal variability and dynamics, with a chaotic polar vortex, large-scale atmospheric waves, sheared features and variable winds that depend on local time and possibly orographic features. The aim of this research is to combine data accumulated over several years and obtain a global mean state of the atmosphere focusing in the global structure of the clouds using the cloud opacity and upper cloud temperatures.We have first produced global maps using the integrated radiance through the infrared atmospheric windows centred around 1.74 μm and 2.25 μm, that show the spatial variations of the cloud opacity in the lower clouds around 44–48 km altitude and also provide an indirect estimation of the possible particle size. We have also produced similar global maps using the brightness temperatures seen in the thermal region at 3.8 μm and 5.0 μm, which provide direct indication of the temperatures at the top of the clouds around 60–70 km altitude.These maps have been generated using the complete dataset of the Visible and InfraRed Thermal Imaging Spectrometer mapping channel (VIRTIS-M) on board Venus Express, with a wide spatial and long temporal coverage in the period from May 2006 until October 2008.Our results provide a global view of the cloud opacity, particle size and upper cloud temperatures at both hemispheres, showing the main different dynamical regions of the planet. The profiles obtained also provide the detailed dependencies with latitude, local time and longitude, diagnostic of the global circulation flow and dynamics at various altitude layers, from about 44 up to 70 km over the surface.

The Jovian InfraRed Auroral Mapper (JIRAM) on board the NASA Juno spacecraft is a dual-band imager and spectrometer, primarily designed to study the Jovian atmosphere and aurorae. In addition to its primary goal, JIRAM has been used to obtain images and spectra of the Galilean satellites, Jupiter's largest moons, when the spacecraft attitude was favourable to achieve this goal. Here we present JIRAM's first images and spectra of Io. These observations are used to characterize the location and possible morphology, and some temperatures, of Io's volcanic thermal sources; the identification of SO2 and the possible identification of other materials. A new hot spot/volcano is identified close to the South Pole of Io, and others are seen in lower latitude regions, which were previously unmapped. Images of the same region taken 2 months apart also show variations of hot spot intensity, possibly due to new lava flows or to lava flow breakouts.

The European Space Agency’s Rosetta spacecraft is the first Solar System mission to include instrumentation capable of measuring planetary thermal fluxes at both near-IR (VIRTIS) and submillimeter–millimeter (smm–mm, MIRO) wavelengths. Its primary mission is a 1 year reconnaissance of Comet 67P/Churyumov–Gerasimenko beginning in 2014. During a 2010 close fly-by of Asteroid 21 Lutetia, the VIRTIS and MIRO instruments provided complementary data that have been analyzed to produce a consistent model of Lutetia’s surface layer thermal and electrical properties, including a physical model of self-heating. VIRTIS dayside measurements provided highly resolved 1 K accuracy surface temperatures that required a low thermal inertia, I 2 s 0.5 ). MIRO smm and mm measurements of polar night thermal fluxes produced constraints on Lutetia’s subsurface thermal properties to depths comparable to the seasonal thermal wave, yielding a model of I 2 s 0.5 ) in the upper few centimeters, increasing with depth in a manner very similar to that of Earth’s Moon. Subsequent MIRO-based model predictions of the dayside surface temperatures reveal negative offsets of ∼5–30 K from the higher VIRTIS-measurements. By adding surface roughness in the form of 50% fractional coverage of hemispherical mini-craters to the MIRO-based thermal model, sufficient self-heating is produced to largely remove the offsets relative to the VIRTIS measurements and also reproduce the thermal limb brightening features (relative to a smooth surface model) seen by VIRTIS. The Lutetia physical property constraints provided by the VIRTIS and MIRO data sets demonstrate the unique diagnostic capabilities of combined infrared and submillimeter/millimeter thermal flux measurements.

Observations of the dayside of Venus performed by the high spectral resolution channel (–H) of the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board the ESA Venus Express mission have been used to measure the altitude of the cloud tops and the water vapor abundance around this level with a spatial resolution ranging from 100 to 10 km. CO2 and H2O bands between 2.48 and 2.60 μm are analyzed to determine the cloud top altitude and water vapor abundance near this level. At low latitudes (±40°) mean water vapor abundance is equal to 3 ± 1 ppm and the corresponding cloud top altitude at 2.5 μm is equal to 69.5 ± 2 km. Poleward from middle latitudes the cloud top altitude gradually decreases down to 64 km, while the average H2O abundance reaches its maximum of 5 ppm at 80° of latitude with a large scatter from 1 to 15 ppm. The calculated mass percentage of the sulfuric acid solution in cloud droplets of mode 2 (∼1 μm) particles is in the range 75–83%, being in even more narrow interval of 80–83% in low latitudes. No systematic correlation of the dark UV markings with the cloud top altitude or water vapor has been observed.

The condensing CO2 south polar cap of Mars and the mechanisms of the CO2 ice accumulation have been studied through the analysis of spectra acquired by the Planetary Fourier Spectrometer (PFS) during the first two years of ESA's Mars Express (MEX) mission. This dataset spans more than half a martian year, from Ls ∼ 330 ° to Ls ∼ 194 °, and includes the southern fall season which is found to be extremely important for the study of the residual south polar cap asymmetry. The cap expands symmetrically and with constant speed during the fall season. The maximum extension occurs sometime in the 80°-90° Ls range, when the cap edges are as low as -40° latitude. Inside Hellas and Argyre basins, frost can be stable at lower latitudes due to the higher pressure values, causing the seasonal cap to be asymmetric. Within the seasonal range considered in this paper, the cap edge recession rate is approximately half the rate at which the cap edge expanded. The longitudinal asymmetries reduce during the cap retreat, and disappear around Ls ∼ 145 °. Two different mechanisms are responsible for CO2 ice accumulation during the fall season, especially in the 50°-70° Ls range. Here, CO2 condensation in the atmosphere, and thus precipitation, is allowed exclusively in the western hemisphere, and particularly in the longitudinal corridor of the perennial cap. In the eastern hemisphere, the cap consists mainly of CO2 frost deposits, as a consequence of direct vapor deposition. The differences in the nature of the surface ice deposits are the main cause for the residual south polar cap asymmetry. Results from selected PFS orbits have also been compared with the results provided by the martian general circulation model (GCM) of the Laboratoire de Météorologie dynamique (LMD) in Paris, with the aim of putting the observations in the context of the global circulation. This first attempt of cross-validation between PFS measurements and the LMD GCM on the one hand confirms the interpretation of the observations, and on the other hand shows that the climate modeling during the southern polar night on Mars is extremely sensitive to the dynamical forcing. © 2008 Elsevier Inc. All rights reserved.

We present the spatial distribution of air temperature on Venus' night side, as observed by the high spectral resolution channel of VIRTIS (Visible and Infrared Thermal Imaging Spectrometer), or VIRTIS-H, on board the ESA mission Venus Express. The present work extends the investigation of the average thermal fields in the northern hemisphere of Venus, by including the VIRTIS-H data. We show results in the pressure range of 100-4. mbar, which corresponds to the altitude range of 65-80. km. With these new retrievals, we are able to compare the thermal structure of the Venus' mesosphere in both hemispheres.The major thermal features reported in previous investigations, i.e. the cold collar at about 65-70°S latitude, 100. mbar pressure level, and the asymmetry between the evening and morning sides, are confirmed here. By comparing the temperatures retrieved by the VIRTIS spectrometer in the North and South we find that similarities exist between the two hemispheres. Solar thermal tides are clearly visible in the average temperature fields. To interpret the thermal tide signals (otherwise impossible without day site observations), we apply model simulations using the Venus global circulation model Venus GCM (Lebonnois, S., Hourdin, F., Forget, F., Eymet, V., Fournier, R. [2010b]. International Venus Conference, Aussois, 20-26 June 2010) of the Laboratoire de Météorologie Dynamique (LMD). We suggest that the signal detected at about 60-70° latitude and pressure of 100. mbar is a diurnal component, while those located at equatorial latitudes are semi-diurnal. Other tide-related features are clearly identified in the upper levels of the atmosphere. © 2011 Elsevier Inc.

Acknowledgments We thank the Italian Institute of Astrophysics INAF for the financial support within the project PRIN-INAF 2011. We are thankful to OMEGA team and ESA staff for scientific, operational and technical supports. The aim of this work is to extract the surface contribution in the martian visible/near-infrared spectra removing the atmospheric components by means of Principal Component Analysis (PCA) and target transformation (TT). The developed technique is suitable for separating spectral components in a data set large enough to enable an effective usage of statistical methods, in support to the more common approaches to remove the gaseous component. In this context, a key role is played by the estimation, from the spectral population, of the covariance matrix that describes the statistical correlation of the signal among different points in the spectrum. As a general rule, the covariance matrix becomes more and more meaningful increasing the size of initial population, justifying therefore the importance of sizable datasets. Data collected by imaging spectrometers, such as the OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) instrument on board the ESA mission Mars Express (MEx), are particularly suitable for this purpose since it includes in the same session of observation a large number of spectra with different content of aerosols, gases and mineralogy. The methodology presented in this work has been first validated using a simulated dataset of spectra to evaluate its accuracy. Then, it has been applied to the analysis of OMEGA sessions over Nili Fossae and Mawrth Vallis regions, which have been already widely studied because of the presence of hydrated minerals. These minerals are key components of the surface to investigate the presence of liquid water flowing on the martian surface in the Noachian period. Moreover, since a correction for the atmospheric aerosols (dust) component is also applied to these observations, the present work is able to completely remove the atmospheric contribution from the analysed spectra. Once the surface reflectance, free from atmospheric contributions, has been obtained, the Modified Gaussian Model (MGM) has been applied to spectra showing the hydrated phase. Silicates and iron-bearing hydrated minerals have been identified by means of the electronic transitions of Fe2+ between 0.8 and 1.2 μm, while at longer wavelengths the hydrated mineralogy is identified by overtones of the OH group. Surface reflectance spectra, as derived through the method discussed in this paper, clearly show a lower level of the atmospheric residuals in the 1.9 hydration band, thus resulting in a better match with the MGM deconvolution parameters found for the laboratory spectra of martian hydrated mineral analogues and allowing a deeper investigation of this spectral range.