Juno observations of Jupiter's moons
Abstract
NASA's Juno mission has been observing the Jupiter system since 2016 from a polar, highly elliptical orbit. Although not in the main scientific objectives, Juno took images and spectra of the Galilean moons from a very favourable position, using some of the cameras on board: JIRAM, JunoCam and SRU. JIRAM (Jovian Infrared Auroral Mapper) is a dual-band imager and spectrometer. The imager channel is a single detector with 2D capability and with 2 different filters (L band, from 3.3 to 3.6 µm; M band, from 4.5 to 5 µm); the spectrometer is a 1-D detector with a spectral resolution of 9 nm in the range 2 - 5 µm. The pixel angular resolution (0.01°) is fine enough for imaging the moons from the polar, highly elliptical orbit of Juno; the spatial resolution at the surface of the moons varies along the s/c distance and is of the order of 100 km/pixel or even finer. Here we present JIRAM's images and spectra of Io, Europa, and Ganymede after three years of Juno mission, together with JunoCam (the visible-light camera on Juno) and SRU (Stellar Reference Unit) images of Io. On Io, these observations characterize the location and possible morphology, and some temperatures, of the volcanic thermal sources; the identification of SO2, the possible identification of CO2and other materials. On Europa, they characterise the surface composition, grain size distribution and temperature, and the identification of both amorphous and crystalline ice phases and non-ice materials. On Ganymede, we study the depth of the ~2 μm water band to infer the regions where plasma precipitation acts as gardening for surface regolith.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P42A..07M
- Keywords:
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- 5706 Aurorae;
- PLANETARY SCIENCES: FLUID PLANETS;
- 5714 Gravitational fields;
- PLANETARY SCIENCES: FLUID PLANETS;
- 5724 Interiors;
- PLANETARY SCIENCES: FLUID PLANETS;
- 6220 Jupiter;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS