- The last talk in the Satellite Atmospheres session this past Thursday, September 17, was titled, "First detection of Io's atmosphere at 4.0 micron" and was presented by Emmanuel Lellouch et al. Lellouch and his colleagues observed Io in the near-infrared using the CRIRES spectrometer at the Very Large Telescope in Chile in July 2008. These measurements allowed the authors to observe an absorption band of sulfur dioxide gas at 4.0 μm. With the adaptive optics system at VLT, they were also able to spatial resolve variations in the absorption band, looking for differences in atmospheric column density between the polar region and the equator. Lellouch et al. believe that these observation open up a new avenue for monitoring Io's dynamic atmosphere.
- The Satellite Surfaces and Interiors oral session this past Wednesday, September 16 hosted two Io talks. The first was titled, "Volcanism on Io: New Insights from Global Geologic Mapping" and was presented by David Williams et al. This talk and abstract provide an update to the Io geologic mapping project, a subject Williams presented at this year's Lunar and Planetary Sciences Conference, which I discussed in greater depth earlier this year. This geologic map displays the distribution of various morphologic and color units across Io's surface. Using software such as ArcGIS™ will allow researchers to use the map to conduct various lines of research, including comparing the areas of various mountain units with their heights, looking at the areal extent of the various plains units, and seeing how ongoing volcanism change these areal extent of the different lava flow units. The authors also plan to assess the distribution of different flow units to assess regional variations in the style of volcanism (sulfur versus silicate volcanism, for example) and compare these units to observed volcanic hotspots to look for correlations between eruption style and unit types. The Io Geologic map was completed in February 2009 and has been submitted to the USGS for peer review. A similar global geologic map of Ganymede was also presented at the conference, which has garnered some press coverage (but not Io's, bah I say, BAH!) .
- The other Io talk at the Surfaces session was titled, "Continued Observations of Io's Volcanic Activity" and was presented by Imke de Pater et al. In this abstract, de Pater briefly presents new results from observations of Io in the near-infrared using the adaptive optics system at Keck in Hawaii. These results include new observations of volcanic hot spots on Io as well as the distribution of sulfur dioxide frost across Io's surface. While the abstract left out specifics, the authors spent more time advocating for additional telescopic observations of Io. Regular observation runs were conducted during the Galileo mission and the New Horizons flyby in 2007, but outside of that flyby, Io monitoring has been sparse the last few years. Regular monitoring is important for understanding Io's heat flow and its active volcanism. de Pater et al. also advocate for the inclusion of narrow angle cameras on board Jupiter-bound missions, particularly EJSM, to provide for monitoring of Io and other satellites in the system.
- Finally, Ashley Davies, Laszlo Keszthelyi, and Alfred McEwen presented a poster titled, "Determining Io Lava Eruption Temperature: Strategies for a New Mission to the Solar System's Most Dynamic Satellite." These authors presented a similar poster at LPSC earlier this year, which was discussed here a bit more extensively. This abstract discusses how the desire to measure the temperature of Ionian lava using near-infrared camera observations of lava fountains and skylights (holes in the roofs of lava tubes). The authors explain that near-simultaneous, high-resolution color imaging during Io flybys by either a dedicated Io mission (such as the Io Volcano Observer) or by another Jupiter system mission (like EJSM) would be necessary for determining these lava temperatures without the issues from short-term variability (on the order of a few seconds) of lava fountains. The authors also state that these observations would need to be preformed over Io's night-side to avoid contamination from sunlight.
Link: European Planetary Science Congress [meetings.copernicus.org]