Observation of water vapor in the atmosphere of Ganymede, the largest moon in the solar system

for the first time, Astronomy scientists Discover water vapor inAtmosphere Ganymede, one of the four moons of Jupiter in Galilee. This discovery reinforces interest in this moon What we know today is It is home to an ocean of liquid salt water, sandwiched between two layers of ice at a depth of more than 160 kilometers below its surface. As in Europe and Callisto, two more moons of Jupiter.

This discovery owes to a team of astronomers under the supervision of Lorenz Ruth for you KTH . Royal Institute of Technology From Stockholm, Sweden, who are excavating ancient data fromHubble In order to prepare notes Juno’s missionThis amazing discovery. In fact, as emphasized Press release from ESA and NASA, « Where there is water, there can be life as we know it However, if this condition is necessary for the existence of a form of life, however simple it may be, it is clearly not sufficient. You also need a source of energy and essential elements ( Carbon majority ‘hydrogen Solve ‘azot N, l’Oxygen subordinate phosphorous P and matchsticks S) grouped under the acronym CHNOPS.

Raw data misinterpreted

By comparing the spectra made by the Hubble Stis instrument inultraviolet In 1998 and 2010, with further observations made in 2018 using the COS instrument to measure the amount of atomic oxygen in Ganymede’s atmosphere, astronomers realized that the initial data had been misinterpreted. While it was assumed from 1998 observations that there is atomic oxygen in the atmosphere Ganymede, astronomers came to the conclusion that, in the end, there was not much, unlike molecular oxygen, found in Ganymede’s atmosphere.

To explain this discovery, Lorenz Luth’s team observed that Ganymede’s surface temperature varies greatly throughout the day, and around noon, nearequator, can become hot enough to release small amounts of it to the surface of the ice molecules from water. In fact, the observed differences between the ultraviolet images, obtained at different times (from 1998, 2010 and 2018), are directly related to where water is expected to be in the lunar atmosphere. ” At first, only O₂ has been observedLorenz Roth explained. This occurs when charged particles erode the surface of the ice. The water vapor we have now measured comes from ice sublimation caused by thermal vapor leakage from H₂Hot icy regions. »

Jupiter’s moons are believed to be home to deep habitats

This discovery enhances the attraction mission juice The European Space Agency, whose mission is in particular to monitor Ganymede. Launched in 2022, juice It will reach Jupiter in 2029. It will work for at least three years to observe Jupiter and conduct in-depth studies of three of its largest frozen moons (Europe, Ganymede and Callisto) which are now known to host inner oceans. ” The juice will be of paramount importance in determining the habitability of planets with potentially oceans outside our own. ”, confirmed Gunther Hasinger, Director of Scientific Programs at the European Space Agency. If the schedule goes as planned, the mission is expected to end in June 2033.

As a result, Lorenz Roth’s team results can ” Providing juice teams with accurate information that can be used to improve monitoring plans to improve juice utilization ».