A good news has now come from the outer world. Astronomers for the first Time have uncovered evidence of water vapour in the atmosphere of Jupiter’s moon Ganymede. The water vapour is believed to form when ice from the moon’s surface sublimates.
The researchers used the latest and archival datasets from NASA’s Hubble Space Telescope. They published the findings in the journal Nature Astronomy. Earlier findings showed circumstantial evidence that Ganymede contained more water than all of Earth’s oceans. The researchers had said that Ganymede’s ocean would reside roughly 100 miles below the crust. As such the water vapour would not represent the evaporation of this ocean, the researchers maintained.
As part of a larger program to support NASA’s Juno mission in 2018 Lorenz Roth of the KTH Royal Institute of Technology in Stockholm Sweden led the team that set out to measure the amount of atomic oxygen with Hubble. They analysised data from two instruments – Hubble’s Cosmic Origins Spectrograph in 2018 and archival images from the Space Telescope Imaging Spectrograph (STIS) from 1998 to 2010. Contrary to the earlier data interpretations, the researchers found that there was hardly any atomic oxygen in Ganymede’s atmosphere. They thought of another explanation for the apparent differences in these UV aurora images. They found that the surface temperature of Ganymede varied strongly throughout the day, and around noon near the equator it may become sufficiently warm that the ice surface releases Small amounts of water molecules. They concluded that the perceived differences in the UV images are directly correlated with where we would be expected in the moon’s atmosphere.
On the research, Roth pointed said only the molecular oxygen had been observed. The scientist explained that this was produced when charged particles erode the ice surface. “The water vapour that we measured originates from ice sublimation caused by the thermal scope of water vapour from warm icy regions,” Roth said.
ESA JUICE MISSION
NASA pointed out that the finding added to the anticipation to Europe Space Agency’s upcoming mission, JUICE. The mission is the first large class one in ESA’s Cosmic Vision 2015-2025 program. Planned for lunch 2022 and arrival at Jupiter in 2029, JUpiter ICy moons Explorer will spend at least three years making detailed observations of Jupiter and three its largest moons, with particular emphasis on Ganymede as a planetary boy and potential habitat.
Roth said their findings could provide the JUICE instrument teams with valuable information that may be used to refine their observation plans to optimize the use of the spacecraft.