Oxygen and water vapor: This is what Lorenz Roth of the Royal Swedish Institute of Technology has identified in Europe’s atmosphere, one of Jupiter’s 79 moons. details.
The astrophysicist used images taken between 1999 and 2015 by the Hubble Space Telescope. Two typical light emissions of an oxygen atom were detected there: their relative intensity indicates that this oxygen sometimes belongs to a molecule of gaseous oxygen dioxide (O2), and sometimes to water (H2O). “The models predicted the presence of Water vapor, because Europe is covered with ice, Explains François Leblanc, of Atmospheres, Environments and the Laboratory of Spatial Observations (Latmos). But the originality of this work is that it shows that this atmosphere is severely asymmetric. “
Like our moon, Europa always presents the same face (called the “front face”) in the direction of its rotation. However, water vapor was only detected above the back face! Reason ? This face is bombarded even more by particles from the magnetosphere that are rapidly orbiting Jupiter, the region where the planet’s magnetic field is spread. Opaque due to these effects, the surface of the far side of Europa absorbs more energy. Its temperature rises, which helps the ice sublimate into steam.
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