The Hubble Space Telescope has long hinted at sulphur dioxide ice on Callisto. Credit: NASA/JPL/DLR
Callisto, one of Jupiter's moons, may have ozone, researchers say after successfully simulating its icy surface conditions in a lab1.
Ozone absorbs the Sun’s harmful ultraviolet radiation, aiding the formation of important molecules such as amino acids essential for life, says an international research team.
The Hubble Space Telescope has long hinted at sulphur dioxide ice on Callisto. To find whether its surface traps ozone, scientists mimicked the icy environment of Callisto by keeping sulphur dioxide ice in a vacuum chamber at an extremely low temperature. They then bombarded it with vacuum ultraviolet photons for four hours in a lab at the National Synchrotron Radiation Research Center in Taiwan.
The team, including researchers at the Physical Research Laboratory in Ahmedabad and the Institute of Astronomy, Space and Earth Science in Kolkata, found that irradiation broke down sulphur dioxide molecules and liberated oxygen atoms. The oxygen atoms then formed oxygen molecules. Once enough oxygen molecules formed within the ice, they added an oxygen atom to a molecule to yield an ozone molecule.
Spectral analysis of the irradiated ice, supported by latest Hubble Space Telescope data, provided compelling evidence for the presence of ozone on Callisto.
The researchers say the Jupiter Icy Moons Explorer, the interplanetary spacecraft currently headed towards Jupiter, could corroborate these findings further.
