With the help of Hubble’s Space Telescope, a team of astronomers recently spotted a corona of atomic hydrogen surrounding the icy moon of Jupiter, the Europa. The discovery holds a key place with the respect to better understanding of tenuous atmosphere of Jupiter’s moon. Europa has a very thin layer of atmosphere that consists of molecular oxygen that is produced through radiolysis and sputtering of moon’s surface ice when it gets influenced with ions of magnetosphere. While oxygen happens to be one of the densest component that constitutes Europa’s atmosphere, the sputtering over this surface also leads to generation of molecular hydrogen at the same rate as of molecular oxygen.
Nevertheless, it is known that it is only the noncondensable molecular oxygen that creates a near-surface bound atmosphere, meanwhile other products like water either freeze over the surface or quickly move out of the moon’s gravity.
The team working on this project is being led by Lorenz Roth from KTH Royal’s Institute of Technology located in Stockholm Sweden. In order to get a better insight the features of this atmosphere, the team further observed the moon under UV rays with the very same telescope. However, as most of the UV light gets absorbed in atmosphere like this, it is not possible to make such observation from a ground based telescope and need something like the HST. The far-UV observational campaign using HST permitted the team to get close images of Europa while six transits of Jupiter were taking place. These observations were mainly focused on detecting of signs of water vapor’s presence.
Lorenz adds, “The main goal of the observing campaign was actually finding localized signals from water vapor in the ultraviolet hydrogen emission. Ye we found a widely extended and homogeneous cloud of hydrogen around Europa.”
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