They could have detected water vapor in Ganymede’s atmosphere

Observations were made for 20 years by a space telescope Hubble Indicates the presence of water vapor in the atmosphere of Ganymede, the icy moon of Jupiter. The findings make the icy moon an even more interesting target in the search for extraterrestrial life.

The apparent discovery of water vapor came after researchers compared two Ganymede observations in 1998 with another round of observations made in 2018. One analysis identified sublime water in the atmosphere as the most likely cause of the discrepancy in the 1998 data. The team that made the 2018 observations Its results have been published in natural astronomy.

In 1998, the Space Telescope Imaging Spectrum (STISHubble took two ultraviolet images of Ganymede, which revealed bands in the moon’s atmosphere that resemble the aurora borealis, which means the moon has a permanent magnetic field. There were slight differences in Hubble’s ultraviolet observations at that time, which are attributed to the presence of atomic oxygen in the atmosphere.

These observations were followed up in 2018 by ultraviolet observations of Ganymede using cosmic origins spectrometer From Hubble, which sought to measure the amount of atomic oxygen in the atmosphere and compare it with previous data, both 1998 and 2010. But the new team of researchers found almost no atomic oxygen in Ganymede’s atmosphere, suggesting that earlier ultraviolet images showed something What else.

The team found the answer in how Ganymede’s aurora is distributed in two 1998 images. Over the course of a day at Ganymede, its surface temperature rises and falls. When it’s noon on the moon, the surface can heat up enough to release water molecules.

Lorenz Roth, lead author of the study and a planetary astronomer at KTH Royal Institute of Technology in Sweden, wrote in a recent blog post “behind the paperFor nature, the difference in the images is exactly where you would expect water in the atmosphere. And water vapor has a similar effect to atomic oxygen on the spectral signal…”In other words, what appears to be a discrepancy in atomic oxygen could be water vapor that appears in one image without the other. Because of the regions of the atmosphere they were targeting.

in a release Roth added that the upcoming Jupiter Icy Moons Explorer mission (JUICE) could incorporate the latest discovery into its investigations of Ganymede’s other icy moons, Europa and Callisto. In fact, Europe is believed to have water columns That launch from an underground ocean and a spacecraft It could have flown Through one of these pillars in 1997. Ganymede’s water vapor makes these worlds more interesting For astrobiologists.