That is an artist’s impression of a water-vapor geyser on Europa. Picture credit score: College of Cologne.
“The proof for water vapor plumes on Europa isn’t as robust as we first understood it,” stated Dr. Kurt Retherford, a researcher at Southwest Analysis Institute one of many authors of a 2014 paper initially making that assertion.
Within the new examine, Dr. Retherford and his colleague analyzed knowledge collected by the Area Telescope Imaging Spectrograph (HST/STIS) aboard the NASA/ESA Hubble Area Telescope in 1999 and between 2012 and 2020.
They centered on Europa’s Lyman-alpha emission, a particular wavelength of ultraviolet mild emitted and scattered by hydrogen atoms.
“One of many difficulties in deciphering the information again then was figuring out the place to position Europa inside its context,” Dr. Retherford stated.
“The best way Hubble works left some uncertainty by way of placement relative to the middle of the picture.”
“If Europa’s placement was off even simply by a pixel or two, it might have an effect on how the information will get interpreted.”
In consequence, what the researchers thought might be proof of a water vapor plume might additionally simply be statistical noise.
“Our reanalysis took our unique 99.9% confidence within the plumes’ existence and decreased it to lower than 90% confidence,” stated Dr. Lorenz Roth, a researcher at KTH Royal Institute of Know-how.
“That’s merely not sufficient proof to help the understanding of claims we made on the time.”
“The present dataset doesn’t rule out the potential for the water vapor plumes described within the 2014 paper, but it surely not gives concrete proof of them,” Dr. Retherford stated.
“The outline of the phenomena simply doesn’t maintain up the identical manner anymore.”
“The brand new knowledge have made us rethink the power of the earlier paper’s conclusion concerning water vapor plumes.”
“The latest evaluation additionally gives improved details about the impartial hydrogen atom part of Europa’s escaping ambiance, originating from its water ice floor.”
“We nonetheless hope to seek out water vapor plumes escaping from Europa.”
“Comparable water vapor plumes have been confirmed on Saturn’s moon Enceladus, and Europa’s neighbor Io, one other moon of Jupiter, has plumes of sulfur dioxide increasing out into house.”
The staff’s new paper was revealed Might 5 within the journal Astronomy & Astrophysics.
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L. Roth et al. 2026. Europa’s Lyman-α emissions from HST/STIS observations. A&A 709, A59; doi: 10.1051/0004-6361/202659406
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