The study of two potential plume sites on Jupiter's moon Europa has shown a lack of expected hotspot signatures, unlike Enceladus where plumes have a very clear and obvious temperature signature, research by Planetary Science Institute Senior Scientist Julie Rathbun shows.
"We searched through the available Galileo thermal data at the locations proposed as the sites of potential plumes. Reanalysis of temperature data from the Galileo mission does not show anything special in the locations where plumes have possibly been observed. There are no hotspot signatures at either of the sites," Rathbun said. "This is surprising because the Enceladus plumes have a clear thermal signature at their site of origin, so this suggests that either the Europa plumes are very different, or the plumes are only occasional, or that they don't exist, or that their thermal signature is too small to have been detected by current data."
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Europa volcanism & interior heating modeled in detail, offers research targets for upcoming missions
Europa, an icy Jovian moon that likely possesses an ocean beneath its icy crust, may have an interior that is hot enough to produce volcanic activity on its seafloor. New research provides evidence that this seafloor volcanism likely occurred in the moon's past and [may be] ongoing at present as well.
The team of researchers, led by Dr. Marie Běhounková of Charles University in the Czech Republic, developed their own 3D models of Europa's interior and heating transfer properties to investigate the possibility of volcanism on Europa's ocean floor given other volcanism seen in the Jovian system.
[...] These volcanoes would form due to the melting of Europa's interior and heat transfer from the rocky interior of Europa to the seafloor. Models developed by Běhounková et al. show that many different factors — including radiogenic power and tidal forces — contribute to the melting of the icy moon's interior.
[...] A Laplace resonance is a phenomenon that occurs when three planetary bodies with an orbital period ratio of 1:2:4 exert regular and periodic gravitational effects on each other. These nudges create tidal forces that translate to the heating of the body's interior.
It's that interaction that led Běhounková et al.'s research toward the conclusion that this resonance and the associate tidal forces can cause increased periods of volcanic activity — called magmatic pulses — on Europa.
Journal Reference:
Marie Běhounková, Gabriel Tobie, Gaël Choblet, et al. Tidally Induced Magmatic Pulses on the Oceanic Floor of Jupiter's Moon Europa, Geophysical Research Letters (DOI: 10.1029/2020GL090077)
Previously: Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Plate Tectonics on Europa and Subsurface Oceans in the Outer Solar System
NASA Finds Evidence of Water Plume on Europa
Europa Plume Sites Lack Expected Heat Signatures
Jupiter's Watery Moon, Europa, Is Covered in Table Salt
Jupiter's Ocean Moon Europa Probably Glows in the Dark
(Score: 5, Informative) by takyon on Wednesday October 24 2018, @03:46PM
NASA Finds Evidence of Water Plume on Europa [soylentnews.org]
The first evidence for Europa plumes came from Hubble rather than Galileo. As far as I can tell, the instruments on Cassini are somewhat more advanced than those on Galileo (compare Galileo's [wikipedia.org] Solid State Imager with Cassini's [wikipedia.org] Imaging Science Subsystem, for example). Jupiter Icy Moons Explorer will flyby Europa a couple of times, but more intensive observation of Europa would be done by Europa Clipper [wikipedia.org]. That mission doesn't have a firm launch date and has been tied up with the Space Launch System by Congress.
The ice shell on Enceladus is less thick [soylentnews.org] than that of Europa, which could be a result of Enceladus's smaller size (252 km radius vs. 1,561 km for Europa). That could help explain why the heat signatures on Europa don't correlate with plume sites, and why Europa doesn't appear to emit as many plumes.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]