Fluorescent Biomolecules Detectable in Near-Surface Ice on Europa
Europa, Jupiter’s second Galilean moon, is believed to host a subsurface ocean in contact with a rocky mantle, where hydrothermal activity may drive the synthesis of organic molecules.
Of these molecules, abiotic synthesis of aromatic amino acids is unlikely, and their detection on Europa could be considered a biosignature. Fluorescence from aromatic amino acids, with characteristic emissions in the 200-400 nanometer wavelength range, can be induced by a laser and may be detectable where ocean material has been relatively recently emplaced on Europa’s surface, as indicated by geologically young terrain and surface features.
However, surface bombardment by charged particles from the Jovian magnetosphere and solar ultraviolet (UV) radiation degrades organic molecules, limiting their longevity. We model radiolysis and photolysis of aromatic amino acids embedded in ice, showing dependencies on hemispheric and latitudinal patterns of charged particle bombardment and ice phase.
We demonstrate that biosignatures contained within freshly deposited ice in high-latitude regions on the surface of Europa are detectable using laser-induced UV fluorescence, even from an orbiting spacecraft.
Effectiveness of distinct degradation mechanisms on Europa, plotted over images of Europa’s leading and trailing hemispheres taken by the Galileo spacecraft. (a) and (b) Relative amino acid concentrations at select locations on the leading and trailing hemispheres, respectively, after being subjected to each distinct and independent degradation mechanism for 106 years. Dashed lines: photolysis at select latitudes (colors). Solid lines: radiolysis by electrons at select latitudes (colors). Dotted orange line: radiolysis by ions, which is assumed to be uniform across Europa’s surface. (c) and (d) Most effective degradation mechanism at different locations of the trailing and leading hemispheres, respectively, after 106 years, assuming a radiolytic constant of 0.034 MGy−1 . Photolysis is not shown as it is not the dominant degradation mechanism anywhere on Europa’s surface. — astro-ph.EP
Gideon Yoffe, Keren Duer, Tom Andre Nordheim, Itay Halevy, Yohai Kaspi
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2503.06971 [astro-ph.EP] (or arXiv:2503.06971v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2503.06971
Focus to learn more
Submission history
From: Gideon Yoffe
[v1] Mon, 10 Mar 2025 06:37:12 UTC (25,035 KB)
https://arxiv.org/abs/2503.06971
Astrobiology, Astrochemistry,
