| Title: |
Mapping of the Ganymede surface reflectance from Juno/UVS data |
| Authors: |
Benmahi, Bilal; Hue, Vincent; Molyneux, Philippa; Vorburger, Audrey; Waite, Jack, H; Gronoff, Guillaume; Bouquet, Alexis; Gladstone, Randy; Leblanc, François; Benne, Benjamin; Bonfond, Bertrand; Barthelemy, Mathieu; Blanc, Michel; Grodent, Denis, C; Greathouse, Thomas, K |
| Contributors: |
Laboratoire d'Astrophysique de Marseille (LAM); Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS); Laboratoire de Physique Atmosphérique et Planétaire (LPAP); Université de Liège = University of Liège = Universiteit van Luik = Universität Lüttich (ULiège); Space Science and Engineering Division San Antonio; Southwest Research Institute San Antonio (SwRI); Space Research and Planetary Sciences Bern) (WP); Physikalisches Institut Bern; Universität Bern = University of Bern = Université de Berne (UNIBE)-Universität Bern = University of Bern = Université de Berne (UNIBE); Department of Physics and Astronomy Tuscaloosa); University of Alabama Tuscaloosa (UA); NASA Langley Research Center Hampton (LaRC); Science Systems and Applications, Inc. Hampton (SSAI); Physique des interactions ioniques et moléculaires (PIIM); Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS); Department of Climate and Space Sciences and Engineering (CLaSP); Université du Michigan = University of Michigan Ann Arbor (UMich); SYSTEME SOLAIRE - LATMOS; Laboratoire Atmosphères, Observations Spatiales (LATMOS); Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS); School of Geosciences Edinburgh; The University of Edinburgh; Centre for Exoplanet Science; Institut de Planétologie et d'Astrophysique de Grenoble (IPAG); Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG)-Université Grenoble Alpes (UGA); Centre Spatial Universitaire de Grenoble (CSUG); Institut de recherche en astrophysique et planétologie (IRAP); Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulouse (EPE UT); Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse) |
| Source: |
ISSN: 0004-6361. |
| Publisher Information: |
CCSD; EDP Sciences |
| Publication Year: |
2026 |
| Collection: |
Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ |
| Subject Terms: |
gaseous planets; aurorae; planets and satellites: atmospheres; plasmas; radiative transfer; [SDU]Sciences of the Universe [physics] |
| Description: |
International audience ; Ganymede is the only moon in the Solar System with an intrinsic magnetic field that actively interacts with the Jupiter magnetosphere. This precipitates energetic electrons that generate ultraviolet (UV) auroral emission. Aims. In sunlit auroral regions, the observed emission partly overlaps with the solar continuum reflected by the surface. An accurate modeling of the observed UV spectra therefore requires precise knowledge of the surface spectral reflectance. Methods. We analyzed Juno/UVS data acquired during the 34th perijove (PJ) flyby to constrain the Ganymede surface reflectance in the 140-205 nm range. We used the non-local thermal equilibrium radiative transfer model originally developed to simulate the auroral emission of Ganymede, which also accounts for the reflection of solar flux by the satellite surface, to fit the observed spectra in sunlit auroral regions. Results. Our results revealed that the reflectance varies strongly spatially and spectrally from 0.1% to 8% in the [140 nm; 205 nm] wavelength range. This indicates a significant surface heterogeneity. This variability likely reflects long-term interactions between the icy surface of Ganymede and precipitating energetic particles, which alter the ice structure and crystallinity and its chemical composition. In addition, the derived reflectance maps show no clear correlation with the visible surface features of Ganymede, suggesting that the UV reflectance is primarily shaped by irradiation-driven processes and not by the geological morphology. Conclusions. The resulting reflectance maps provide a critical input for future UV auroral emission modeling, particularly in preparation for observations by the Juice/UVS mission. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1051/0004-6361/202557459 |
| Availability: |
https://hal.science/hal-05528391; https://hal.science/hal-05528391v1/document; https://hal.science/hal-05528391v1/file/aa57459-25.pdf; https://doi.org/10.1051/0004-6361/202557459 |
| Rights: |
https://creativecommons.org/licenses/by/4.0/ ; info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.2CE5B6A6 |
| Database: |
BASE |