Degradation of beta-carotene under mineral thin sections during proton irradiation monitored in situ by Raman spectroscopy
Abstract
More than 3.5 billion years ago, the surface of Mars experienced habitable conditions compatible with the emergence and development of primitive microbial life. Consequently, in the absence of plate tectonics, ancient biosignatures dating back several billion years could still be present at the surface of the red planet. Nevertheless, Mars has been continuously exposed to UV radiation and solar and galactic cosmic rays, which may have degraded these putative biosignatures at the surface over time. The European Space Agency's ExoMars Rosalind Franklin mission, expected to land on Mars in 2030, is thus equipped with a drill to collect samples up to 2 m deep to increase the chances of detecting well preserved molecules. Here, based on previous models, we first estimate the dose delivered in the first meters of Mars regolith over (geological) time. We then describe experiments in which beta-carotene (a pigment commonly used by microorganisms) was irradiated using a 2.8 MeV proton beam and its degradation with increasing dose studied by Raman spectroscopy, using a unique device allowing in situ measurements to be carried out within the irradiation chamber. Specific sample preparation, consisting of placing a thin mineral layer on top of the pigment, was also developed to take into account the dose distribution profile within the sample. Finally, based on the dose estimated for Mars, we correlate the change in the Raman signal-to-noise ratio of beta-carotene to an equivalent depth and time on Mars.
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BibTeX
@article{foucher2026degradation,
title = {{Degradation of beta-carotene under mineral thin sections during proton irradiation monitored in situ by Raman spectroscopy}},
author = {Frédéric Foucher and Mickael Baqué and Aurélien Canizarès and Rebecca Martellotti and Jean-Pierre de Vera and Thierry Sauvage and Paul Sigot and Olivier Wendling and Aurélien Bellamy and William Hate and Frances Westall},
journal = {Icarus},
year = {2026},
month = oct,
doi = {10.1016/j.icarus.2025.116674},
url = {https://hal.science/hal-05803256v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Degradation of beta-carotene under mineral thin sections during proton irradiation monitored in situ by Raman spectroscopy
AU - Frédéric Foucher
AU - Mickael Baqué
AU - Aurélien Canizarès
AU - Rebecca Martellotti
AU - Jean-Pierre de Vera
AU - Thierry Sauvage
AU - Paul Sigot
AU - Olivier Wendling
AU - Aurélien Bellamy
AU - William Hate
AU - Frances Westall
PY - 2026
DA - 2026/10/16
JO - Icarus
DO - 10.1016/j.icarus.2025.116674
UR - https://hal.science/hal-05803256v1
AB - More than 3.5 billion years ago, the surface of Mars experienced habitable conditions compatible with the emergence and development of primitive microbial life. Consequently, in the absence of plate tectonics, ancient biosignatures dating back several billion years could still be present at the surface of the red planet. Nevertheless, Mars has been continuously exposed to UV radiation and solar and galactic cosmic rays, which may have degraded these putative biosignatures at the surface over time. The European Space Agency's ExoMars Rosalind Franklin mission, expected to land on Mars in 2030, is thus equipped with a drill to collect samples up to 2 m deep to increase the chances of detecting well preserved molecules. Here, based on previous models, we first estimate the dose delivered in the first meters of Mars regolith over (geological) time. We then describe experiments in which beta-carotene (a pigment commonly used by microorganisms) was irradiated using a 2.8 MeV proton beam and its degradation with increasing dose studied by Raman spectroscopy, using a unique device allowing in situ measurements to be carried out within the irradiation chamber. Specific sample preparation, consisting of placing a thin mineral layer on top of the pigment, was also developed to take into account the dose distribution profile within the sample. Finally, based on the dose estimated for Mars, we correlate the change in the Raman signal-to-noise ratio of beta-carotene to an equivalent depth and time on Mars.
SN - 0019-1035
SN - 1090-2643
ER -