Publications by authors named "A Guilbert-Lepoutre"

Article Synopsis
  • - Charon, Pluto's largest moon, has been studied for its composition and changes caused by radiation, but previous spectral data only covered wavelengths below 2.5 μm, leaving some questions unanswered.
  • - Recent observations using JWST have detected carbon dioxide (CO) and hydrogen peroxide (HO) on Charon's northern hemisphere, adding to its known chemical components like water ice and ammonia.
  • - The presence of HO suggests active processes affecting the water ice surface, while spectral analysis indicates that CO is mainly found in crystalline form, likely originating from subsurface sources and other processes involving hydrocarbons and solar interactions.
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Article Synopsis
  • The Comet Interceptor mission aims to explore a long-period comet or an interstellar object entering our Solar System, with a focus on its surface composition, shape, and the composition of its gas and dust.
  • Proposed to the European Space Agency in 2018 and approved in June 2022, it is set to launch in 2029 alongside the Ariel mission, utilizing a low-cost approach that allows it to wait for a suitable target comet.
  • The mission will feature a main probe and two sub-probes (B1 from JAXA and B2), providing simultaneous, detailed 3D information about the comet and its interaction with the solar wind, making it unique compared to previous missions.
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We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of the mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft and a way to directly compare 67P with other comets.

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Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds. The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe.

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Pits have been observed on many cometary nuclei mapped by spacecraft. It has been argued that cometary pits are a signature of endogenic activity, rather than impact craters such as those on planetary and asteroid surfaces. Impact experiments and models cannot reproduce the shapes of most of the observed cometary pits, and the predicted collision rates imply that few of the pits are related to impacts.

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