Publications by authors named "Tanguy Bertrand"

Triton and Pluto are believed to share a common origin, both forming initially in the Kuiper Belt but Triton being later captured by Neptune. Both objects display similar sizes, densities, and atmospheric and surface ice composition, with the presence of volatile ices N, CH, and CO. Yet their appearance, including their surface albedo and ice distribution strongly differ.

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The Mars Sample Return mission intends to retrieve a sealed collection of rocks, regolith, and atmosphere sampled from Jezero Crater, Mars, by the NASA Perseverance rover mission. For all life-related research, it is necessary to evaluate water availability in the samples and on Mars. Within the first Martian year, Perseverance has acquired an estimated total mass of 355 g of rocks and regolith, and 38 μmoles of Martian atmospheric gas.

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The Perseverance rover is carrying out an original acoustic experiment on Mars: the SuperCam microphone records the spherical acoustic waves generated by laser sparks at distances from 2 m to more than 8 m. These N-shaped acoustic waves scatter from the multiple local heterogeneities of the turbulent atmosphere. Therefore, large and random fluctuations of sound travel time and intensity develop as the waves cross the medium.

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Article Synopsis
  • Perseverance's Mastcam-Z captures detailed stereo and multispectral images, offering a comprehensive view of the geology in Jezero crater on Mars.
  • The rocks depicted show features indicating they are of igneous or impactite origin, with minimal water alteration and include various mineral compositions like mafic silicates and olivine.
  • Additional imaging reveals important atmospheric conditions, including dust variations and unique interactions caused by dust devils and the Ingenuity helicopter, which aid in understanding Mars' environment and assist in rover operations.
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Article Synopsis
  • Before the Perseverance rover, Jezero crater's floor was theorized to have different origins, including lake-related or volcanic processes.
  • SuperCam's findings over the first 286 days indicated a volcanic terrain characterized by varying compositions, primarily basaltic, with higher levels of plagioclase in upper strata and richer pyroxene in lower strata.
  • The study identified the first Martian cumulate rock, highlighting its olivine-rich content and suggesting brief past watery conditions based on the presence of various alteration materials.
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Despite the importance of sand and dust to Mars geomorphology, weather, and exploration, the processes that move sand and that raise dust to maintain Mars' ubiquitous dust haze and to produce dust storms have not been well quantified in situ, with missions lacking either the necessary sensors or a sufficiently active aeolian environment. Perseverance rover's novel environmental sensors and Jezero crater's dusty environment remedy this. In Perseverance's first 216 sols, four convective vortices raised dust locally, while, on average, four passed the rover daily, over 25% of which were significantly dusty ("dust devils").

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The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system.

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Pluto is covered by numerous deposits of methane, either diluted in nitrogen or as methane-rich ice. Within the dark equatorial region of Cthulhu, bright frost containing methane is observed coating crater rims and walls as well as mountain tops, providing spectacular resemblance to terrestrial snow-capped mountain chains. However, the origin of these deposits remained enigmatic.

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The surface of Pluto is more geologically diverse and dynamic than had been expected, but the role of its tenuous atmosphere in shaping the landscape remains unclear. We describe observations from the New Horizons spacecraft of regularly spaced, linear ridges whose morphology, distribution, and orientation are consistent with being transverse dunes. These are located close to mountainous regions and are orthogonal to nearby wind streaks.

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Pluto has a variety of surface frosts and landforms as well as a complex atmosphere. There is ongoing geological activity related to the massive Sputnik Planitia glacier, mostly made of nitrogen (N) ice mixed with solid carbon monoxide and methane, covering the 4-kilometre-deep, 1,000-kilometre-wide basin of Sputnik Planitia near the anti-Charon point. The glacier has been suggested to arise from a source region connected to the deep interior, or from a sink collecting the volatiles released planetwide.

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