Icarus最新文献

{"title":"Mie theory-based light scattering analysis of entrained grains in Io's Tvashtar plume observed during new horizons' 2007 flyby","authors":"A.O. Adeloye ,&nbsp;L.M. Trafton ,&nbsp;D.B. Goldstein ,&nbsp;P.L. Varghese ,&nbsp;A. Mahieux","doi":"10.1016/j.icarus.2025.116628","DOIUrl":"10.1016/j.icarus.2025.116628","url":null,"abstract":"<div><div>Io, the most volcanically active body in the Solar System, frequently produces large-scale plumes capable of reaching hundreds of kilometers in height. During the 2007 New Horizons (NH) flyby, the Tvashtar Catena region exhibited a ∼ 350 km high “Pele-type” plume whose canopy radiance in scattered sunlight increased unexpectedly by an order of magnitude over 3–4 days. This radiance surge occurred as the solar phase angle between the Sun, Io, and NH rose from ∼40° to 150°, suggesting that observational geometry could play a key role; earlier investigations found that changes in basic volcanic vent parameters, such as stagnation temperature and vent area, did not fully explain this irregular brightness increase (Adeloye et al., 2025).</div><div>In this study, we utilize Mie theory to characterize light scattering and integrate multiple lines of analysis to identify the primary factors influencing Tvashtar's plume radiance. We employ Direct Simulation Monte Carlo (DSMC) modeling to simulate SO₂ gas dynamics and entrained basaltic grains, assuming a log-normal grain size distribution. Additionally, we examine multiple factors that could potentially contribute to the observed phenomena, including variations in the NH observation geometry, the scattering properties of individual and ensembles of grains, and vent parameters such as mass flow rate and grain mass loading.</div><div>Our results indicate that no single factor can fully account for the irregular brightness surge. Instead, a combination of observational geometry effects, the optical scattering behavior of the grains in the plume, and changes in grain mass loading are required to reproduce the observed radiance profile and its changes. Although our methodology assumes continuous, steady-state ejection over tens of minutes and does not explicitly model condensation, sublimation, or episodic grain injection at the vent, the integrated approach presented here offers a novel perspective on plume dynamics at Io. These findings not only enhance the interpretation of the NH Tvashtar observations but also provide a framework for future investigations of Io's volcanic plumes and potential exploration missions.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"438 ","pages":"Article 116628"},"PeriodicalIF":2.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implications of a highly convective lunar magma ocean: Insights from phase equilibria modeling","authors":"K.A. Cone ,&nbsp;S.M. Elardo ,&nbsp;F.J. Spera ,&nbsp;W.A. Bohrson ,&nbsp;R.M. Palin","doi":"10.1016/j.icarus.2025.116629","DOIUrl":"10.1016/j.icarus.2025.116629","url":null,"abstract":"<div><div>The Moon's internal structure was largely defined within the first 200 million years following the initial Moon-forming impact. During this period, the lunar magma ocean (LMO) lost most of its heat through early vigorous convection, crystallizing and forming an initial cumulate stratigraphy through, potentially, robust equilibrium crystallization followed by fractional crystallization once the LMO became sufficiently viscous. This rheological transition is estimated to have occurred at 50 % to 60 % LMO solidification, and although the petrological effects of the regime switch have been frequently investigated at the lower value, such effects at the upper limit have not been formally examined until now. Given this scenario, we present two new internally consistent, high-resolution models that simulate the solidification of a deep LMO of Earth-like bulk silicate composition at both rheological transition values, focusing on the petrological characteristics of the evolving mantle and crust. The results suggest that increasing the volume of early suspended solids from the oft-examined 50 % to 60 % may lead to non-trivial differences. The appearance of minor mantle garnet without the need to invoke a refractory-element enriched bulk silicate Moon composition, a bulk mantle relatively richer in orthopyroxene than olivine, a lower density upper mantle, and a thinner crust are shown to change systematically between the two models, favoring prolonged early crystal suspension. In addition, we show that late-stage, silica-enriched melts may not have sufficient density to permit plagioclase to continue building a floatation crust and that plagioclase likely sinks or stagnates. As the ability of a lunar magma ocean to suspend crystals is directly tied to the Moon's early thermal state, the degree of early LMO convection – and the immediate Solar System environment that drives it – require as much consideration in LMO models as more well-investigated parameters such as bulk silicate Moon composition and initial magma ocean depth.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"438 ","pages":"Article 116629"},"PeriodicalIF":2.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lunar impact ejecta flux on the Earth","authors":"Jose Daniel Castro-Cisneros ,&nbsp;Renu Malhotra ,&nbsp;Aaron J. Rosengren","doi":"10.1016/j.icarus.2025.116606","DOIUrl":"10.1016/j.icarus.2025.116606","url":null,"abstract":"<div><div>The transfer of material between planetary bodies due to impact events is important for understanding planetary evolution, meteoroid impact fluxes, the formation of near-Earth objects (NEOs), and even the provenance of volatile and organic materials at Earth. This study investigates the dynamics and fate of lunar ejecta reaching Earth. We employ the high-accuracy IAS15 integrator within the REBOUND package to track for 100,000 years the trajectories of 6,000 test particles launched from various lunar latitudes and longitudes. Our model incorporates a realistic velocity distribution for ejecta fragments (tens of meters in size), derived from large lunar cratering events. Our results show that 22.6% of lunar ejecta collide with Earth, following a power-law <span><math><mrow><mi>C</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow><mo>∝</mo><msup><mrow><mi>t</mi></mrow><mrow><mn>0</mn><mo>.</mo><mn>315</mn></mrow></msup></mrow></math></span>, with half of the impacts occurring within <span><math><mo>∼</mo></math></span>10,000 years. We also confirm that impact events on the Moon’s trailing hemisphere serve as a dominant source of Earth-bound ejecta, consistent with previous studies. Additionally, a small fraction of ejecta remains transiently in near-Earth space, providing evidence that lunar ejecta may contribute to the NEO population. This aligns with recent discoveries of Earth co-orbitals such as Kamoóalewa (469219, 2016 HO3) and 2024 PT5, both exhibiting spectral properties consistent with lunar material. These findings enhance our understanding of the lunar ejecta flux to Earth, providing insights into the spatial and temporal patterns of this flux and its broader influence on the near-Earth environment.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"438 ","pages":"Article 116606"},"PeriodicalIF":2.5,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New astrometric positions of Neptune and Triton in 2020–2024","authors":"D. Yan ,&nbsp;R.C. Qiao ,&nbsp;H.Y. Zhang ,&nbsp;Y. Yu","doi":"10.1016/j.icarus.2025.116625","DOIUrl":"10.1016/j.icarus.2025.116625","url":null,"abstract":"<div><div>A total of 3836 astrometric positions of Neptune and its largest irregular satellite Triton were obtained in the period 2020–2024 by the 1.0 m telescopes at Yunnan Astronomical Observatory. Based on Gaia DR3 catalogue and the six-parameter plate model, 1918 new positions of Neptune and 1918 new positions of Triton were collected. For the observations of Neptune, with the comparison of DE441, the mean residuals are 30 mas and − 27 mas in right ascension and declination, the standard deviation of residuals are 28 mas and 33 mas in right ascension and declination. For the observations of Triton, with the comparison of the theoretical positions derived from <span><span>Jacobson (2009)</span></span> satellite orbit model and DE441, the mean residuals are 7 mas and − 14 mas in right ascension and declination, the standard deviation of residuals are 29 mas and 31 mas in right ascension and declination. Moreover, we also compared three recent orbit models of triton as well as three different planetary ephemerides of Neptune. These comparisons show that the differences among all the three planetary ephemerides are obvious.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116625"},"PeriodicalIF":2.5,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preservation and detection of carotenoid pigments of Deinococcus radiodurans on mineral substrates under UV irradiation","authors":"Tamires Gallo ,&nbsp;Fabio Rodrigues ,&nbsp;Evelyn A.M. Sanchez ,&nbsp;Fabio S. de Vicente ,&nbsp;Veronica C. Teixeira ,&nbsp;Evandro P. Silva ,&nbsp;Marcia Rizzuto ,&nbsp;Gabriel S. Teofilo-Guedes ,&nbsp;Douglas Galante","doi":"10.1016/j.icarus.2025.116624","DOIUrl":"10.1016/j.icarus.2025.116624","url":null,"abstract":"<div><div>Biosignatures (or biomarkers), such as carotenoids, derived from microorganisms serve as valuable indicators of past or present life within the geological record on planetary surfaces. This study investigates the resistance and preservation of carotenoid pigments from the poly-extremophilic bacterium <em>Deinococcus radiodurans</em> across various mineral substrates using Raman spectroscopy and diffuse reflectance in the UV–Vis range. Pigment-substrate mixtures were exposed to simulated conditions mimicking the surface of Mars, a UV-rich terrestrial environment, and space conditions at the Toroidal Grating Monochromator beamline of the Brazilian Synchrotron Light Laboratory. Our findings reveal that the topmost layers of the substrate act as protective shields against radiation, preserving biomolecules located a few hundred micrometers below the surface in all three simulated environments. This integrated approach offers a promising analysis protocol for an in situ search for molecular fossils on diverse planetary surfaces, eliminating the need for extensive sample preparation.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"438 ","pages":"Article 116624"},"PeriodicalIF":2.5,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemistry of benzene (C6H6) hydrogen cyanide (HCN) co-condensed ices part 2: Formation of aerosols analogues of titan's atmosphere","authors":"I. Couturier-Tamburelli,&nbsp;G. Danger,&nbsp;J. Mouzay,&nbsp;N. Piétri","doi":"10.1016/j.icarus.2025.116626","DOIUrl":"10.1016/j.icarus.2025.116626","url":null,"abstract":"<div><div>This experimental work has been carried out to characterize the nature of the aerosols analogues of Titan's atmosphere produced by the FUV irradiation of various C₆H₆:HCN co-condensed ices. Using infrared spectroscopy, in the spectral region probed by VIMS (Visual and Infrared Mapping Spectrometer), C₆H₆:HCN residues show some similarities with those of aerosols present in the Titan stratosphere. In addition, some spectral features in the range covered by the CIRS (Composite InfraRed Spectrometer) instrument support the greater similarity of C₆H₆:HCN residues with Titan's stratospheric haze than with the pure C₆H₆ residues. GC–MS (Gas Chromatography-Mass Spectrometry) analysis of the soluble fraction of C₆H₆-HCN residues shows that they are composed of polyphenyl aromatic rings and benzonitrile derivatives. These initial data allow us to probe the complexity of the residues produced by the photochemical aging process that co-condensed C₆H₆:HCN ices could undergo. They also provide a first overview into the structures that could be produced by these processes and which could be potentially detected on Titan‘s surface after sedimentation, during the future Dragonfly space mission.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"438 ","pages":"Article 116626"},"PeriodicalIF":2.5,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lunar volcanic gas cloud chemistry: Constraints from glass bead surface sublimates","authors":"T.A. Williams ,&nbsp;S.W. Parman ,&nbsp;A.E. Saal ,&nbsp;A.J. Akey ,&nbsp;J.A. Gardener ,&nbsp;R.C. Ogliore","doi":"10.1016/j.icarus.2025.116607","DOIUrl":"10.1016/j.icarus.2025.116607","url":null,"abstract":"<div><div>Lunar pyroclastic glass beads preserve a record of physical and chemical conditions within volcanic gas clouds in the form of nanoscale minerals vapour-deposited onto their surfaces. However, the scale of these mineral deposits - less than 100 nm - has presented challenges for detailed analysis. Using SEM, TEM, APT, and NanoSIMS, we analysed pristine black glass beads from Apollo drive tube 74001 and found a sequence of sulfide deposition that directly evidences lunar gas cloud evolution. The deposits are predominantly micromound structures of nanopolycrystalline sphalerite ((Zn,Fe)S), with iron enrichment at the bead-micromound interface. Thermochemical modelling indicates that hydrogen and sulfur were major elements within the volcanic plume and ties the iron gradient to decreasing gas pressure during deposition. This pressure drop may also be consistent with our observed trend of potential <span><math><msup><mi>δ</mi><mn>34</mn></msup><mi>S</mi></math></span> depletion. Finally, Apollo 17 74220 orange beads, deposited higher in the Shorty Crater sequence, appear to lack abundant ZnS nanocrystals (<span><span>Liu and Ma, 2024a</span></span>), suggesting a change in vapour deposition between orange- and black-glass bead deposition. Together, our results suggest a change in eruption style over the course of a pyroclastic volcanic eruption in the Taurus-Littrow Valley.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"438 ","pages":"Article 116607"},"PeriodicalIF":2.5,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the depth of the regolith around radar-dark halo craters on the Moon","authors":"A.D. Thaker ,&nbsp;C.D. Neish","doi":"10.1016/j.icarus.2025.116623","DOIUrl":"10.1016/j.icarus.2025.116623","url":null,"abstract":"<div><div>Impact cratering is a ubiquitous geological process in our Solar System and plays an important role in shaping the landscape of many planetary bodies, including the Moon. Our study focuses on the unique radar-dark halo craters (RDHCs) on the Moon, which are surrounded by distinctive, ring-shaped structures (i.e., haloes) that have unusually low radar backscatter. Our aim is to understand the interaction between the ejecta emplacement around RDHCs and the lunar regolith by assessing the local depths of the regolith surrounding RDHCs. We use the morphology of small impact craters (∼10–250 m) to infer the depth of the regolith around these RDHCs. We examine small craters in images from the Lunar Reconnaissance Orbiter's (LRO) Narrow Angle Camera (NAC) within the continuous and discontinuous ejecta blankets of five RDHCs. We then compare these results with those of five non-RDHCs. Overall, we observe similar regolith characteristics around RDHCs and non-RDHCs. Interestingly, our results do not show a strong correlation between crater age and regolith depths. This suggests that despite continued bombardment, the regolith layer is not getting significantly deeper with age. In addition to impact gardening, there may be other factors contributing to regolith formation around impact craters on the Moon. Additionally, our study suggests that the flat-floor small crater morphology is more dominant for the RDHCs than non-RDHCs, which points to a deeper and more uniform mixture of regolith in these regions. Our study thus suggests that the emplacement of fine-grained RDH material over bedrock disrupts the ordinary regolith formation. We conclude that a careful re-examination of our understanding of regolith formation and evolution is necessary.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116623"},"PeriodicalIF":2.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis of the olivine cumulate outcrop Issole – The missing link between the Séítah and Máaz formations in Jezero crater, Mars","authors":"Juan David Hernández-Montenegro ,&nbsp;Tanya V. Kizovski ,&nbsp;Allan H. Treiman ,&nbsp;An Y. Li ,&nbsp;Paul D. Asimow ,&nbsp;Mariek E. Schmidt ,&nbsp;Yang Liu ,&nbsp;Josh Labrie ,&nbsp;Abigail L. Knight ,&nbsp;Michael M. Tice ,&nbsp;David A. Klevang ,&nbsp;Scott VanBommel ,&nbsp;Lawrence A. Wade ,&nbsp;Joel A. Hurowitz ,&nbsp;Adrian J. Brown ,&nbsp;Morgan L. Cable ,&nbsp;Abigail C. Allwood ,&nbsp;the PIXL team","doi":"10.1016/j.icarus.2025.116620","DOIUrl":"10.1016/j.icarus.2025.116620","url":null,"abstract":"<div><div>Two lithologic units have been mapped and studied on the floor of Jezero crater, Mars: Séítah, which consists of layered olivine-rich cumulates, and Máaz, a series of basaltic to trachyandesitic lava flows. While Séítah and Máaz are close in proximity and stratigraphy, their potential geologic and petrological relationship remains unclear. Here, we present observations from the Planetary Instrument for X-ray Lithochemistry (PIXL) of an olivine cumulate outcrop – <em>Issole</em> – within the Séítah formation. The rock analyzed at <em>Issole</em> is a wehrlite dominated by olivine (Fo_46±1) and interstitial phases, including augite, late olivine, spinel, and feldspathic material. Compared to other outcrops from Séítah, <em>Issole</em> is more iron-rich and records substantial alteration processes. We combine mineral chemistry, textural analysis, and thermodynamic modeling to show that Séítah olivines crystallized from a basaltic parent magma, compositionally similar to the most primitive basalts in the Máaz formation. Crystallization of this parent magma produces residual melts that follow the magmatic differentiation trend defined by Máaz basalts. Moreover, the mineral assemblages predicted by our model during crystallization are consistent with observations from Séítah rocks but show some differences in composition. These differences can be reconciled by considering post-cumulus processes that modified the mineral assemblage in Séítah, including Fe<img>Mg exchange between olivine and pyroxene. Our results indicate that Séítah and Máaz are likely genetically related, and their formation involved both accumulation of crystals at depth and eruption of lavas. The emplacement of Séítah likely occurred as a near-surface, sill-like igneous intrusion into previously erupted Máaz lava flows. The relationship between Séítah and Máaz demonstrates that magmatic differentiation processes, similar to those responsible for the formation of some Martian meteorites, can produce highly diverse lithologies and mineral textures in the Martian crust.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116620"},"PeriodicalIF":2.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How does topography affect wind abrasion on Mars? Recently observed shifts in ventifact orientation at Gale crater","authors":"Daniel Y. Zhou ,&nbsp;Madison L. Turner ,&nbsp;William Rapin ,&nbsp;Juergen Schieber ,&nbsp;Amelie L. Roberts ,&nbsp;Aster C. Cowart ,&nbsp;Megan E. Hoffman ,&nbsp;Bernard Hallet ,&nbsp;Steve G. Banham ,&nbsp;Deirdra Fey ,&nbsp;Kevin W. Lewis ,&nbsp;Sanjeev Gupta ,&nbsp;Claire E. Newman ,&nbsp;Ashwin R. Vasavada ,&nbsp;Cathy M. Weitz ,&nbsp;William E. Dietrich ,&nbsp;John A. Grant ,&nbsp;Daniel Viúdez-Moreiras ,&nbsp;Edwin S. Kite","doi":"10.1016/j.icarus.2025.116605","DOIUrl":"10.1016/j.icarus.2025.116605","url":null,"abstract":"<div><div>Wind abrasion is the dominant erosive process inferred from observations by <em>Curiosity</em> during its traverse in Gale crater, but how and how fast wind scours Mount Sharp is unclear. Here, we infer formative wind direction from ventifacts (wind-eroded rock fragments) measured from <em>Curiosity</em>'s recent traverse. We compare these measurements to previous ones and to wind model predictions, and attempt to estimate the current rate of wind erosion near <em>Curiosity</em>'s location on Mount Sharp. Ventifacts in this study indicate winds blowing south-southeast, agreeing with previous studies on the floor of Gale crater, but differing from studies at the base of the mountain slope. Upslope abrasive wind flows predominate, consistent with idealized models. At some sites, ventifacts are oriented both upslope and downslope on Mount Sharp, suggesting bimodal wind direction at the mountain, agreeing with circulation models that predict diurnal reversals. Using crater-retention age statistics at one site, we estimate a ∼ 3.5 ± 0.8 μm/Earth year (yr) upslope horizontal erosion rate at Mount Sharp. We suggest the observed ventifacts formed when Mars' obliquity and climate regime were similar to those in the present day.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116605"},"PeriodicalIF":2.5,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}