Icarus最新文献

{"title":"Inferred wind and surface conditions during the descent and landing of Beagle 2 on Mars","authors":"M.D. Paton ,&nbsp;P.M. Grindrod ,&nbsp;T. Bertrand ,&nbsp;J.M. Davis ,&nbsp;A.-M. Harri ,&nbsp;H. Savijärvi ,&nbsp;C. Segonne","doi":"10.1016/j.icarus.2025.116728","DOIUrl":"10.1016/j.icarus.2025.116728","url":null,"abstract":"<div><div>Beagle 2 was a British-built lander sent to Isidis Planitia on Mars in 2003. It was part of ESA's Mars Express mission to conduct astrobiology investigations on the surface but failed to communicate after landing. The lander and its jettisoned hardware were eventually discovered on the surface in images taken from orbit. These items preserve information about the wind conditions during the descent and landing. Deciphering the location of these items allows us a glimpse into the atmospheric circulation on Mars and hence an opportunity to verify atmospheric models. In addition, the knowledge can help improve our understanding of the conditions during Beagle 2's descent and landing.</div><div>We found the winds during the initial part of the descent to be consistent with the expected large-scale circulation, especially in terms of wind direction, i.e., a complex interaction between Hadley circulation, stationary waves and the thermal tide. The mean wind speed and direction in the lower part of the descent were found to be consistent with a strong circulation in the basin, driven by slope winds on its rim. As well as the wind conditions we were able to provide some constraints on the surface properties. From modelling the bouncing trajectory of the airbags, there is some indication they were deflected to the side after impact perhaps by an uneven surface, e.g. impact with the Transverse Aeolian Ridges (TARs) as observed in the HiRISE images.</div><div>We have inferred wind speed and direction profiles for the descent and landing of Beagle 2. This study indicates that the wind conditions during the descent of Beagle 2 were likely in line with atmospheric model predictions. The study has been useful for verifying atmospheric models and constraining the range of conditions during the descent and landing of Beagle 2.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116728"},"PeriodicalIF":2.5,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604608","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":"Physical characteristics of Martian south polar ices determined by spatial- and intimate-mixture modeling","authors":"Wendy M. Calvin ,&nbsp;Samuel F.A. Cartwright ,&nbsp;Ava E. Covington","doi":"10.1016/j.icarus.2025.116732","DOIUrl":"10.1016/j.icarus.2025.116732","url":null,"abstract":"<div><div>Twenty-one spectral types for the perennial Martian south polar ices were determined from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data using k-means clustering. These data are higher spatial resolution than any previous measurement of these ices. We present both linear and radiative transfer models of those CRISM spectral types to determine the relative abundance and effective grain size of the three components that make up these surfaces: carbon dioxide ice, water ice and non-ice material. Most cluster means are well represented by a linear combination of five spectra, two types of CO₂ ice, two types of water ice and a non-ice surface. To first order, each CRISM pixel is comprised of sub-pixel spatial mixtures of these five. We then use radiative transfer models to determine the best fit effective grain size and relative abundance of the five components. We use a relatively featureless area of the polar layered deposits for the non-ice component. Our models are consistent with prior modeling work and show very large grain sizes (mm to cm) in the residual CO₂ with very small amounts of water (&lt;0.04 wt%). Water dominated terrains have a wide range of grain sizes but are uniformly ∼80 % water ice. We identify a unique spectral type (C1) that does not have an equivalent in prior studies and may represent CO₂ ice deposited when the atmosphere contained less water vapor following the dust storm of MY28.</div></div><div><h3>Plain language summary</h3><div>Ices at the south pole of Mars show absorption features associated with water ice, carbon dioxide ice and non-ice material. Prior work identified twenty-one spectral types that range in appearance from only carbon dioxide ice (CO₂) to only water ice (H₂O) with many mixtures in between these two. For the first time we model these mixed spectra using both linear least squares statistical approaches and more sophisticated models that account for the interaction of light with individual material grains where different grains are closely packed together. Most mixed spectra are well matched by the simple linear least squares fit of five different components. We then model those five components using the close-packing model. We find for the CO₂ only ices the grains are very large and have minute amounts of water. For water ice dominated spectra they consistently are ∼80 % water 20 % non-ice material. One spectral type is unique and may reflect special conditions that occurred during one year when Mars experienced a large global dust storm.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116732"},"PeriodicalIF":2.5,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588852","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":"Explosive volcanic eruption at Lassell Massif: Implications for lunar silicic volcanism","authors":"Denggao Qiu ,&nbsp;Jianguo Yan ,&nbsp;Jun Huang","doi":"10.1016/j.icarus.2025.116730","DOIUrl":"10.1016/j.icarus.2025.116730","url":null,"abstract":"<div><div>Volcanism manifests as either calm effusive or violent explosive eruptions depending on the gas content of the atmosphere and water interactions. Explosive volcanic eruptions on the Moon are limited by the lack of atmosphere and water; however, recent remote sensing and numerical modeling results suggest that the Moon may have been wet in the past, and thus influenced the form of volcanic eruptions. Lunar morphology, spectral and gravity data are used in this work. Investigations of the topography, chemical composition, and subsurface structure of the Lassell Massif using an oxide content inversion model and a three-dimensional density inversion model reveal that explosive volcanic eruptions did in fact occur on the Moon. A negative ellipsoidal density anomaly with a value of ∼ − 230.5 kg/m³ was identified beneath the northern portion of the Lassell Massif, suggesting that it is a silicic magma chamber. Furthermore, an investigation of the topography and chemical composition of the area shows that magma was ejected to the south. This research provides suggestive insights into the possible presence of endogenic water or other volatile species are present on the Moon. In the future, locations associated with silicic volcanism will be the preferred targets for further lunar investigations of endogenous water.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116730"},"PeriodicalIF":2.5,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144564035","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":"Insights into the mineralogy of the Rantila aubrite: A luminescence and VNIR reflectance spectroscopy study","authors":"Anna-Irene Landi ,&nbsp;Michael Gaft ,&nbsp;Cristian Carli ,&nbsp;Fabrizio Capaccioni ,&nbsp;Giovanni Pratesi","doi":"10.1016/j.icarus.2025.116725","DOIUrl":"10.1016/j.icarus.2025.116725","url":null,"abstract":"<div><div>Rantila aubrite fell in Rantila, Gujarat, India, in August 2022. This study aims to investigate the mineralogy and mineral-chemistry of three fragments of this meteorite and correlate them with reflectance spectroscopy in the visible and near-infrared spectral range (VNIR) and Laser-Induced Time-Resolved Luminescence (LITRL). Aubrites very low Fe²⁺ content prevents luminescence quenching under UV light exposure, allowing these meteorites to exhibit well-defined luminescence. The investigated samples have different appearances. One consists of a light-coloured portion primarily composed of FeO-free enstatite, along with forsterite, diopside, plagioclase, minor sulphides (troilite, alabandite, daubréelite, and (Fe,Ca,Mn,Mg)S), and kamacite. The second sample is composed mainly of the same light-coloured portion and hosts a dark forsterite clast. The third sample is mainly made of dark glass. Minor terrestrial weathering is observed, with the detection of sporadic iron oxides/hydroxides. The chemical composition of the detected phases indicates highly reducing conditions during the formation, as expected for an aubrite. The mineral chemistry is similar among the different fragments in terms of major elements concentrations; some differences are observed for minor elements. Luminescence spectra indicate Cr³⁺ and Mn²⁺ as activators in diopside and forsterite, respectively, for two of the three samples. Ce³⁺ is the activator in the third sample, which lacks forsterite and has lower Cr₂O₃ contents in diopside compared to the other two samples. Therefore, the differences in mineral chemistry observed through electron microprobe analysis (EPMA) are further emphasized by luminescence data. Investigating the luminescence behaviour could provide a valuable contribution to the mineralogical-petrological study of these materials. VNIR reflectance spectra are consistent with low Fe<img>Ca pyroxene and forsterite. The main absorption typical of mafic minerals (∼0.9 μm) is deeper than what has previously been observed in aubrites: this can be related to the slightly higher FeO concentrations, which, despite being very low (&lt;0.4 wt%), still contribute to the absorption. Absorption features at ∼1.4 μm and ∼1.9 μm are consistent with low terrestrial weathering presence. Increasing the knowledge of the correlation between spectral properties and mineralogy/mineral chemistry on highly reduced meteorites will be useful for future investigation of Mercury with the ESA's BepiColombo mission, specifically for the interpretation of the data expected from the Spectrometer and Imagers for MPO BepiColombo Integrated Observatory SYStem (SIMBIO-SYS)/Visible and near Infrared Hyperspectral Imager (VIHI) and Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) instruments</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116725"},"PeriodicalIF":2.5,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597282","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":"Experimental study on thermal and mechanical properties of sintered glass materials: Implication for physical properties of primordial porous materials in the solar system","authors":"Tetsushi Sakurai ,&nbsp;Takuya Ishizaki ,&nbsp;Akiko M. Nakamura","doi":"10.1016/j.icarus.2025.116729","DOIUrl":"10.1016/j.icarus.2025.116729","url":null,"abstract":"<div><div>Planetesimals underwent consolidation processes in the early solar system, which altered their thermal and mechanical properties. Sintering—a process that forms solid necks between particles—is considered one such process in planetesimals, influencing their filling factor, or porosity, as well as their thermal and mechanical properties.</div><div>In this study, to better constrain and understand the thermal and mechanical properties of planetesimals that evolved from initially powdery or granular bodies, as well as those of boulders on small bodies, which are considered remnant planetesimals, we prepared porous sintered samples consisting of glass particles with filling factors ranging from 0.35 to 0.75, corresponding to porosities of 65 % to 25 %. We then measured their thermal diffusivity, elastic wave velocity, and flexural strength, and derived empirical relationships for the normalized values—scaled by those at a filling factor of 1—as functions of filling factor or porosity. The normalized thermal diffusivities and elastic wave velocities of the sintered glass materials in this study showed similar dependencies on the filling factor. Moreover, the upper limits of the normalized elastic wave velocities were consistent with those of snow at corresponding filling factors, suggesting that these upper limits may be independent of the matrix material.</div><div>The derived empirical relationships apply to materials with porosities higher than those of meteorites. We estimated the porosity of a low-thermal-inertia boulder on the surface of asteroid Ryugu based on its thermal inertia, assuming no influence from internal cracks. The result suggests that the boulder's porosity may be higher than values previously reported, and should be regarded as one of the possible porosity estimates.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116729"},"PeriodicalIF":2.5,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588850","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":"“Icy” scarp exposures, “ice-rich” overburdens and ephemeral climate-warming at Mars' mid-latitudes in the very late Amazonian epoch","authors":"Richard J. Soare ,&nbsp;Colman J. Gallagher ,&nbsp;James B. Garvin ,&nbsp;Jean-Pierre Williams ,&nbsp;Adam J. Hepburn ,&nbsp;Francois Costard ,&nbsp;Michelle Koutnik ,&nbsp;An Y. Li","doi":"10.1016/j.icarus.2025.116727","DOIUrl":"10.1016/j.icarus.2025.116727","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Most chronologies of Mars' climate history suggest that Mars' climate has undergone a relatively linear evolution, i.e. from cool and ephemerally-wet Late Noachian/Early Hesperian Epoch boundary conditions to the very Late Amazonian Epoch where extreme aridity, sparse water-vapour pressure and largely sub-zero (celsius) mean temperatures rule at non-polar latitudes. Against this backdrop, icy-surface accumulation and glacial features, forms and landscapes are expected; the freeze-thaw cycling of water at or near the surface and the associated development of &lt;em&gt;ice-rich&lt;/em&gt; periglacial landscapes rooted in &lt;em&gt;wet&lt;/em&gt; processes are not. Here, we use an &lt;em&gt;icy&lt;/em&gt; (glacial) scarp exposure (&lt;em&gt;HiRISE&lt;/em&gt; image ESP 0500477_1220) and its possible &lt;em&gt;ice-rich&lt;/em&gt; (periglacial) overburden as a case study of other icy-scarp exposures on Mars. We suggest that the icy flow-forms that embrace our case-study scarp and others elsewhere &lt;strong&gt;(see Table-1)&lt;/strong&gt; either could be: relicts of a high-amplitude glacial system and regional climate-variations; or of a post-glacial transition characterised by low-amplitude climate oscillations that drove rhythmic slope-activity. We also propose that the icy scarp exposures, orientation and retrogression is the work of preferential insolation/sublimation and of regional/local winds. Often, wind-streaks and blow-outs are observed adjacent to icy-scarp headwalls. These features are the result of headwall erosion by the work of wind and of icy/lithic mass loss by sand-blasting or enhanced radiative exposure. We also note that some of the wind-streaks and blow-outs vary over time (through to the present day) in: presence/absence; surface coverage, and/or darkness/lightness. This suggests that aeolian activity is diachronic and current. Based on a suite of morphological similarities with ice-rich permafrost regions on Earth such as the Tuktoyaktuk Coastlands in northern Canada, we propose that the icy-scarp and ice-rich overburden at our case-study location are pre- and post-dated by features and forms that are/were ice-rich too, i.e. formed by the freeze-thaw cycling of water. These features and forms include: &lt;strong&gt;1)&lt;/strong&gt; contiguous low and high centred polygons, possibly underlain by (aggraded or degraded) ice wedges at the margins; &lt;strong&gt;2)&lt;/strong&gt; interconnected channels of polygon corner/trough pits, perhaps formed by the sublimated loss of ice-wedges; and, 3&lt;strong&gt;)&lt;/strong&gt; alas-like depressions, suggestive of thermokarst that has undergone ice-loss, in this case, by sublimation. Ice depletion by sublimation is not-inconsistent with ice enrichment by the freeze-thaw cycling of water and there is no necessary reason to believe that enrichment and depletion periods on Mars were/are concomitant. Moreover, ice-rich landscapes on Earth have been observed to develop in extremely short periods of time, as little as ∼10&lt;sup&gt;−1&lt;/sup&gt; years. As such, small and favourable windows of climatic ","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116727"},"PeriodicalIF":2.5,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633282","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":"Comparing Navcam dust devil detections to transient daytime convective vortex signatures in REMS pressure and ultraviolet data","authors":"Emily L. Mason ,&nbsp;Scott D. Guzewich ,&nbsp;Christopher Edwards ,&nbsp;Álvaro Vicente-Retortillo ,&nbsp;Daniel Viúdez-Moreiras","doi":"10.1016/j.icarus.2025.116726","DOIUrl":"10.1016/j.icarus.2025.116726","url":null,"abstract":"<div><div>The Mars Science Laboratory (MSL) Curiosity rover has collected over seven Mars Years (MY) of meteorological data. We compare visible dust devil detections in Navigational Camera (Navcam) observations to signatures detected using the Rover Environmental Monitoring Station (REMS) pressure and Ultraviolet (UV) Sensors. Using methodology from previous work, we search for pressure drops and corresponding transient decreases in the UV signal to detect dust-laden vortex signatures that can be compared to dust devil detections from Navcam. Results from these detections show a strong seasonality and topographical influence in pressure drops, but coincident UV drops, which are indicative of dust-laden vortices, tend to be more frequent in certain locations and do not strictly follow this seasonality. Diurnal patterns in dust devil detections by REMS compare well with Navcam detections, with a strong increase in these detections near 10:00 LTST, a peak near local noon, a gradual decrease in afternoon hours, and some interannual variability. UV detections fall off towards Marker Band Valley, an area with high surface thermal inertia and limited sand cover, as do Navcam detections, suggesting that sand availability plays an important role in where dust devils are forming.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116726"},"PeriodicalIF":2.5,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571874","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":"Constraining the survival of HCN during cometary impacts","authors":"Catriona H. McDonald ,&nbsp;Amy Bonsor ,&nbsp;Auriol S.P. Rae ,&nbsp;Paul B. Rimmer ,&nbsp;Richard J. Anslow ,&nbsp;Zoe R. Todd","doi":"10.1016/j.icarus.2025.116704","DOIUrl":"10.1016/j.icarus.2025.116704","url":null,"abstract":"<div><div>Cometary impacts have been invoked as an atmosphere-independent method of stockpiling hydrogen cyanide (HCN), a key prebiotic feedstock molecule, into environments favourable for the onset of prebiotic chemistry on the early Earth. This work revisits the prospects for cometary delivery of HCN through new impact simulations of idealised cometary bodies using the shock physics code iSALE combined with simple chemical modelling. Using temperature and pressure profiles for material within spherical, non-porous comets with a high resolution of Lagrangian tracer particles, we assess the survival rate of HCN across a range of impact velocities, sizes, and angles, assuming both steady state and equilibrium chemistry. We find that HCN survival is extremely limited at impact velocities above the escape velocity of the Earth, unless the impact occurs at extreme obliquity (<span><math><mrow><mi>θ</mi><mo>∼</mo><mn>15</mn><mo>°</mo></mrow></math></span>). We present a parametrisation of the survival of HCN as a function of impact velocity, angle, and cometary diameter, which provides an upper limit to survival in more realistic scenarios to aid with future studies investigating the role of comets in the origins of life. Although successful HCN delivery may be possible in our idealised model, we neglect to consider the effect of atmospheric passage, and our results suggest that delivery alone is not likely to be sufficient for the onset of prebiotic chemistry.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116704"},"PeriodicalIF":2.5,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549335","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":"Particle size and albedo effects on emissivity spectra of lunar analog minerals and rocks in the intermediate infrared region","authors":"Nandita Kumari ,&nbsp;John Mustard ,&nbsp;Timothy D. Glotch","doi":"10.1016/j.icarus.2025.116721","DOIUrl":"10.1016/j.icarus.2025.116721","url":null,"abstract":"<div><div>Visible/near-infrared (VNIR) and thermal infrared (TIR) spectroscopy have been widely used to detect and characterize the abundances of silicates across the solar system. Recently, intermediate infrared (IMIR) reflectance spectroscopy (∼4 - 6 μm) has been proposed as a tool to quantify the Mg# in olivine and pyroxene with varying iron, magnesium and calcium content. The lunar surface is composed of rocks with mixed particle sizes and thus quantifying the effects of particle size is extremely important to increase the robustness of IMIR spectroscopy as a tool for lunar surface exploration. Similarly, space weathering has been known to cause optical darkening and affect the spectra of the lunar surface materials across a broad wavelength range. In this study, we have identified the emission features of lunar analog minerals/rocks and their variations with changes in particle sizes and albedo at IMIR wavelengths in simulated lunar environment (SLE). We find that the lunar analog minerals display an increase in emissivity and striking decrease in feature contrast with an increase in particle sizes or decrease in albedo. This study shows that while this wavelength range works well in reflectance space for sample characterization, using it for emissivity measurements via orbital remote sensing or in-situ rovers requires extensive study.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116721"},"PeriodicalIF":2.5,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144564034","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":"Modeling barometric pumping of martian methane: Implications for Perseverance sample timing and gas loss from drilled cores","authors":"John P. Ortiz ,&nbsp;Kevin W. Lewis ,&nbsp;Roger C. Wiens ,&nbsp;Philip H. Stauffer ,&nbsp;Dylan R. Harp ,&nbsp;Harihar Rajaram","doi":"10.1016/j.icarus.2025.116702","DOIUrl":"10.1016/j.icarus.2025.116702","url":null,"abstract":"<div><div>There are many challenges surrounding the interpretation of martian methane signatures. Atmospheric methane variations detected by the Sample Analysis at Mars (SAM) instrument on board the <em>Curiosity</em> rover remain difficult to explain given the lack of a confirmed methane transport mechanism from subsurface sources. Furthermore, the biogenic or abiogenic origin of martian methane cannot be determined outside of isotopic analysis in an Earth-based laboratory. Building on our previous work modeling barometrically driven seepage of methane through fractured rock coupled to a simplified atmospheric mixing scheme, we now use the same model framework to estimate the methane concentration in the shallow subsurface. Our results indicate that subsurface methane levels also exhibit strong seasonal and diurnal variability, with peak concentrations occurring during specific windows of time that depend on both solar and atmospheric forcing.</div><div>This insight has implications beyond Gale crater. At Jezero crater, where the <em>Perseverance</em> rover is collecting samples for potential return to Earth, strategic selection of sampling times could enhance the chances of recovering methane-bearing rock. Our results suggest that the timing of sample collection – both time of day and time of year – can significantly affect the likelihood of capturing methane within the collected cores if barometric pumping is a significant driving factor. Sample timing optimization could increase the potential for detecting organics or signatures of habitability in Mars Sample Return, augmenting the overall scientific return of the Mars 2020 mission and possibly bringing us closer to understanding the origin of methane on Mars. However, a preliminary analysis of methane loss rates from collected samples indicate that unless sample tubes can be sealed within a few hours of collection, the majority mass fraction of methane is likely to escape.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116702"},"PeriodicalIF":2.5,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514369","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}