Icarus最新文献

{"title":"Ultrasonic velocities of icy powdered rock with implications for seismic resource exploration on the moon","authors":"C.C. Amos ,&nbsp;M. Prasad ,&nbsp;K.M. Cannon ,&nbsp;C.B. Dreyer","doi":"10.1016/j.icarus.2025.116509","DOIUrl":"10.1016/j.icarus.2025.116509","url":null,"abstract":"<div><div>Although water ice has been detected by satellite observations near the lunar poles, it is unknown if this ice is simply frost on the Moon's surface or if larger ice deposits exist in the subsurface. If ice is present within the subsurface, it is unknown if this ice exists as loose ice grains or as a cement that binds regolith grains together. To create an economically viable extraction and production plan for lunar water ice resources, we must characterize near-surface ice concentration and distribution at small (&lt;10 m) spatial and depth scales. Geophysical methods that can be deployed on the Moon's surface, such as seismic surveying, could supply some of this information for future lunar mine planning. To improve our understanding of how seismic surveying may detect and characterize subsurface lunar ice, we performed laboratory ultrasonic velocity measurements of lunar regolith simulant with variable amounts of granular and cementing ice. These measurements were performed under variable confining pressure (0.005–0.08 MPa) and constant low temperature (−26 °C). We used these measurements to calibrate a rock physics model to predict seismic velocity as a function of porosity, pressure, ice concentration and ice texture. Our results show that seismic velocity increases with ice concentration, and this increase is roughly 20 times higher for cementing ice than for granular ice. Our model can be used in future studies to predict how effective seismic methods may be for detecting and characterizing subsurface lunar ice deposits with varying ice properties and geologic complexity.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116509"},"PeriodicalIF":2.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548642","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":"The mystery of the missing mantle problem and insights from spectroscopy","authors":"B.G. Rider-Stokes ,&nbsp;S.L. Jackson ,&nbsp;T.H. Burbine ,&nbsp;R.C. Greenwood ,&nbsp;E.M. MacLennan ,&nbsp;L.F. White ,&nbsp;S.S. Russell ,&nbsp;M. Anand ,&nbsp;M.M. Grady","doi":"10.1016/j.icarus.2025.116506","DOIUrl":"10.1016/j.icarus.2025.116506","url":null,"abstract":"<div><div>Differentiation of planetesimals results in the segregation of materials, with the densest materials sinking, producing a metallic core, while the lighter fraction, rises, fabricating a crust. While there are multiple examples of planetary crusts (e.g., V-type asteroids) and metallic cores (e.g., M-type asteroids), there appears to be a scarcity of mantle-like materials in both the asteroid (e.g., A-type asteroids) and meteorite record. This lack of olivine-dominated material has been dubbed ‘The Missing Mantle Problem’. Here we measure the reflectance spectra of four olivine-rich meteorites expected to originate from the mantle of differing planetesimals. Following the Bus-DeMeo taxonomy, NWA 12264 and Chassigny can be classified as Sa-types, while NWA 8535 and NWA 15717 are classified as Q-types. This result implies that mantle-like materials are not restricted to A-type asteroids as previously expected. This study provides a significant step toward the resolution of the apparent shortage of olivine-rich material in the early Solar System.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116506"},"PeriodicalIF":2.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-instrument sounding of a Jovian thunderstorm from Juno","authors":"Shawn R. Brueshaber ,&nbsp;Zhimeng Zhang ,&nbsp;John H. Rogers ,&nbsp;Gerald Eichstädt ,&nbsp;Glenn S. Orton ,&nbsp;Davide Grassi ,&nbsp;Leigh N. Fletcher ,&nbsp;Cheng Li ,&nbsp;Shinji Mizumoto ,&nbsp;Alessandro Mura ,&nbsp;Fabiano Oyafuso ,&nbsp;Ramanakumar Sankar ,&nbsp;Michael H. Wong ,&nbsp;Candice J. Hansen ,&nbsp;Steven Levin ,&nbsp;Scott Bolton","doi":"10.1016/j.icarus.2025.116465","DOIUrl":"10.1016/j.icarus.2025.116465","url":null,"abstract":"<div><div>Thunderstorms play a significant role in transporting heat from the deep interior to space on giant planets. We present observations of a 3,400-km wide thunderstorm complex in Jupiter’s North Equatorial Belt (NEB) during the 38th periapse of the Juno spacecraft on 29 Nov. 2021. Data were acquired by the Microwave Radiometer (MWR), the visible light JunoCam instrument, the Jovian InfraRed Auroral Mapper (JIRAM), and from supporting Earth-based imaging. This was the first time Juno was able to observe a thunderstorm at suitably low emission angles with multiple instruments at close range (<span><math><mo>∼</mo></math></span>5,690 km), making it the most comprehensive close-up assessment of a Jovian thunderstorm to date. Lightning detection confirmed the Storm’s vigorous convective nature. MWR brightness temperatures indicate this Storm appears to be wholly contained within the weather layer, i.e., no deeper than the expected base of the H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O cloud, and not as a result of any detected deep-seated upwelling beneath the H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O cloud base. Earth-based observations tracked it over its <span><math><mo>∼</mo></math></span> 2-week lifespan, providing evidence that mesoscale-to-synoptic-scale forcing mechanisms were involved in sustaining it, including the intriguing possibility of a humidity front (‘dryline’), a sharp gradient in the vapor abundance, promoting lift along a concentrated region.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116465"},"PeriodicalIF":2.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420863","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":"Synthesized microstructures and reflectance spectra of solids in the ice Ih–MgCl2•12H2O system: Implications for Europa","authors":"Thomas B. Czernik ,&nbsp;Kevin Robertson ,&nbsp;Cameron Meyers ,&nbsp;Christine McCarthy ,&nbsp;Greg Hirth ,&nbsp;Reid F. Cooper","doi":"10.1016/j.icarus.2025.116481","DOIUrl":"10.1016/j.icarus.2025.116481","url":null,"abstract":"<div><div>The existence of hydrated MgCl₂ on Europa's surface has been suggested by remote sensing spectrometry, but this interpretation is limited by the low signal-to-noise ratio of the data and a lack of relevant laboratory-derived spectra within spectral libraries. Furthermore, the compaction state of Europa's surface remains poorly constrained, yet there is a lack of laboratory-measured spectra for dense specimens that are necessary to understand endmember behavior of a dense surface. We acquired vis-near-infrared reflectance spectra at wavelengths from 0.35 to 2.5 μm for synthetic specimens in the ice Ih–MgCl₂•12H₂O system. Reflectance spectra were measured for dense water-ice aggregates with different grain sizes and were used to assess the influence of density on spectral signature. In general, large-grained aggregates exhibited decreased albedo, broadening of absorption bands, and decreased absorption band depth. Additionally, reflectance spectra of powdered MgCl₂•12H₂O were measured as a function of particle size and were observed to contain spectral features distinct from other hydration states (MgCl₂•nH₂O, <em>n</em> = 1,2,4,6,8). Particle size dependency observed in the spectra of powdered MgCl₂•12H₂O mirrored grain size dependent trends observed in the spectra of dense water-ice aggregates. We also measured the spectra of eutectic (20.6 wt% MgCl₂) and porphyritic hypoeutectic (7.7 and 16.4 wt% MgCl₂) dense ice Ih–MgCl₂•12H₂O aggregates. We argue that the microstructures of synthesized eutectic and hypoeutectic aggregates are suitable to represent texture likely existent in Europa's shell and are appropriate for use in mechanical testing where texture needs to be carefully considered.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116481"},"PeriodicalIF":2.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New observations of topographic slumps in Valles Marineris, Mars: Investigating the role of recurring slope lineae","authors":"Amelia Ascione ,&nbsp;Lujendra Ojha ,&nbsp;Matthew Chojnacki ,&nbsp;Vidushi Dhaka","doi":"10.1016/j.icarus.2025.116503","DOIUrl":"10.1016/j.icarus.2025.116503","url":null,"abstract":"<div><div>Small-scale landslides, termed topographic slumps, are commonly co-located with seasonally active recurring slope lineae (RSL) on Mars. Previously identified topographic slumps initiated beneath or around the terminal points of RSL, suggesting that RSL activity may trigger slump formation. In this study, we conducted a comprehensive survey of HiRISE images spanning Mars years (MY) 29 to 37 in the southern mid-latitudes, northern mid-latitudes, and equatorial latitudes. We report eight newly identified topographic slumps that formed over the past 4 Mars years. Despite a comprehensive survey, these slumps were exclusively observed on slopes within Valles Marineris. While most of these slumps were co-located with RSL, two occurred on slopes lacking any detectable RSL activity. All slumps, however, formed on steep slopes (&gt;27°) with inferred high sediment supply. We analyzed slump morphologies, seasonalities, and slope parameters to discuss potential topographic slump formation mechanisms. We suggest that if RSL are dry granular flows, gradual oversteepening due to debris accumulation beneath their termini could promote slumping. However, the limited number of topographic slumps relative to the widespread occurrence of RSL suggests that these features may be unrelated, or that unknown alternative conditions are necessary to initiate slump formation.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116503"},"PeriodicalIF":2.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429605","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":"Extensional structures at lunar lobate scarps","authors":"Thomas Frueh ,&nbsp;Ralf Hetzel ,&nbsp;Thomas R. Watters ,&nbsp;Carolyn H. van der Bogert ,&nbsp;Jaclyn D. Clark ,&nbsp;Cole Nypaver ,&nbsp;Harald Hiesinger","doi":"10.1016/j.icarus.2025.116493","DOIUrl":"10.1016/j.icarus.2025.116493","url":null,"abstract":"<div><div>The Moon's lithosphere has been in a net compressional stress regime for the past 3.6 billion years, leading to the formation of globally distributed kilometer-scale thrust faults that form lobate scarps at the surface. Lobate scarps are among the youngest features on the lunar surface. A sign of their recent activity is the presence of meter-scale extensional structures in their hanging walls, which are generally either parallel or perpendicular to the scarp-forming thrust fault. However, the origin of these structures and their orientation relative to the primary fault is not well understood. Here, we present detailed tectonic maps of three lobate scarps (Lee-Lincoln, Lilius C-1, and Morozov-1), which reveal sets of fault-perpendicular to fault-parallel extensional structures at all scarps. Using high-resolution digital elevation models, we measure along-strike variations in fault throw and document maximum throws of ∼216 m for Lee-Lincoln, ∼98 m for Lilius C-1, and ∼140 m for Morozov-1. By comparison with terrestrial analogs, we show that fault-parallel extensional structures are mainly formed by flexural bending of the hanging wall, whereas fault-perpendicular features are potentially formed by along-strike variations in thrust orientation, and potential strike-slip components on the thrust fault. We hypothesize that small extensional structures preferably either form near the main displacement, at the most recently active regions of a scarp, or at segment boundaries. Based on degradation-rate estimates, we propose that small graben provide the best evidence for very recent activity of lobate scarp faults, because the graben form during coseismic slip events on the thrust faults.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116493"},"PeriodicalIF":2.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boulder-induced spin variability in the YORP effect","authors":"Dahlia A. Baker,&nbsp;Jay W. McMahon","doi":"10.1016/j.icarus.2025.116487","DOIUrl":"10.1016/j.icarus.2025.116487","url":null,"abstract":"<div><div>Boulders have been observed as a dominant feature on all rubble-pile asteroids, as seen by recent survey missions to small bodies. Thermal re-radiation induced torque, known as the YORP effect, is a dominant influence on the rotational dynamics of a body in the rubble-pile size regime below 1 km in diameter. YORP is also extremely sensitive to small-scale topography such as regolith, boulders, and craters. We analyze the effects of boulders on the YORP spin torque of an asteroid, where simulated populations are based on the observed size and placement distributions on real bodies, to show how influential these features are when making YORP estimates. Models are produced by adding many geometric boulder shapes to an existing asteroid shape model. This analysis applies previous polyhedral YORP approximations which calculate the spin and obliquity coefficients through summation over faceted shapes. YORP is seen to be highly variable with boulder size, placement, and dominant orientation on both Bennu and Itokawa shape models. We find that the maximum influence due to a boulder can be up to 135% of the total YORP when large boulders affect the dynamics or several small ones have a combined effect. For a single feature, this is a large and highly sensitive and variable global influence and represents the maximum of the observed size range. These results also pertain to a static case, while there is expected material redistribution and breakup through the experience of YORP spin changes which may be a factor in limiting unbounded YORP spin-up or spin-down over time. We compare the magnitude and uncertainty of boulder-induced YORP torque to other analytical models.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"431 ","pages":"Article 116487"},"PeriodicalIF":2.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386432","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":"Exploring water-ice deposits in lunar polar craters with Chandrayaan-2 DFSAR data","authors":"Nidhi Verma ,&nbsp;Megha Bhatt ,&nbsp;Mayand Dangi ,&nbsp;Shashi Kumar ,&nbsp;Anil Bhardwaj","doi":"10.1016/j.icarus.2025.116492","DOIUrl":"10.1016/j.icarus.2025.116492","url":null,"abstract":"<div><div>Detection of water-ice deposits using synthetic aperture radar (SAR) is a cost-effective, and efficient approach to understand lunar water resources. As water is crucial to supporting human-based space exploration, current and near upcoming lunar missions are primary concentrated on mapping and quantification of water ice exposures on surface and subsurface levels. The circular polarization ratio greater than one (CPR &gt;1) derived using the orbital radar observations is considered as an important SAR derived parameter for water-ice detection. This study aims to investigate 14 craters near the lunar poles with high CPR (CPR &gt;1), as identified in previous studies, using the L-band (24 cm) dual frequency synthetic aperture radar (DFSAR) onboard Chandrayaan-2. In addition to CPR, we computed the degree of polarization (DOP) after applying parallax error correction that helps in reducing misinterpretation. Our findings are based on orthorectified DFSAR calibrated data analysis. We found that the CPR of crater interiors is not significantly different from that of their surroundings, and this pattern is consistent throughout all the 14 craters selected. Further, we also found a linear inverse relationship between CPR and DOP for the interior and exteriors of the craters, with R² ∼ 0.99, indicating a strong correlation between these two parameters. We found only ∼2 % of total pixels are above CPR &gt; 1, which indicates that there is less possibility of homogeneous water-ice but the possibility of water-ice mixed with the subsurface regolith cannot be ruled out.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116492"},"PeriodicalIF":2.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420862","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":"Secondary scattering shape from shading for precise terrain reconstruction of the lunar permanently shadowed regions","authors":"Jia Qian ,&nbsp;Zhen Ye ,&nbsp;Siyi Qiu ,&nbsp;Rong Huang ,&nbsp;Huan Xie ,&nbsp;Yusheng Xu ,&nbsp;Xiaohua Tong","doi":"10.1016/j.icarus.2025.116494","DOIUrl":"10.1016/j.icarus.2025.116494","url":null,"abstract":"<div><div>High-resolution digital elevation models (DEMs) of permanently shadowed regions (PSRs) at the lunar South Pole are crucial for upcoming exploration missions. Recent advances, such as high-resolution images acquired from ShadowCam, utilize indirect lighting to image PSRs. This provides data for the Shape from Shading (SFS) technique, which can extract subtle topographic details from single-image to reconstruct high-resolution terrain. However, traditional SFS methods are not suitable for complex secondary scattering scenes in PSRs with multiple secondary light sources. To address this issue, a novel secondary scattering SFS (SS-SFS) method is developed for pixel-wise 3D reconstruction of PSR surfaces, which utilizes indirect illuminated imagery and the corresponding low-resolution DEM to generate DEM with high resolution matches the input image. The proposed method effectively extracts and simplifies multiple incident facets associated with each shadowed facet through clustering, while constructing and optimizing the SS-SFS loss function. Experiments were conducted using ShadowCam images of two areas including both PSRs and temporary shadowed areas, to demonstrate the performance of the proposed method. The SS-SFS DEMs effectively capture intricate topographic details, and comparisons with adjusted Lunar Orbiter Laser Altimeter laser points indicate that the SS-SFS DEMs exhibit high overall accuracy. The high-resolution slope map of PSRs was calculated based on the SS-SFS DEMs, and overcome the limitation that surface slope is relatively underestimated from LOLA DEMs. Additionally, the SS-SFS DEMs were comprehensively compared with the traditional SFS DEMs generated using Narrow Angle Camera imagery in a small temporarily shadowed area, revealing strong consistency and further validating the effectiveness of detailed reconstruction. Overall, the proposed SS-SFS method is essential for generating high-resolution DEMs of PSRs, supporting future lunar South Pole exploration missions.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"431 ","pages":"Article 116494"},"PeriodicalIF":2.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377063","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":"A numerical model for the atmospheric entry of hydrated, phyllosilicate-rich micrometeorites","authors":"G. Micca Longo ,&nbsp;M.D. Suttle ,&nbsp;S. Longo","doi":"10.1016/j.icarus.2025.116490","DOIUrl":"10.1016/j.icarus.2025.116490","url":null,"abstract":"<div><div>Numerical modelling is crucial for understanding micrometeorite atmospheric entry, yet most existing models treat cosmic dust grains as chemically inert, anhydrous particles. In contrast, empirical studies of micrometeorites recovered on Earth reveal that hydrated, phyllosilicate-bearing particles, similar to the fine-grained matrix of carbonaceous chondrites, dominate the cosmic dust flux at size fractions above ∼100 μm. The thermal decomposition of phyllosilicates is expected to play a significant but currently unmodelled role in reducing peak temperatures during entry, thereby increasing the likelihood of their survival to the Earth's surface. To address this, we developed the first numerical model simulating the thermal response of phyllosilicate-dominated micrometeorites during atmospheric entry. Building on the Love and Brownlee (1991, Icarus, 89:26-43) model, we incorporate both sub-solidus decomposition and supra-solidus evaporation processes, as constrained by thermogravimetric analysis data from heating experiments on cronstedtite and saponite, reflecting the main phyllosilicate species found in CM, CR and CI chondrites. Three factors are crucial in determining the decomposition behaviour of phyllosilicate-dominated micrometeorites during entry: (1) grain density (d), (2) enthalpy of dehydration (Q), and (3) the volatile budget (<span><math><mi>ζ</mi></math></span>_max). Of these, density is the most influential. The sub-solidus loss of water helps reduce peak temperatures in phyllosilicate micrometeorites, but the effect, compared to anhydrous olivine, is modest (&lt;35 °C for cronstedtite and &lt;100 °C for saponite, on average). Furthermore, on average, saponite experiences peak temperatures that are 76 °C lower than those of cronstedtite. This is despite cronstedtite having a higher enthalpy of decomposition and a larger volatile budget. This effect is attributed to cronstedtite's higher density, which leads to more intense thermal processing, creating thermal histories similar to olivine-dominated micrometeorites. Since CI chondrites contain saponite, CI-like micrometeorites are more likely to survive entry without melting compared to CM-like micrometeorites under the same conditions. Finally, our results suggest that hydrated micrometeorites &gt;50 μm are likely to survive atmospheric entry without loss of water only in grazing scenarios (entry angles &gt;80°, where entry angle is measured from zero with respect to the zenith), this accounts for the rarity of hydrated fine-grained micrometeorites that contain intact crystalline phyllosilicates, as reported from petrographic studies of unmelted cosmic dust.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"431 ","pages":"Article 116490"},"PeriodicalIF":2.5,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}