Journal of Geophysical Research: Planets最新文献

{"title":"Vapor Condensates on the Most Pristine Black Beads From a Clod in Apollo Drive Tube 73001: Discovery of Lunar NaCl Nanocrystals","authors":"Yang Liu,&nbsp;Chi Ma","doi":"10.1029/2024JE008444","DOIUrl":"https://doi.org/10.1029/2024JE008444","url":null,"abstract":"<p>Identification of the mineral species of vapor condensates on the surface of lunar pyroclastic beads, formed during the flights of beads in the lunar volcanic plume, helps to constrain the physical and chemical conditions of the lunar volcanic plume. We conducted nanomineralogy studies of vapor condensates on the surface of pristine black beads from a clod that was extracted from the recently opened Apollo drive tube 73001. This drive tube had been sealed under vacuum since its collection on the Moon and thus represents the most pristine sample in allocatable Apollo collection. Vapor condensates observed on the surface include patches made of ZnS nanocrystals and possible rare scattered NaCl nanocrystals. ZnS nanocrystals were previously found on Apollo 15 green and yellow beads, but NaCl nanocrystals are unique to black beads. Both ZnS and NaCl nanocrystals are absent in Apollo 17 74220 orange beads. Although orange and black beads are of similar chemistry, black beads in the clod 73001, 226 could form from a different environment.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations of Water Frost on Mars With THEMIS: Application to the Presence of Brines and the Stability of (Sub)Surface Water Ice","authors":"L. Lange,&nbsp;S. Piqueux,&nbsp;C. S. Edwards,&nbsp;F. Forget,&nbsp;J. Naar,&nbsp;E. Vos,&nbsp;A. Szantai","doi":"10.1029/2024JE008489","DOIUrl":"https://doi.org/10.1029/2024JE008489","url":null,"abstract":"<p>Characterizing the exchange of water between the Martian atmosphere and the (sub)surface is a major challenge for understanding the mechanisms that regulate the water cycle. Here we present a new data set of water ice detected on the Martian surface with the Thermal Emission Imaging System (THEMIS). The detection is based on the correlation between bright blue-white patterns in visible images and a temperature measured in the infrared that is too warm to be associated with <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>CO</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${mathrm{CO}}_{2}$</annotation>\u0000 </semantics></math> ice and interpreted instead as water ice. Using this method, we detect ice down to 21.4°S, 48.4°N, on pole-facing slopes at mid-latitudes, and on any surface orientation poleward of 45° latitude. Water ice observed with THEMIS is most likely seasonal rather than diurnal. Our data set is consistent with near-infrared frost detections and predictions by the Mars Planetary Climate Model. Water frost average temperature is 170 K, and the maximum temperature measured is 243 K, lower than the water ice melting point. Melting of pure water ice on the surface is unlikely due to cooling by latent heat during its sublimation. However, 243 THEMIS images show frosts that are hot enough to form brines if salts are present on the surface. The water vapor pressure at the surface, calculated from the ice temperature, indicates a dry atmosphere in early spring, during the recession of the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> ice cap. The large amount of water vapor released by the sublimation of warm frost cannot stabilize subsurface ice at mid-latitudes.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008489","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Thermal Structure and Composition of Jupiter's Great Red Spot From JWST/MIRI","authors":"Jake Harkett,&nbsp;Leigh N. Fletcher,&nbsp;Oliver R. T. King,&nbsp;Michael T. Roman,&nbsp;Henrik Melin,&nbsp;Heidi B. Hammel,&nbsp;Ricardo Hueso,&nbsp;Agustín Sánchez-Lavega,&nbsp;Michael H. Wong,&nbsp;Stefanie N. Milam,&nbsp;Glenn S. Orton,&nbsp;Katherine de Kleer,&nbsp;Patrick G. J. Irwin,&nbsp;Imke de Pater,&nbsp;Thierry Fouchet,&nbsp;Pablo Rodríguez-Ovalle,&nbsp;Patrick M. Fry,&nbsp;Mark R. Showalter","doi":"10.1029/2024JE008415","DOIUrl":"https://doi.org/10.1029/2024JE008415","url":null,"abstract":"<p>Jupiter's Great Red Spot (GRS) was mapped by the James Webb Space Telescope (JWST)/Mid-Infrared Instrument (4.9–27.9 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>μ</mi>\u0000 </mrow>\u0000 <annotation> ${upmu }$</annotation>\u0000 </semantics></math>m) in July and August 2022. These observations took place alongside a suite of visual and infrared observations from; Hubble, JWST/NIRCam, Very Large Telescope/VISIR and amateur observers which provided both spatial and temporal context across the jovian disc. The stratospheric temperature structure retrieved using the NEMESIS software revealed a series of hot-spots above the GRS. These could be the consequence of GRS-induced wave activity. In the troposphere, the temperature structure was used to derive the thermal wind structure of the GRS vortex. These winds were only consistent with the independently determined wind field by JWST/NIRCam at 240 mbar if the altitude of the Hubble-derived winds were located around 1,200 mbar, considerably deeper than previously assumed. No enhancement in ammonia was found within the GRS but a link between elevated aerosol and phosphine abundances was observed within this region. North-south asymmetries were observed in the retrieved temperature, ammonia, phosphine and aerosol structure, consistent with the GRS tilting in the north-south direction. Finally, a small storm was captured north-west of the GRS that displayed a considerable excess in retrieved phosphine abundance, suggestive of vigorous convection. Despite this, no ammonia ice was detected in this region. The novelty of JWST required us to develop custom-made software to resolve challenges in calibration of the data. This involved the derivation of the “FLT-5” wavelength calibration solution that has subsequently been integrated into the standard calibration pipeline.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Likely Ferromagnetic Minerals Identified by the Perseverance Rover and Implications for Future Paleomagnetic Analyses of Returned Martian Samples","authors":"Elias N. Mansbach,&nbsp;Tanya V. Kizovski,&nbsp;Eva L. Scheller,&nbsp;Tanja Bosak,&nbsp;Lucia Mandon,&nbsp;Briony Horgan,&nbsp;Roger C. Wiens,&nbsp;Christopher D. K. Herd,&nbsp;Sunanda Sharma,&nbsp;Jeffrey R. Johnson,&nbsp;Travis S. J. Gabriel,&nbsp;Olivier Forni,&nbsp;Yang Liu,&nbsp;Mariek E. Schmidt,&nbsp;Benjamin P. Weiss","doi":"10.1029/2024JE008505","DOIUrl":"https://doi.org/10.1029/2024JE008505","url":null,"abstract":"<p>Although Mars today does not have a core dynamo, magnetizations in the Martian crust and in meteorites suggest a magnetic field was present prior to 3.7 billion years (Ga) ago. However, the lack of ancient, oriented Martian bedrock samples available on Earth has prevented accurate estimates of the dynamo's intensity, lifetime, and direction. Constraining the nature and lifetime of the dynamo are vital to understanding the evolution of the Martian interior and the potential habitability of the planet. The Perseverance rover, which is exploring Jezero crater, is providing an unprecedented opportunity to address this gap by acquiring absolutely oriented bedrock samples with estimated ages from ∼2.3 to &gt;4.1 Ga. As a first step in establishing whether these samples could contain records of Martian paleomagnetism, it is important to determine their ferromagnetic mineralogy, the grain sizes of the phases, and the forms of any natural remanent magnetization. Here, we synthesize data from various Perseverance instruments to achieve those goals and discuss the implications for future laboratory paleomagnetic analyses. Using the rover's instrument payload, we find that cored samples likely contain iron oxides enriched in Cr and Ti. The relative proportions of Fe, Ti, and Cr indicate that the phases may be titanomagnetite or Fe-Ti-Cr spinels that are ferromagnetic at room temperature, but we cannot rule out the presence of non-ferromagnetic ulvöspinel, ilmenite, and chromite due to signal mixing. Importantly, the inferred abundance of iron oxides in the samples suggests that even &lt;1 mm-sized samples will be easily measurable by present-day magnetometers.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008505","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Martian Impact Fracturing Pervasively Influences Habitability","authors":"C. S. Cockell,&nbsp;G. S. Collins,&nbsp;S. Basu,&nbsp;E. Grant,&nbsp;S. McMahon","doi":"10.1029/2023JE008116","DOIUrl":"https://doi.org/10.1029/2023JE008116","url":null,"abstract":"<p>On Mars, the lack of either plate tectonics or a prominent erosional hydrological cycle since the Noachian means geological changes caused by asteroid and comet impact events have been preserved. On Earth, surviving impact-induced fractures are localized to the relatively few preserved craters on the planet. We estimate that the shell of impact-fractured rock on Mars (the “impact-sphere”) could provide between 9,200 times the surface area of a Mars radius sphere and up to 100 times this value, depending on the assumptions made, as potential microbially accessible space. Although &gt;93% of craters we consider are smaller than 10 km in diameter, they contribute only about 5% of the total fracture surface area generated by all craters, making complex craters the dominant process for potential habitat formation. Microbiological data from terrestrial impact craters suggest that these fractures could have significantly enhanced local habitability by providing pathways for fluid flow, and thus nutrients and energy. However, unlike on Earth, the geological history of Mars means that pervasive impact fractures may also have provided pathways for Hesperian and Amazonian brines to infiltrate the subsurface and locally reduce habitability. Combining the fracture data with previous microbiological observations provides testable hypotheses for Martian drilling missions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008116","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomy of a Lunar Silicic Construct—The Wolf Crater Complex, Mare Nubium and Implications for Early Silicic Magmatism on the Moon","authors":"Himela Moitra,&nbsp;Sumit Pathak,&nbsp;Aditya K. Dagar,&nbsp;R. P. Rajasekhar,&nbsp;Satadru Bhattacharya,&nbsp;Moumita Akuria,&nbsp;Saibal Gupta","doi":"10.1029/2023JE008206","DOIUrl":"https://doi.org/10.1029/2023JE008206","url":null,"abstract":"<p>Silicic lithologies on planetary surfaces indicate magmatic evolutionary processes in their interiors. The Wolf crater complex within Mare Nubium on the Moon is one such silicic construct associated with a high thorium anomaly. This study integrates morphological, compositional, chronological and gravity anomaly analyses of high-resolution data from various lunar missions to establish this construct as a silicic volcanic caldera. Lobate flows with steeply sloping fronts indicate that the crater rims comprise high-viscosity silicic lavas, while the structurally controlled inner crater walls suggest caldera collapse triggered by magma depletion. In the crater rims, low Christiansen Feature position values reaffirm the presence of silicic lithologies, consistent with the low gravity anomaly signature beneath the complex, while spectroscopic data reveal low mafic mineral abundances and negligible hydration features. Chronological analyses yield silicic volcanism ages coeval with surrounding mare basalts (3.8–3.6 Ga), while intra-caldera basalts have 2.36–2.02 Ga ages, indicating prolonged magmatism in this region. Melting of suitable crustal protoliths like alkali gabbronorite/monzogabbro/troctolite by basaltic underplating is inferred to have generated silicic magmas that formed the Wolf volcanic complex, instead of basaltic magma fractionation or silicate-liquid immiscibility processes. Large impacts during the Late Heavy Bombardment may have enhanced partial melting of the mantle and created crustal fractures that facilitated the ascent of viscous silicic melts through the lunar crust. Contemporaneous existence of suitable protoliths and adequate crustal pathways for magma ascent may have controlled silicic volcanism on the Moon, and can explain the sporadic occurrence and overlapping ages of the lunar silicic constructs.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008206","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142244775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping and Characterizing the Northern Fan Deposits in Jezero Crater, Mars","authors":"Mohini J. Jodhpurkar,&nbsp;James F. Bell III,&nbsp;Sanjeev Gupta,&nbsp;Briony Horgan,&nbsp;Samantha Gwizd,&nbsp;Gwénaël Caravaca,&nbsp;Nicolas Randazzo","doi":"10.1029/2024JE008308","DOIUrl":"https://doi.org/10.1029/2024JE008308","url":null,"abstract":"<p>The northern inlet channel to Jezero crater (Sava Vallis) terminates in a fan-shaped depositional feature, part of which blends into the separate well-known western fan delta that is the field site for the Mars 2020 mission's <i>Perseverance</i> rover. Jezero's northern fan potentially represents either a second fan delta within the crater or a distal portion of the western fan. To constrain the fluvial and sedimentological history of Jezero and place the rover's in situ observations in proper geologic context, we photogeologically map the northern fan deposits at a larger mapping scale than previous studies, using ground-based imaging from the <i>Perseverance</i> rover for context. Fifteen map units are identified using HiRISE-based interpretations of geologic characteristics and inferred processes as well as crosscutting relative age relationships. Mapped units are also defined based on orbital data from CRISM and THEMIS to assess their compositional signatures. We interpret the northern fan deposits as older than the uppermost blocky unit in the western fan delta, suggesting that they were deposited contemporaneously with or prior to the deposition of the western fan, and under similar climate conditions. The eastern portion of the northern fan deposits shows evidence of fluvial deposition from Sava Vallis, while part of its western side could represent a distal part of the western fan delta. We synthesize our interpretations to present scenarios for the deposition of the northern and western fans, which can help constrain the history of both watersheds and place it into context within the broader Isidis basin region.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ferric Iron Evolution During Crystallization of the Earth and Mars","authors":"Laura Schaefer,&nbsp;Kaveh Pahlevan,&nbsp;Linda T. Elkins-Tanton","doi":"10.1029/2023JE008262","DOIUrl":"https://doi.org/10.1029/2023JE008262","url":null,"abstract":"<p>Magma ocean crystallization models that track <i>f</i>O₂ evolution can reproduce the D/H ratios of both the Earth and Mars without the need for exogenous processes. Fractional crystallization leads to compositional evolution of the bulk oxide components. Recent work suggests that metal-saturated magma oceans may contain near-present-day Fe³⁺ concentrations. We model the fractional crystallization of Earth and Mars, including Fe²⁺ and Fe³⁺ as separate components. We calculate Fe³⁺ partition coefficients for lower mantle minerals and compare the results of fractional crystallization for both Earth and Mars. We calculate oxygen fugacity (<i>f</i>O₂) at the surface as the systems evolve and compare them to constraints on the <i>f</i>O₂ of the last magma ocean atmosphere from D/H ratios, both with and without metal saturation. For Earth, we find that Fe³⁺ likely behaves incompatibly in the lower mantle in order to match the D/H constraint for whole mantle models, but shallow magma ocean models also provide reasonable matches. Disproportionation in whole mantle magma oceans likely overpredicts the amount of Fe³⁺ and metal that form or require subsequent reduction to return to present-day values. For Mars, we cannot match the D/H constraints on last <i>f</i>O₂ unless the magma ocean begins with &lt;50% of the predicted Fe³⁺, but better match the present day mantle redox. We show that Fe³⁺ partitioning has a measurable effect on magma ocean redox, and that it evolves throughout the magma ocean's lifetime. We highlight the need for additional experimental constraints on ferric iron mineral/melt partitioning and more thermodynamic data for the Fe-disproportionation reaction.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the Cessation of Convection in Mercury's Mantle","authors":"C. Jain,&nbsp;V. S. Solomatov","doi":"10.1029/2024JE008365","DOIUrl":"https://doi.org/10.1029/2024JE008365","url":null,"abstract":"<p>The question of whether the present-day mantle of Mercury is undergoing convection remains unresolved. We address this issue by estimating the minimum value of the core-mantle boundary (CMB) temperature needed to support mantle convection and considering the time required to cool the mantle below this threshold. A simple mathematical analysis of the cooling of the core, based on the assumption of a quasi-steady-state thermal equilibrium of Mercury's mantle, shows that the CMB temperature falls to the critical temperature for cessation of convection roughly halfway through the planet's evolutionary history. To first order, the duration of subsolidus convection does not depend on the absolute value of the viscosity. It depends primarily on parameters that control the viscosity function, such as the stress exponent and the activation energy. Our results based on conventional assumptions suggest the absence of present-day mantle convection in Mercury, which is consistent with numerical models of Mercury's thermal history. However, because of large uncertainties in the controlling parameters, the possibility of still ongoing mantle convection on Mercury cannot be ruled out.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deterministic Model for Asteroid Thermal Evolution With Fragmentation and Reassembly Into a Gravitational Aggregate","authors":"J. Ren,&nbsp;M. A. Hesse,&nbsp;N. Dygert,&nbsp;M. P. Lucas","doi":"10.1029/2023JE007898","DOIUrl":"https://doi.org/10.1029/2023JE007898","url":null,"abstract":"<p>We present a model for the thermal evolution of asteroids that experience catastrophic fragmentation and reassembly into a gravitational aggregate. The three stage model comprises the initial radiogenic heating, fragmentation and cooling, and reassembly into a porous gravitational aggregate. The heat loss during catastrophic fragmentation is largely determined by the production of small particles that equilibrate thermally with ambient space. To determine this heat loss we combine a power-law for the cumulative fragment mass distribution with analytic solutions for conductive cooling. To keep the model deterministic we fragment the parent body and reassemble the gravitational aggregate in shells ordered in decreasing volume. We use the resulting model to show that catastrophic fragmentation can lead to significant heat loss despite the short reassembly times (e.g., <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≤</mo>\u0000 </mrow>\u0000 <annotation> ${le} $</annotation>\u0000 </semantics></math>1 year), due to the production of many small fragments. Despite the heat loss during fragmentation, the reassembled gravitational aggregate will retain more heat than the undisturbed parent body in the long term, due to the formation of an insulating megaregolith. Applied to the H-chondrite parent body, our model can reproduce both the fast cooling rates at high temperatures and slow cooling rates at low temperature.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}