Planetary and Space Science最新文献

{"title":"A sliding window method considering image shadow to detect Mars rock from MRO HiRISE datasets","authors":"Na Sun ,&nbsp;Yongjiu Feng ,&nbsp;Xiaohua Tong ,&nbsp;Pengshuo Li ,&nbsp;Rong Wang ,&nbsp;Yuhao Wang ,&nbsp;Yuze Cao ,&nbsp;Zilong Cao ,&nbsp;Xiong Xu ,&nbsp;Yusheng Xu ,&nbsp;Shijie Liu","doi":"10.1016/j.pss.2025.106155","DOIUrl":"10.1016/j.pss.2025.106155","url":null,"abstract":"<div><div>Rock distribution is a crucial factor in landing site selection for Mars exploration. Typically, rocks in flat Martian terrains are characterized by clear boundaries and distinct shadows. We developed a new method (named SSW-ROCK) for rock detection from HiRISE images using the shadow (S) and sliding window technique (SW). SSW-ROCK uses shadows to define the minimum bounding rectangle in the direction of illumination, establishing an initial sliding window based on this rectangle. The window is then slid to the termination position according to the predefined conditions. The rock size can be obtained by fitting the ellipse with the positions of the initial and termination windows. The rock height is estimated using the shadow length along the illumination direction. We used five HiRISE images of Mars between 65° N −70° N for rock detection and detected 532,284 rocks with maximum diameters &gt;1.5 m. We selected accuracy assessment areas in each of the five images and extracted the rocks manually. The SSW-ROCK results were assessed for accuracy using the manual results as a benchmark. In the assessment, we proposed two evaluation metrics, PS and PM: PS measures the proportion of SSW-ROCK results with center points within the range of manual results, while PM measures the proportion of manual results with center points within the range of SSW-ROCK results. Accuracy assessments in five selected areas showed that the mean for both PS and PM exceeded 77 %. Additionally, the dimensions detected by the SSW-ROCK method for known Mars landers closely match their actual sizes. These experiments demonstrate that the SSW-ROCK method is effective for rock detection in flat Martian terrains.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"265 ","pages":"Article 106155"},"PeriodicalIF":1.8,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"He+ ions in the vicinity of mercury observed by the MESSENGER and BepiColombo spacecraft","authors":"Markus Fränz ,&nbsp;Harald Krüger ,&nbsp;Jim M. Raines ,&nbsp;Austin N. Glass ,&nbsp;Daniel J. Gershman ,&nbsp;Fabio Prencipe ,&nbsp;Norbert Krupp ,&nbsp;Lina Z. Hadid ,&nbsp;Dominique Delcourt ,&nbsp;Sae Aizawa ,&nbsp;Shoichiro Yokota ,&nbsp;Yuki Harada ,&nbsp;Yoshifumi Saito","doi":"10.1016/j.pss.2025.106152","DOIUrl":"10.1016/j.pss.2025.106152","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was launched in 2004, and between March 2011 and April 2015 it was the first spacecraft in orbit around Mercury. The Fast Imaging Plasma Spectrometer (FIPS) instrument on board MESSENGER measured the ion composition in the vicinity of Mercury and in the inner solar system.&lt;/div&gt;&lt;div&gt;We aim to determine the origin of He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; ions in the inner solar system and in the environment of Mercury, continuing earlier work by Gershman et al., (2013).&lt;/div&gt;&lt;div&gt;We have analyzed measurements of He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; ions made by the FIPS instrument during the interplanetary cruise phase of MESSENGER and its entire orbital mission at Mercury. We determined the spatial distributions of He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; ions in the regions sampled by MESSENGER during that period and compare the spectra to a similar observation by the Mass Spectrum Analyzer instrument which is part of the Mercury Plasma Particle Experiment (MPPE-MSA) onboard BepiColombo. We consider two possible sources of He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;: (1) interstellar neutral helium ionized close to Mercury and (2) solar He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; ions converted close to or at the surface of Mercury. We also compare the observed densities with a simple model of the ionization of the interstellar helium flow.&lt;/div&gt;&lt;div&gt;The FIPS data show a continuous evolution of the He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; energy spectra from solar wind towards Mercury - changing from a shape typical for pick-up ions to a thermalized spectrum. This could mean that interstellar He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; is concentrated at Mercury by increased electron impact ionization close to the planet. We find a remarkably similar high mean ratio of He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;/He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; ions in the upstream solar wind and in the inner magnetosphere, while the ratio is reduced in the magnetosheath.&lt;/div&gt;&lt;div&gt;Outside Mercury’s magnetosphere the source of He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; ions is interstellar helium, while inside the planet’s magnetosheath and the magnetosphere both interstellar helium and solar wind helium may be of similar magnitude. The observed median upstream He&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; densities are in good quantitative agreement with a si","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"265 ","pages":"Article 106152"},"PeriodicalIF":1.8,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 simulator of the MAJIS instrument onboard the JUICE mission: Description and application to operational and scientific cases","authors":"C. Royer ,&nbsp;P. Haffoud ,&nbsp;Y. Langevin ,&nbsp;F. Poulet ,&nbsp;D. Bockelée-Morvan ,&nbsp;E. D’Aversa ,&nbsp;M. Cisneros-González ,&nbsp;D. Grassi ,&nbsp;N. Ligier ,&nbsp;G. Piccioni ,&nbsp;J. Carter ,&nbsp;F. Tosi ,&nbsp;M. Vincendon ,&nbsp;F. Zambon ,&nbsp;V. Zakharov ,&nbsp;M. Gilles ,&nbsp;B. Seignovert","doi":"10.1016/j.pss.2025.106147","DOIUrl":"10.1016/j.pss.2025.106147","url":null,"abstract":"<div><div>The MAJIS (Moons And Jupiter Imaging Spectrometer) instrument, part of the JUICE (JUpiter ICy moons Explorer) mission, is a crucial tool for investigating the composition and dynamics of Jupiter’s atmosphere, and the surfaces and exospheres of its icy moons. To optimize observational planning and assess instrument performance, we have developed a radiometric simulator that accurately models MAJIS expected signal from various Jovian system targets. This simulator incorporates instrumental parameters, the spacecraft trajectory, observational constraints, and Jupiter’s radiation environment. It provides essential outputs, including Signal-to-Noise Ratio (SNR) predictions and optimized instrument settings for different observational scenarios. By simulating both radiometric performance and de-spiking strategies to mitigate the impact of Jupiter radiation belt, the tool aids in refining observation strategies throughout the MAJIS operations. Several scientific applications demonstrate the simulator capabilities, from mapping the surfaces of Ganymede and Europa to detecting exospheric emissions and atmospheric composition on Jupiter. This simulator is a critical asset for maximizing MAJIS scientific return and ensuring optimal data acquisition during MAJIS exploration of the Jovian system. Study cases are presented for illustrating the capability of the simulator to model scenarios such as high-resolution mapping of Ganymede, exosphere characterization and hotspot detection on Io and Europa. These simulations confirm the potential of MAJIS for detecting key spectral features with high signal to noise ratio so as to provide major contributions to the main goals of the mission: habitability and compositional diversity in the Jovian system.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"264 ","pages":"Article 106147"},"PeriodicalIF":1.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Stability of adenine in interaction with saponite in a simulated hydrothermal impact-generated system and its implications for astrobiology","authors":"L. Ramírez-Vázquez ,&nbsp;A.A. Duarte-Ruiz ,&nbsp;M.G. Santiago-Santos ,&nbsp;G. Cordero Tercero ,&nbsp;J.A. Cruz-Castañeda","doi":"10.1016/j.pss.2025.106151","DOIUrl":"10.1016/j.pss.2025.106151","url":null,"abstract":"<div><div>For astrobiological studies related to the chemical evolution of organic molecules, it is essential to establish a plausible geological context, either on early Earth or at another viable site within the solar system. Impact-generated hydrothermal systems may have provided an ideal environment for prebiotic chemical reactions before the origin of life.</div><div>In this study, we simulated the conditions of such systems using saponite, a clay mineral identified as a product of hydrothermal alteration in impact craters that once hosted hydrothermal activity. Adenine was chosen as the model organic molecule due to its biological relevance and its known abiotic formation, as evidenced by its detection in certain meteorites. The interaction between saponite and adenine was investigated by analyzing adsorption kinetics and isotherms, revealing that adsorption is favored at acidic pH (3.5), as under these conditions, approximately 97 % of the adenine is adsorbed. The interaction between the molecule and the clay was observed through spectroscopic techniques such as XRD, FRX, Raman and ATR-FTIR, UV–vis spectrophotometry, and HPLC-UV chromatographic. Additionally, thermolysis experiments were conducted on aqueous adenine solutions and adenine-saponite mixtures. The results indicate that saponite plays a protective role, preventing adenine decomposition at temperatures ranging from 100 °C to 200 °C across a pH range of 3.5–8.9. These processes are critical for astrobiology, as they demonstrate how some clay minerals could have concentrated and preserved prebiotic organic molecules on early Earth, Mars, or planetesimals, facilitating the emergence of life.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"264 ","pages":"Article 106151"},"PeriodicalIF":1.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 insights into the origin of ice: chronological implication from 14 permanently shadowed craters on Mercury","authors":"S. Bertoli ,&nbsp;E. Martellato ,&nbsp;G. Cremonese ,&nbsp;M. Massironi ,&nbsp;A. Lucchetti ,&nbsp;M. Pajola ,&nbsp;P. Borin ,&nbsp;P. Cambianica ,&nbsp;E. Simioni","doi":"10.1016/j.pss.2025.106150","DOIUrl":"10.1016/j.pss.2025.106150","url":null,"abstract":"<div><div>The polar regions of Mercury are characterised by areas known as permanently shadowed regions (PSRs), which provide stable thermal conditions for water ice over geological timescales. Both Earth-based radar measurements and data from the NASA/MESSENGER spacecraft identified the area encompassing the PSRs with reflectance properties indicative of both water ice and other volatiles.</div><div>In this work, we employ crater counting absolute model age determination on both ejecta and crater floor materials of fourteen northern polar craters yielding cold traps and ice. Our findings unravel younger ages for the floors than for the associated ejecta, prompting further investigation into the role of ice as the mechanisms responsible for rejuvenating polar crater floors. Notably, a correlation emerges between the age of craters and the accumulation of ice within PSRs. Indeed, older craters tend to accumulate more ice within the PSRs, measured in terms of area. These correlations may be attributed to the two primary processes allowing ice continuous accumulation: micrometeorite flux and solar wind implantation. Considering the limiting factors for these processes, which are impact velocity and gardening, respectively, it is estimated that over approximately 3.7 billion years (the age of the oldest craters in this study), a substantial amount of ice would have accumulated at the poles. Two of the analyzed craters do not follow the trend and this might signify episodic delivery of ice resulting from asteroidal and/or cometary impacts. Thus, we propose that both steady-state accumulation and episodic delivery processes should be considered when analyzing the presence of ice in PSRs.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"264 ","pages":"Article 106150"},"PeriodicalIF":1.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Comparative analysis of mask R-CNN and U-Net architectures using ResNet as backbone for lunar crater detection","authors":"Mimansa Sinha ,&nbsp;Sanchita Paul ,&nbsp;Mili Ghosh Nee Lala","doi":"10.1016/j.pss.2025.106140","DOIUrl":"10.1016/j.pss.2025.106140","url":null,"abstract":"<div><div>Automated detection of lunar craters is crucial for advancing planetary science, enabling efficient geological mapping, surface age estimation, and resource identification. This study compares Mask R-CNN (instance segmentation) and U-Net (semantic segmentation) architectures using ResNet as the backbone for lunar crater detection. Key novelty is comparing model performance in both a Geospatial context (ArcGIS Pro environment) and non-Geospatial environment a method not heretofore attempted. Training and validation were conducted using Geocoded Chandrayaan-2 TMC-2 DEM data, employing a new strategy that facilitates accurate localization and precise detection of small, morphologically complex craters. Mask R-CNN achieved a precision of 91 %, a recall of 85 %, and an Intersection over Union (IoU) of 87 %, excelling in detecting intricate crater edges and identifying crater diameters with accurate geolocation information. However, it struggled to detect craters with less depth or degraded rims. Conversely, U-Net demonstrated superior recall (93 %) but moderate precision (85 %), making it efficient for broader crater localization tasks. U-Net excelled at identifying perfectly shaped craters but faced challenges in detecting larger and very small craters. Mask R-CNN identified previously uncatalogued craters, particularly those smaller than 1 km in diameter, while U-Net excelled at detecting a greater number of overlapping and nested craters, showcasing their complementary strengths. These findings underscore the potential of deep learning to enhance lunar research and future planetary exploration.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"264 ","pages":"Article 106140"},"PeriodicalIF":1.8,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Dynamical regimes of two eccentric and mutually inclined giant planets","authors":"Tabare Gallardo,&nbsp;Alfredo Suescun","doi":"10.1016/j.pss.2025.106137","DOIUrl":"10.1016/j.pss.2025.106137","url":null,"abstract":"<div><div>We consider a basic planetary system composed by a Sun like star, a Jupiter-like planet and a Neptune-like planet in a wide range of orbital configurations not limited to the hierarchical case. We present atlases of resonances showing the domains of <span><math><mo>∼</mo></math></span> <span><math><mrow><mn>1300</mn></mrow></math></span> mutual mean-motion resonances (MMRs) and their link to chaotic and regular dynamics. Following a semi-analytical method for the study of the secular dynamics we found two regimes for equilibrium configurations: one for low mutual inclinations were equilibrium is related to oscillations of <span><math><mrow><mi>Δ</mi><mi>ϖ</mi></mrow></math></span> around <span><math><mrow><mn>0</mn><mo>°</mo></mrow></math></span> or <span><math><mrow><mn>180</mn><mo>°</mo></mrow></math></span>, and other for high mutual inclinations where the equilibrium is given by defined values of the <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> equal to integer multiples of <span><math><mrow><mn>90</mn><mo>°</mo></mrow></math></span>. By numerical integration of the full equations of motion we calculate the fundamental frequencies of the systems in their diverse configurations and study their dependence with the orbital elements. According to the analysis of the fundamental frequencies we found two dynamical regimes depending on the initial mutual inclination and the limit between the two regimes occurs at some critical inclination <span><math><mrow><mn>30</mn><mo>°</mo><mo>≲</mo><msub><mrow><mi>i</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>≲</mo><mn>40</mn><mo>°</mo></mrow></math></span> defined by the occurrence of the secular resonance <span><math><mrow><msub><mrow><mi>g</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><msub><mrow><mi>g</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>. For <span><math><mrow><mi>i</mi><mo>&lt;</mo><msub><mrow><mi>i</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> the dynamics is analogue to the classic secular model for low <span><math><mrow><mo>(</mo><mi>e</mi><mo>,</mo><mi>i</mi><mo>)</mo></mrow></math></span> with well defined three fundamental frequencies and free and forced modes, conserving quasi constant the mutual inclination. For <span><math><mrow><mi>i</mi><mo>&gt;</mo><msub><mrow><mi>i</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> the dynamics is completely different with increasing changes in mutual inclination and emerging combinations of the fundamental frequencies and, depending on the case, dominated by the secular resonance or the vZLK mechanism.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"263 ","pages":"Article 106137"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Using imagery from the Mars Science Laboratory mission to understand wind properties of aerosols aloft","authors":"C.L. Campbell ,&nbsp;J.E. Moores","doi":"10.1016/j.pss.2025.106119","DOIUrl":"10.1016/j.pss.2025.106119","url":null,"abstract":"<div><div>Since landing in 2012, the Mars Science Laboratory (MSL, Curiosity) has been investigating local aerosols through atmospheric imagery taken by its onboard Navigation Cameras (NCAMs). In particular, a Zenith Movie (ZM), is a vertically pointed 8-frame movie that is used to classify meteorological wind direction based on aerosol movement within the frames. Several Mars Year (MY) worth of data have been analysed and found repeatable wind directions year-to-year. Water-ice clouds in the Aphelion season had strong Easterly winds, which agrees with modelling that shows a strong cross-equatorial Hadley cell in this season. The Perihelion season did not show any strong directions, which was attributed to the chaotic motion seen in dust clouds expected during this season. When compared to the Rover Environmental Monitoring Station (REMS) onboard MSL, wind directions from the ZMs did not agree with REMS results. This mismatch between REMS and ZM wind results indicates that aerosols observed in imagery are most likely well above the crater rather than at the surface where REMS is located.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"263 ","pages":"Article 106119"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Sealing Europa’s vents by vapor deposition: An order-of-magnitude study","authors":"S. Boccelli ,&nbsp;S.R. Carberry Mogan ,&nbsp;R.E. Johnson ,&nbsp;O.J. Tucker","doi":"10.1016/j.pss.2025.106136","DOIUrl":"10.1016/j.pss.2025.106136","url":null,"abstract":"<div><div>Fractures and vents in the ice crust of Europa, exposing the sub-surface ocean or liquid–water inclusions to the vacuum, might be responsible for the generation of water-vapor plumes. During its passage through the ice, the plume vapor is expected to partially condense on the cold ice walls. Together with other effects (water spillage, compression forces, etc.) this mechanism likely contributes to sealing the vent. In this work, we develop a simple lumped-parameter model that can quantify how quickly a hypothetical vent of prescribed width would be sealed via water-vapor deposition. As an example, we apply our model to the vent size and density conditions inferred from the 2012 Hubble Space Telescope plume detection, predicting a sealing time of about 30 min. This suggests that the actual ice fracture might have been larger than originally proposed and/or the plume density at the vent might have been lower. While many other effects could have been present and responsible for sealing the vent, our estimates indicate that vapor deposition might have played a major role in eventually shutting off the observed plume. A map of sealing times vs. plume density, mass flow rate and aperture areas is given. Plume quantities from the literature are analyzed and compared to our results. For a given plume density/mass flow rate, small apertures would be sealed quickly by vapor deposition and are thus incompatible with observations.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"263 ","pages":"Article 106136"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"High-resolution rock abundance derivation of lunar cold spot craters based on RA-SAR model","authors":"Jiacheng Sun ,&nbsp;Xin Lu ,&nbsp;Gaofeng Shu ,&nbsp;Zhengwei Guo ,&nbsp;Ning Li","doi":"10.1016/j.pss.2025.106138","DOIUrl":"10.1016/j.pss.2025.106138","url":null,"abstract":"<div><div>The distribution of rock abundance (RA) on the lunar surface plays a pivotal role in understanding its geological evolution. This study focuses on the derivation of high-resolution RA data for lunar cold spot craters using Mini-RF (Miniature Radio Frequency) synthetic aperture radar (SAR) data. Firstly, terrain correction was applied to the SAR data. Secondly, the correlation between the Stokes parameters (<span><math><mrow><msub><mi>S</mi><mn>1</mn></msub></mrow></math></span>, <span><math><mrow><msub><mi>S</mi><mn>2</mn></msub></mrow></math></span>, <span><math><mrow><msub><mi>S</mi><mn>3</mn></msub></mrow></math></span>, and <span><math><mrow><msub><mi>S</mi><mn>4</mn></msub></mrow></math></span>) and RA was examined using optically-derived RA data, which aligns with the resolution of the Mini-RF SAR images. By plotting scatter diagrams showing the relationships between the Stokes parameters and the optically-derived RA, strong statistical associations were established. Finally, based on these findings, we formulated a regression-based RA-SAR model. This model was applied to other lunar cold spot craters in order to derive their high-resolution RA distributions. The experimental results show that the model yields highly precise outcomes when validated against both Diviner RA and optical data. The study provides a new approach for inferring rock distribution across the lunar surface using SAR data, and offers valuable insights for advancing lunar geological research.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"263 ","pages":"Article 106138"},"PeriodicalIF":1.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}