Pub Date : 2025-06-06DOI: 10.1016/j.pss.2025.106151
L. Ramírez-Vázquez , A.A. Duarte-Ruiz , M.G. Santiago-Santos , G. Cordero Tercero , J.A. Cruz-Castañeda
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.
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.
{"title":"Stability of adenine in interaction with saponite in a simulated hydrothermal impact-generated system and its implications for astrobiology","authors":"L. Ramírez-Vázquez , A.A. Duarte-Ruiz , M.G. Santiago-Santos , G. Cordero Tercero , 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":"2025-06-06","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}
Pub Date : 2025-06-06DOI: 10.1016/j.pss.2025.106150
S. Bertoli , E. Martellato , G. Cremonese , M. Massironi , A. Lucchetti , M. Pajola , P. Borin , P. Cambianica , E. Simioni
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.
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.
{"title":"New insights into the origin of ice: chronological implication from 14 permanently shadowed craters on Mercury","authors":"S. Bertoli , E. Martellato , G. Cremonese , M. Massironi , A. Lucchetti , M. Pajola , P. Borin , P. Cambianica , 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":"2025-06-06","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}
Pub Date : 2025-05-28DOI: 10.1016/j.pss.2025.106140
Mimansa Sinha , Sanchita Paul , Mili Ghosh Nee Lala
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.
{"title":"Comparative analysis of mask R-CNN and U-Net architectures using ResNet as backbone for lunar crater detection","authors":"Mimansa Sinha , Sanchita Paul , 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":"2025-05-28","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}
Pub Date : 2025-05-21DOI: 10.1016/j.pss.2025.106138
Jiacheng Sun , Xin Lu , Gaofeng Shu , Zhengwei Guo , Ning Li
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 (, , , and ) 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.
月球表面岩石丰度分布对了解月球地质演化具有重要意义。本研究主要利用Mini-RF （Miniature Radio Frequency）合成孔径雷达（SAR）数据推导月球冷斑陨石坑的高分辨率RA数据。首先，对SAR数据进行地形校正。其次，利用与Mini-RF SAR图像分辨率一致的光学衍生RA数据，研究Stokes参数（S1、S2、S3和S4）与RA之间的相关性。通过绘制散点图显示Stokes参数与光学衍生RA之间的关系，建立了很强的统计关联。最后，在此基础上，建立了基于回归的RA-SAR模型。该模型被应用于其他月球冷点陨石坑，以获得它们的高分辨率RA分布。实验结果表明，该模型对Diviner RA和光学数据进行了验证，结果精度很高。该研究为利用SAR数据推断月球表面岩石分布提供了一种新的方法，并为推进月球地质研究提供了有价值的见解。
{"title":"High-resolution rock abundance derivation of lunar cold spot craters based on RA-SAR model","authors":"Jiacheng Sun , Xin Lu , Gaofeng Shu , Zhengwei Guo , 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":"2025-05-21","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}
Pub Date : 2025-05-20DOI: 10.1016/j.pss.2025.106137
Tabare Gallardo, Alfredo Suescun
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 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 around or , and other for high mutual inclinations where the equilibrium is given by defined values of the equal to integer multiples of . 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 defined by the occurrence of the secular resonance . For the dynamics is analogue to the classic secular model for low with well defined three fundamental frequencies and free and forced modes, conserving quasi constant the mutual inclination. For 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.
我们考虑一个基本的行星系统，由一个类似太阳的恒星，一个类似木星的行星和一个类似海王星的行星组成，在广泛的轨道配置中，不限于分层情况。我们展示了共振图谱，显示了~ 1300个互平均运动共振（MMRs）域及其与混沌和规则动力学的联系。根据长期动力学研究的半解析方法，我们发现了平衡配置的两种制度：一种是低互倾角，平衡与Δϖ在0°或180°附近的振荡有关，另一种是高互倾角，其中平衡由ωi等于90°的整数倍的定义值给出。通过对整个运动方程的数值积分，我们计算了系统在不同构型下的基频，并研究了它们与轨道元的关系。根据基频分析，我们发现了两种依赖于初始相互倾角的动力状态，两种状态之间的极限出现在某个临界倾角30°> ic > 40°处，该临界倾角由长期共振g1=g2的出现所定义。对于i<；ic，动力学类似于低（e,i）的经典长期模型，具有定义良好的三个基频和自由模态和强迫模态，保持相互倾斜度准常数。对于i>；ic，随着相互倾斜度变化的增加和基频组合的出现，动力学完全不同，并且根据情况，由长期共振或vZLK机制主导。
{"title":"Dynamical regimes of two eccentric and mutually inclined giant planets","authors":"Tabare Gallardo, 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><</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>></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":"2025-05-20","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}
Pub Date : 2025-05-16DOI: 10.1016/j.pss.2025.106136
S. Boccelli , S.R. Carberry Mogan , R.E. Johnson , O.J. Tucker
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.
{"title":"Sealing Europa’s vents by vapor deposition: An order-of-magnitude study","authors":"S. Boccelli , S.R. Carberry Mogan , R.E. Johnson , 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":"2025-05-16","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}
Pub Date : 2025-05-15DOI: 10.1016/j.pss.2025.106129
Jayanth Chennamangalam , Paul Brook , Martin Elvis , Samuel Peterson
We modify the probabilistic formalism developed by Elvis (2014) to estimate the number of lunar craters that contain ore-bearing asteroid remnants. When we consider craters at or above a threshold diameter of 1 km, we estimate an upper limit of craters with asteroid remnants containing significant amounts of platinum group metals and an upper limit of craters with asteroid remnants that contain significant amounts of water in the form of hydrated minerals. For a more conservative threshold of 5 km, we estimate craters with asteroid remnants that contain significant amounts of platinum group metals. These values are one to two orders of magnitude larger than the number of ore-bearing near-Earth asteroids estimated by Elvis (2014), implying that it may be more advantageous, and hence more profitable, to mine asteroids that have impacted the Moon rather than the ones that are in orbit.
{"title":"On ore-bearing asteroid remnants in lunar craters","authors":"Jayanth Chennamangalam , Paul Brook , Martin Elvis , Samuel Peterson","doi":"10.1016/j.pss.2025.106129","DOIUrl":"10.1016/j.pss.2025.106129","url":null,"abstract":"<div><div>We modify the probabilistic formalism developed by Elvis (2014) to estimate the number of lunar craters that contain ore-bearing asteroid remnants. When we consider craters at or above a threshold diameter of 1<!--> <!-->km, we estimate an upper limit of <span><math><mrow><mo>∼</mo><mn>6</mn><mo>,</mo><mn>500</mn></mrow></math></span> craters with asteroid remnants containing significant amounts of platinum group metals and an upper limit of <span><math><mrow><mo>∼</mo><mn>3</mn><mo>,</mo><mn>400</mn></mrow></math></span> craters with asteroid remnants that contain significant amounts of water in the form of hydrated minerals. For a more conservative threshold of 5<!--> <!-->km, we estimate <span><math><mrow><mo>≲</mo><mn>400</mn></mrow></math></span> craters with asteroid remnants that contain significant amounts of platinum group metals. These values are one to two orders of magnitude larger than the number of ore-bearing near-Earth asteroids estimated by Elvis (2014), implying that it may be more advantageous, and hence more profitable, to mine asteroids that have impacted the Moon rather than the ones that are in orbit.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"263 ","pages":"Article 106129"},"PeriodicalIF":1.8,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090097","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}
Upcoming missions to the Moon represent new science opportunities and challenges. The electrostatic nature of the regolith combined with the solar wind makes it loft and adhere to almost any surface, which represents a threat for future manned and robotic missions. Understanding the charge state of the lunar soil under a representative environment is a key step towards ensuring safe lunar missions. While the global first order effect of exposure to the Sun's UV is to charge the soil positively, past experiments suggested that the transported dusts could be charged negatively. This counter-intuitive behavior was then supported by modeling, which explained the existence of negative charges but also predicted that of positively charged ones. To investigate the charging behavior of dust under a representative environment, we developed an experimental protocol based on a polarized sensitive sensor dedicated to the charge measurement of single dust grains with an accuracy of about 1 fC. The first set of measurements obtained with JSC-1A lunar dust simulants in high vacuum reveals the bipolar nature of lunar dust net charge in the regolith when exposed to UVs. Indeed, both positive and negative dusts were detected, supporting the complexity of the regolith charging processes suggested by the models.
{"title":"Measurement of bipolar charge distribution of lunar dust simulant under VUV irradiation","authors":"Rémi Pacaud , Jean-Charles Matéo-Vélez , Sébastien Hess , Sylvain Ranvier","doi":"10.1016/j.pss.2025.106120","DOIUrl":"10.1016/j.pss.2025.106120","url":null,"abstract":"<div><div>Upcoming missions to the Moon represent new science opportunities and challenges. The electrostatic nature of the regolith combined with the solar wind makes it loft and adhere to almost any surface, which represents a threat for future manned and robotic missions. Understanding the charge state of the lunar soil under a representative environment is a key step towards ensuring safe lunar missions. While the global first order effect of exposure to the Sun's UV is to charge the soil positively, past experiments suggested that the transported dusts could be charged negatively. This counter-intuitive behavior was then supported by modeling, which explained the existence of negative charges but also predicted that of positively charged ones. To investigate the charging behavior of dust under a representative environment, we developed an experimental protocol based on a polarized sensitive sensor dedicated to the charge measurement of single dust grains with an accuracy of about 1 fC. The first set of measurements obtained with JSC-1A lunar dust simulants in high vacuum reveals the bipolar nature of lunar dust net charge in the regolith when exposed to UVs. Indeed, both positive and negative dusts were detected, supporting the complexity of the regolith charging processes suggested by the models.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"263 ","pages":"Article 106120"},"PeriodicalIF":1.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943182","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}
Pub Date : 2025-05-02DOI: 10.1016/j.pss.2025.106119
C.L. Campbell , J.E. Moores
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.
自2012年登陆火星以来，火星科学实验室（MSL，好奇号）一直在通过其机载导航相机（NCAMs）拍摄的大气图像调查当地的气溶胶。特别是，Zenith Movie （ZM）是一个垂直指向的8帧Movie，用于根据帧内的气溶胶运动来分类气象风向。对几个火星年（MY）的数据进行了分析，发现每年都有可重复的风向。远日点季节的水冰云有很强的东风，这与模型显示的这个季节有很强的横跨赤道的哈德利环流相一致。近日点季节没有显示出任何强烈的方向，这归因于在这个季节预计会出现的尘埃云的混乱运动。当与MSL上的漫游者环境监测站（REMS）进行比较时，来自ZMs的风向与REMS的结果不一致。REMS和ZM风结果之间的不匹配表明，在图像中观察到的气溶胶很可能在陨石坑上方，而不是在REMS所在的表面。
{"title":"Using imagery from the Mars Science Laboratory mission to understand wind properties of aerosols aloft","authors":"C.L. Campbell , 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":"2025-05-02","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}
Pub Date : 2025-04-25DOI: 10.1016/j.pss.2025.106128
A. Szilágyi-Sándor, B. Székely
One of the unique valleys in the southern hemisphere of Mars is the 700 km long Nirgal Vallis. The catchment area of the river-like valley, presumably formed in the Hesperian period (3000–3700 Ma ago), has been shaped over time by many influences. The goal of this study is to explore and separate these potential influences including changes in the water level of the Uzboi Vallis, its erosion base. The other aim is to detect and describe the effects of tectonic processes for we have found potential evidence. Our working hypothesis is that Nirgal Vallis was once a river valley: our study analyses this possibility. The climate of Mars has undergone drastic changes in the past, and liquid water is currently not stable on the surface. The formation of former river valleys after the active wet period continued, including Nirgal Vallis. Morphometric techniques were applied based on MOLA, THEMIS, and HiRISE data. The topography of the Nirgal Vallis have been analyzed by swath analysis, calculation of various geomorphometric parameters, and runoff model. HiRISE digital terrain models having decimeter-scale resolution derived from the HiRISE stereopairs have been used for the detailed analysis.
A subdivision of the Nirgal Vallis according to its tectonic geomorphological structures was established. The swath analysis and the runoff model calculation show that, although the valley does not have a strict thalweg today, i.e., water currently cannot flow down it, the valley does have a trend of slope along the whole length and even intermittent slope changes can be observed along the whole valley. Several small-scale morphological features were also identified using MOLA data.
We conclude that the tectonic processes have transformed the morphology of the riverbed: it is divided into small sections (closed basins) so that currently water would not be able to flow down in it. Extraterrestrial (i.e. effects from outside Mars) causes on Mars also influence this, i.e. the formation of larger and smaller craters has also left its mark on the topography. We interpret the subperpendicular elongated morphological features on the plateau surrounding Nirgal Vallis as wrinkle ridges: their size, shape and spacing is similar to those identified by previous authors elsewhere. We also found evidence that the valley bottom has also been modified by the processes that formed the wrinkle ridges. Our observations imply younger tectonic influence of the area, presumably, postdating the fluvial erosional regime.
The Luki Crater, located near the confluence of Nirgal Vallis and Uzboi Vallis, has also been analyzed, and evidence has been found to be tectonically modified. This modification is in congruence with the results of other analyses indicating tectonic influence of Nirgal Vallis. Our results may also have implications for formation of the Uzboi Vallis, though this will require further studies.
{"title":"The evolution of Nirgal Vallis (Mars) based on morphometric results: does tectonics play a role?","authors":"A. Szilágyi-Sándor, B. Székely","doi":"10.1016/j.pss.2025.106128","DOIUrl":"10.1016/j.pss.2025.106128","url":null,"abstract":"<div><div>One of the unique valleys in the southern hemisphere of Mars is the 700 km long Nirgal Vallis. The catchment area of the river-like valley, presumably formed in the Hesperian period (3000–3700 Ma ago), has been shaped over time by many influences. The goal of this study is to explore and separate these potential influences including changes in the water level of the Uzboi Vallis, its erosion base. The other aim is to detect and describe the effects of tectonic processes for we have found potential evidence. Our working hypothesis is that Nirgal Vallis was once a river valley: our study analyses this possibility. The climate of Mars has undergone drastic changes in the past, and liquid water is currently not stable on the surface. The formation of former river valleys after the active wet period continued, including Nirgal Vallis. Morphometric techniques were applied based on MOLA, THEMIS, and HiRISE data. The topography of the Nirgal Vallis have been analyzed by swath analysis, calculation of various geomorphometric parameters, and runoff model. HiRISE digital terrain models having decimeter-scale resolution derived from the HiRISE stereopairs have been used for the detailed analysis.</div><div>A subdivision of the Nirgal Vallis according to its tectonic geomorphological structures was established. The swath analysis and the runoff model calculation show that, although the valley does not have a strict thalweg today, i.e., water currently cannot flow down it, the valley does have a trend of slope along the whole length and even intermittent slope changes can be observed along the whole valley. Several small-scale morphological features were also identified using MOLA data.</div><div>We conclude that the tectonic processes have transformed the morphology of the riverbed: it is divided into small sections (closed basins) so that currently water would not be able to flow down in it. Extraterrestrial (i.e. effects from outside Mars) causes on Mars also influence this, i.e. the formation of larger and smaller craters has also left its mark on the topography. We interpret the subperpendicular elongated morphological features on the plateau surrounding Nirgal Vallis as wrinkle ridges: their size, shape and spacing is similar to those identified by previous authors elsewhere. We also found evidence that the valley bottom has also been modified by the processes that formed the wrinkle ridges. Our observations imply younger tectonic influence of the area, presumably, postdating the fluvial erosional regime.</div><div>The Luki Crater, located near the confluence of Nirgal Vallis and Uzboi Vallis, has also been analyzed, and evidence has been found to be tectonically modified. This modification is in congruence with the results of other analyses indicating tectonic influence of Nirgal Vallis. Our results may also have implications for formation of the Uzboi Vallis, though this will require further studies.</div><div>These results suggest that the a","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"262 ","pages":"Article 106128"},"PeriodicalIF":1.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878449","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}
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