Planetary and Space Science最新文献

{"title":"The chemistry and mineralogy of the LX high-fidelity lunar regolith simulants","authors":"Joel Patzwald ,&nbsp;Ferry Schiperski ,&nbsp;Hannah Fisher ,&nbsp;Thomas Neumann ,&nbsp;Enrico Stoll","doi":"10.1016/j.pss.2025.106190","DOIUrl":"10.1016/j.pss.2025.106190","url":null,"abstract":"<div><div>To support sustainable solar system exploration, humans must harness resources from celestial bodies like the Moon to build infrastructure and obtain essential consumables, including water and oxygen. Lunar regolith, a loose rock layer covering the Moon’s surface, is a key resource for in-situ resource utilisation (ISRU) technologies. Developing and testing these technologies on Earth relies on the use of accurate simulant materials. In prior studies, the LX lunar regolith simulant system was developed and the base simulants LX-T100 (anorthosite) and LX-M100 (basalt) were thoroughly characterised in terms of their bulk mineralogical and bulk chemical composition, particle size distribution, particle morphology, density, void ratio and porosity, adsorption and BET-specific surface area, compressibility, flow, magnetic and optical properties. This work focuses on the LX high-fidelity simulants, specifically their mineralogy and chemistry. The high-fidelity simulants are composed of four source rocks, namely the anorthosite of LX-T100, the basalt of LX-M100, as well as a harzburgite as a source for olivine and pyroxene and an ilmenite ore as a source for ilmenite. The bulk mineralogy and chemistry of the harzburgite and ilmenite ore, as well as the crystal chemistry of all four source rocks, were analysed and the results were compared with the lunar samples from the Apollo and Luna missions. Finally, a deviation analysis was carried out in which the bulk chemistry of the LX high-fidelity simulants and 13 other relevant simulants from research and industry were compared with the chemical composition of the lunar soil at the landing sites of the Apollo, Luna and Chang’e 5 missions. It was shown that of all simulants, the LX high-fidelity simulants can on average best mimic the chemical composition of the lunar soil. The findings from these investigations deepen the understanding of the LX lunar regolith simulants, increasing their reliability for scientific research.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106190"},"PeriodicalIF":1.7,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220428","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":"Coupled mineralogical and nano-mechanical characterization of calcium sulfate veins in Martian analog rocks: Implications for Mars sample return drilling strategies","authors":"A. Ettehadi ,&nbsp;M. Radonjic ,&nbsp;M. Mokhtari ,&nbsp;R.C. Anderson","doi":"10.1016/j.pss.2025.106203","DOIUrl":"10.1016/j.pss.2025.106203","url":null,"abstract":"<div><div>Mars sample collection is often hindered by the mechanical fragility of calcium sulfate-filled fractures, which are prone to fragmentation under drilling-induced stress. This study presents a coupled mineralogical and nano-mechanical investigation of such fracture systems in terrestrial Martian analog rocks, aiming to inform Mars Sample Return (MSR) drilling strategies. X-ray diffraction (XRD), scanning electron microscopy in backscattered mode (SEM-BSE), and energy-dispersive spectroscopy (EDS) reveal that gypsum is the dominant fracture-filling phase, exhibiting spatial continuity but considerable heterogeneity at vein–matrix interfaces. The host matrix consists primarily of quartz, albite, and dolomite, creating stark mineralogical contrasts that control fracture evolution and mechanical response. Nano-indentation testing was conducted across gypsum, matrix, and interfacial regions, revealing significant differences in mechanical properties. Gypsum zones show pronounced plasticity and low elastic modulus (E ≈ 10–20 GPa), while matrix minerals such as quartz exhibit higher stiffness (E &gt; 100 GPa) and hardness. Critically, vein–matrix interfaces display intermediate properties and increased indentation depths, indicating weak interfacial bonding and stress localization. These mechanically vulnerable zones are likely to fracture or delaminate during coring operations. By integrating mineralogical heterogeneity with mechanical behavior, this study identifies key failure mechanisms in sulfate-rich terrains and formulates drilling and coring recommendations tailored to mitigate damage. The findings provide essential guidance for tool design, load control strategies, and sample targeting, ultimately improving the reliability of core recovery and scientific return in future Mars exploration missions.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106203"},"PeriodicalIF":1.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220429","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":"Secondary electron generation by sub-keV ion and energetic neutral particle impacts on a surface","authors":"S. Gopalakrishnan,&nbsp;X. Wang,&nbsp;H.-W. Hsu,&nbsp;M. Horányi","doi":"10.1016/j.pss.2025.106202","DOIUrl":"10.1016/j.pss.2025.106202","url":null,"abstract":"<div><div>The secondary electron yield (SEY) from sub-keV ion and neutral particle impacts on a stainless steel surface has been investigated in the laboratory. Sub-keV ions were generated using a large Kauffman ion source and energetic neutral particles (ENPs) were generated from ion-neutral charge-exchange collisions. It is found that the SEY from ion impacts increases with the ion kinetic energy, reaching the yield of <span><math><mo>∼</mo></math></span>0.25-0.4 by the 1000 eV ion impact, depending on the surface cleanliness. The SEY from neutral impacts is about an order of magnitude lower than from ion impacts, indicating that the electrostatic potential energy plays a bigger role in generating secondary electrons than the kinetic energy in this energy range. It is shown that the SEY is higher for impacts by lighter ion species. The effect of surface cleanliness is investigated, showing an increase in the SEY for a contaminated surface. Our results show that secondary electrons generated from sub-keV ion impacts are non-negligible and may play a more pronounced role in determining the surface charge in various space environments, such as permanently shadowed regions (PSRs) on airless bodies. The SEY measured from sub-keV ENP impacts is useful for determining the surface charge of a spacecraft moving through dense planetary atmospheres.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106202"},"PeriodicalIF":1.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158459","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":"Mercury's early thermal evolution and core formation in the presence of impact-generated atmosphere during accretion","authors":"Gurpreet Kaur Bhatia,&nbsp;Sumit Sankhyan","doi":"10.1016/j.pss.2025.106201","DOIUrl":"10.1016/j.pss.2025.106201","url":null,"abstract":"<div><div>Understanding a planet's early thermal evolution and differentiation is crucial to comprehending the distribution of volatiles in its different reservoirs. Mercury is now known as a volatile rich planet. It has carbon saturated core, deeply buried volatile rich layers, a diamond layer at the core-mantle boundary and graphite floating at the crust. For carbon saturation, Mercury is believed to have accreted from Enstatite/CB chondrite rich building blocks. In the present work, we studied the early thermal evolution and core formation in the interior of Mercury by considering its accretion from water rich Enstatite chondrites prior to the dispersal of solar nebula. The heat sources for the melting and differentiation of Mercury include the decay energy of SLR ²⁶Al and the blanketing effect of the impact generated H₂O+CO+H₂ along with primordial atmosphere. The results suggest the complete core formation with lowest assumed water content in the building blocks Mercury for accretion timescales ≤1.5 Myr after the formation of CAIs. The longer accretion timescales, it needed higher abundance of water to cause significant blanketing effect at the surface. During differentiation process, the volatiles dissolved in the magma ocean under the pressure of overlying atmosphere, could partition into the core. Hence, the outcomes of present study have implications to explain the distribution of volatile in the interior of Mercury. Conversely, under the strong blanketing effect, the surface silicate could vaporize and dissolve in the steam atmosphere.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106201"},"PeriodicalIF":1.7,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220426","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 small bodies perturbed by an eccentric giant planet","authors":"Tabaré Gallardo,&nbsp;Rodrigo Cabral","doi":"10.1016/j.pss.2025.106198","DOIUrl":"10.1016/j.pss.2025.106198","url":null,"abstract":"<div><div>The dynamics of small bodies perturbed by an eccentric planet was done mostly under the assumption of well separated orbits using analytical approximations appropriate for the hierarchical case. In this work we study the dynamics of small bodies in a wide range of eccentricities and inclinations perturbed by a giant planet with <span><math><mrow><msub><mrow><mi>e</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>4</mn></mrow></math></span>, in the non-hierarchical case. We consider small bodies both interior and exterior to the planet. We apply semi-analytical models for the study of resonances and the properties of the secular disturbing function. We perform a frequency analysis of numerical integration of the exact equations of motion to obtain the proper frequencies and corresponding dynamical secular paths. We study the dependence of proper frequencies with the initial mutual inclination and we find a critical inclination around 30 degrees for which the pericenter proper frequency vanishes giving rise to the increase of small bodies eccentricities followed by unstable dynamics. This happens for both interior and exterior small bodies and constitutes a stability barrier in the inclination. For greater inclinations the ZLK mechanism dominates both populations. By means of numerical integration of thousands of small bodies we reproduce the well known pericenter shepherding, but for the exterior populations with low inclinations we also find concentrations of the longitude of the ascending node in the direction of the planetary line of apsides.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106198"},"PeriodicalIF":1.7,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060814","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":"MICROorganisms under simulated ICY moon environments: supporting solar system exploration (MICRO ICY project)","authors":"C. Pacelli ,&nbsp;A. Cassaro ,&nbsp;L. Cocola ,&nbsp;A. Cordone ,&nbsp;M. Del Bianco ,&nbsp;M. Esposito ,&nbsp;F. Ferranti ,&nbsp;M. Ferrara ,&nbsp;D. Giovannelli ,&nbsp;L. Manfrin ,&nbsp;L. Parca ,&nbsp;L. Poletto ,&nbsp;L. Tonietti ,&nbsp;A. Zinzi","doi":"10.1016/j.pss.2025.106200","DOIUrl":"10.1016/j.pss.2025.106200","url":null,"abstract":"<div><div>The exploration of icy moons in the solar system marks a new chapter in the search for extraterrestrial life, with next-generation missions targeting these promising environments. Cassini's flybys of Enceladus revealed a global subsurface ocean containing organic compounds and biologically available nitrogen, suggesting potential conditions for life as we know it. Other moons with subsurface oceans, such as Europa, Titan, Ganymede, and Callisto, are now considered more common in the cosmos than once believed. Enceladus thus provides a critical platform for advancing astrobiological research and technology.</div><div>Given the challenges of space exploration, Earth-based (both in-situ and laboratory) experiments are crucial for interpreting remote data and understanding icy moon processes. Terrestrial hydrothermal sites, similar to those expected on Enceladus, shed light on the origins and preservation of life, expanding our knowledge of the habitability concept. Microbial extremophiles thriving in these environments allow to refine life's boundaries and support the search for life elsewhere.</div><div>In this context, the MICROICY project aims to: (i) study microbial communities in the Strýtan alkaline shallow-water hydrothermal vents in Iceland, analogues to Enceladus' hydrothermal vents; (ii) assess the adaptation mechanisms of extremophiles under Enceladus-like conditions; and (iii) detect gas biosignatures of microbial activity using a mass spectrometry detector. These findings will support the use of gas biosignatures in next-generation astrobiology missions, advancing the exploration of Enceladus and other icy moons.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106200"},"PeriodicalIF":1.7,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106174","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":"Nonlinear theory of dust-acoustic waves in planetary plasmas with non-ideal dust fraction","authors":"Alexander E. Dubinov,&nbsp;Ilya N. Kitayev","doi":"10.1016/j.pss.2025.106199","DOIUrl":"10.1016/j.pss.2025.106199","url":null,"abstract":"<div><div>A non-ideal dusty planetary plasma was considered, consisting of a mixture of three gases – gases of inertialess electrons and ions, and a gas of negatively charged dust particles. Electrons and ions in the plasma were thought to be Boltzmann-distributed, and the dust gas obeyed the equation of state of the non-ideal gas previously deduced by Avinash. Stationary dust-acoustic waves DAWs in such plasma were studied for the first time. The study was carried out in the gas dynamic approach.</div><div>The linear theory of DAWs has been developed, within the framework of which a dispersion equation was derived and an exact expression for the linear velocity of a dust sound was obtained.</div><div>The non-linear theory of large amplitude DAWs in a non-ideal dust plasma based on the Bernoulli pseudopotential method was first developed. Pseudopotential analysis showed that stationary DAWs in the considered plasma can have the form of either a nonlinear periodic wave or the form of solitons. The wave velocity ranges in these two forms are defined.</div><div>The dependence of the maximum velocity of DA-solitons and the maximum Mach number on the value of the parameter of non-ideality is calculated. It was also found that with an increase of the parameter of non-ideality, the amplitude of the extreme soliton decreases, and its width at half-maximum practically does not depend on this parameter.</div><div>The developed theory can be used to describe DAWs appearing in dense non-ideal plasmas near planets, their satellites and comets.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106199"},"PeriodicalIF":1.7,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057159","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":"Properties of novel LX lunar regolith simulant system — the base simulants: Part 2","authors":"Joel Patzwald ,&nbsp;Rafael Kleba-Ehrhardt ,&nbsp;Tjorben Griemsmann ,&nbsp;Norbert Nowaczyk ,&nbsp;Stefan Linke ,&nbsp;Ludger Overmeyer ,&nbsp;Enrico Stoll ,&nbsp;David Karl","doi":"10.1016/j.pss.2025.106189","DOIUrl":"10.1016/j.pss.2025.106189","url":null,"abstract":"<div><div>Sustainable and fast exploration and colonisation of our solar system are only possible if humans learn to use the resources of other celestial bodies, such as our Moon, to build settlements and infrastructure, extract valuable materials for the production of secondary goods and obtain consumables such as water and oxygen for life support and as fuel. The most abundant resource on the Moon is the lunar regolith, a layer of loose pulverised rock material covering the Moons surface many meters thick. So-called ISRU (in-situ resource utilisation) technologies are being developed to make use of this material. To develop and test such technologies on Earth, analogue materials (simulants) are essential. In a previous study, the LX lunar regolith simulant system was developed for this purpose, and the base simulants LX-T100 and LX-M100 were characterised regarding their mineralogy and chemistry, particle size distribution, particle morphology, density, void ratio and porosity. This study presents the second part of a comprehensive characterisation of the base simulants, aimed at providing detailed insights into their adsorption behaviour and specific surface area, compressibility, flow properties, magnetic properties and optical properties. Using the Brunauer–Emmett–Teller (BET) method, the specific surface area was precisely quantified, being, for example, relevant to the adhesion and reactivity of lunar dust. Compressibility was measured using an oedometer test, providing insight into the settlement behaviour of the simulants under load. Flow properties were assessed through a series of dynamic and static tests, including angle of repose, Hausner ratio, rheometry and direct shear measurements, to determine the simulant’s handling and transportation behaviour. The magnetic properties were characterised to understand the magnetic susceptibility and remanence, which are crucial for dust mitigation strategies and electromagnetic interference assessments. Spectral reflectance was evaluated using spectrophotometry across relevant wavelengths, providing useful data for remote sensing calibration and surface composition analysis. It was shown that the simulants are good analogues for simulating adsorption, compression, and flow behaviour. However, their ability to represent magnetic and optical properties remains limited. The results from these investigations contribute to a more thorough understanding of the LX base simulants, enhancing their fidelity for scientific research.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106189"},"PeriodicalIF":1.7,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020372","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":"Directional Analysis of Fractures at ESA’s Rosalind Franklin landing site, Oxia Planum, Mars","authors":"Andrea Apuzzo ,&nbsp;Alessandro Frigeri ,&nbsp;Francesco Salvini ,&nbsp;Jeremy Brossier ,&nbsp;Maria Cristina De Sanctis ,&nbsp;Francesca Altieri ,&nbsp;Gene Walter Schmidt ,&nbsp;Ma_MISS team","doi":"10.1016/j.pss.2025.106169","DOIUrl":"10.1016/j.pss.2025.106169","url":null,"abstract":"<div><div>The Rosalind Franklin rover of the European Space Agency’s ExoMars program is going to land at Oxia Planum, Mars after its launch scheduled in 2030. The mission aims to look for evidence of past and present life on Mars. The presence of fractured rocks at the landing site is of interest to the astrobiological goal of the mission because fractures represent conduits that could facility circulation of fluids. Our study is devoted to observing the orientations of the fractures and to investigate their possible origin by single or multiple processes. We first selected 50 regions of interest (ROIs) in areas of pronounced fracturing, using images from the High-Resolution Imaging Science Experiment (HiRISE) as a basemap. We then analysed the orientation of the fractures and how it varied with length. Statistical analysis shows that fractures predominantly have an E-W orientation, especially in longer fractures, while shorter fractures have a more random pattern. These orientation trends suggest a geological history influenced primarily by both hydrofracturing and tectonic processes. The preferred orientation, which is consistent with north-south tectonic shortening structures documented in the vicinity of the region, is likely to reflect a regional tectonic event between 3.7 and 4.0 billion years ago. The origin of the fractures may have promoted the migration of subsurface fluids through the fractured bedrock, potentially creating habitable conditions for microbial life. Our first study on fractures supports other studies on the geology of the ancient terrains at Oxia Planum, which hides a complex geologic history needing to be unravelled from different perspectives.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"267 ","pages":"Article 106169"},"PeriodicalIF":1.7,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907006","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":"Recent Chemo-morphological coma evolution of comet 67P/Churyumov–Gerasimenko","authors":"Brian P. Murphy ,&nbsp;Cyrielle Opitom ,&nbsp;Colin Snodgrass ,&nbsp;Sophie E. Deam ,&nbsp;Léa Ferellec ,&nbsp;Matthew Knight ,&nbsp;Vincent Okoth ,&nbsp;Bin Yang","doi":"10.1016/j.pss.2025.106178","DOIUrl":"10.1016/j.pss.2025.106178","url":null,"abstract":"<div><div>We present VLT/MUSE observations of comet 67P/Churyumov-Gerasimenko during its 2021 perihelion passage, from which we generated simultaneous maps of dust, [OI], C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, NH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and CN comae across 12 pre- and post-perihelion epochs. These maps reveal the evolutionary and compositional trends of 67P’s coma and further enrich the context and findings of ESA’s Rosetta mission. Dust and gas species displayed distinct structures, where NH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and CN signals were uniquely associated with known dust fans, raising the question of possible correlation to the dust and contributions of extended sources. Localised fitted NH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> scale lengths were 1.5-1.9<span><math><mo>×</mo></math></span> larger than those fitted for the rest of the coma, which is consistent with an extended source component for northern pre-perihelion emissions. In the southern hemisphere, CN was correlated with a prominent and sharp dust structure, potentially revealing an extended source origin via larger dust particles that preserve the CN parent species, as evidenced by higher spectral slopes in the region. Gas maps depicted two distinct evolutionary regimes: (1) evolving H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O ([OI]¹D) and C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> emissions driven by nucleus sublimation and subsolar insolation, and (2) stable NH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and CN emissions associated with seasonal dynamics and possible distributed sources. Dust spectral slope maps revealed spectral slope trends consistent with Rosetta findings, while green/red [OI] ratios generally indicate a coma dominated by H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O.</div></div>","PeriodicalId":20054,"journal":{"name":"Planetary and Space Science","volume":"268 ","pages":"Article 106178"},"PeriodicalIF":1.7,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989518","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}