Icarus最新文献

{"title":"Assessing the depth of the regolith around radar-dark halo craters on the Moon","authors":"A.D. Thaker ,&nbsp;C.D. Neish","doi":"10.1016/j.icarus.2025.116623","DOIUrl":"10.1016/j.icarus.2025.116623","url":null,"abstract":"<div><div>Impact cratering is a ubiquitous geological process in our Solar System and plays an important role in shaping the landscape of many planetary bodies, including the Moon. Our study focuses on the unique radar-dark halo craters (RDHCs) on the Moon, which are surrounded by distinctive, ring-shaped structures (i.e., haloes) that have unusually low radar backscatter. Our aim is to understand the interaction between the ejecta emplacement around RDHCs and the lunar regolith by assessing the local depths of the regolith surrounding RDHCs. We use the morphology of small impact craters (∼10–250 m) to infer the depth of the regolith around these RDHCs. We examine small craters in images from the Lunar Reconnaissance Orbiter's (LRO) Narrow Angle Camera (NAC) within the continuous and discontinuous ejecta blankets of five RDHCs. We then compare these results with those of five non-RDHCs. Overall, we observe similar regolith characteristics around RDHCs and non-RDHCs. Interestingly, our results do not show a strong correlation between crater age and regolith depths. This suggests that despite continued bombardment, the regolith layer is not getting significantly deeper with age. In addition to impact gardening, there may be other factors contributing to regolith formation around impact craters on the Moon. Additionally, our study suggests that the flat-floor small crater morphology is more dominant for the RDHCs than non-RDHCs, which points to a deeper and more uniform mixture of regolith in these regions. Our study thus suggests that the emplacement of fine-grained RDH material over bedrock disrupts the ordinary regolith formation. We conclude that a careful re-examination of our understanding of regolith formation and evolution is necessary.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116623"},"PeriodicalIF":2.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis of the olivine cumulate outcrop Issole – The missing link between the Séítah and Máaz formations in Jezero crater, Mars","authors":"Juan David Hernández-Montenegro ,&nbsp;Tanya V. Kizovski ,&nbsp;Allan H. Treiman ,&nbsp;An Y. Li ,&nbsp;Paul D. Asimow ,&nbsp;Mariek E. Schmidt ,&nbsp;Yang Liu ,&nbsp;Josh Labrie ,&nbsp;Abigail L. Knight ,&nbsp;Michael M. Tice ,&nbsp;David A. Klevang ,&nbsp;Scott VanBommel ,&nbsp;Lawrence A. Wade ,&nbsp;Joel A. Hurowitz ,&nbsp;Adrian J. Brown ,&nbsp;Morgan L. Cable ,&nbsp;Abigail C. Allwood ,&nbsp;the PIXL team","doi":"10.1016/j.icarus.2025.116620","DOIUrl":"10.1016/j.icarus.2025.116620","url":null,"abstract":"<div><div>Two lithologic units have been mapped and studied on the floor of Jezero crater, Mars: Séítah, which consists of layered olivine-rich cumulates, and Máaz, a series of basaltic to trachyandesitic lava flows. While Séítah and Máaz are close in proximity and stratigraphy, their potential geologic and petrological relationship remains unclear. Here, we present observations from the Planetary Instrument for X-ray Lithochemistry (PIXL) of an olivine cumulate outcrop – <em>Issole</em> – within the Séítah formation. The rock analyzed at <em>Issole</em> is a wehrlite dominated by olivine (Fo_46±1) and interstitial phases, including augite, late olivine, spinel, and feldspathic material. Compared to other outcrops from Séítah, <em>Issole</em> is more iron-rich and records substantial alteration processes. We combine mineral chemistry, textural analysis, and thermodynamic modeling to show that Séítah olivines crystallized from a basaltic parent magma, compositionally similar to the most primitive basalts in the Máaz formation. Crystallization of this parent magma produces residual melts that follow the magmatic differentiation trend defined by Máaz basalts. Moreover, the mineral assemblages predicted by our model during crystallization are consistent with observations from Séítah rocks but show some differences in composition. These differences can be reconciled by considering post-cumulus processes that modified the mineral assemblage in Séítah, including Fe<img>Mg exchange between olivine and pyroxene. Our results indicate that Séítah and Máaz are likely genetically related, and their formation involved both accumulation of crystals at depth and eruption of lavas. The emplacement of Séítah likely occurred as a near-surface, sill-like igneous intrusion into previously erupted Máaz lava flows. The relationship between Séítah and Máaz demonstrates that magmatic differentiation processes, similar to those responsible for the formation of some Martian meteorites, can produce highly diverse lithologies and mineral textures in the Martian crust.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116620"},"PeriodicalIF":2.5,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How does topography affect wind abrasion on Mars? Recently observed shifts in ventifact orientation at Gale crater","authors":"Daniel Y. Zhou ,&nbsp;Madison L. Turner ,&nbsp;William Rapin ,&nbsp;Juergen Schieber ,&nbsp;Amelie L. Roberts ,&nbsp;Aster C. Cowart ,&nbsp;Megan E. Hoffman ,&nbsp;Bernard Hallet ,&nbsp;Steve G. Banham ,&nbsp;Deirdra Fey ,&nbsp;Kevin W. Lewis ,&nbsp;Sanjeev Gupta ,&nbsp;Claire E. Newman ,&nbsp;Ashwin R. Vasavada ,&nbsp;Cathy M. Weitz ,&nbsp;William E. Dietrich ,&nbsp;John A. Grant ,&nbsp;Daniel Viúdez-Moreiras ,&nbsp;Edwin S. Kite","doi":"10.1016/j.icarus.2025.116605","DOIUrl":"10.1016/j.icarus.2025.116605","url":null,"abstract":"<div><div>Wind abrasion is the dominant erosive process inferred from observations by <em>Curiosity</em> during its traverse in Gale crater, but how and how fast wind scours Mount Sharp is unclear. Here, we infer formative wind direction from ventifacts (wind-eroded rock fragments) measured from <em>Curiosity</em>'s recent traverse. We compare these measurements to previous ones and to wind model predictions, and attempt to estimate the current rate of wind erosion near <em>Curiosity</em>'s location on Mount Sharp. Ventifacts in this study indicate winds blowing south-southeast, agreeing with previous studies on the floor of Gale crater, but differing from studies at the base of the mountain slope. Upslope abrasive wind flows predominate, consistent with idealized models. At some sites, ventifacts are oriented both upslope and downslope on Mount Sharp, suggesting bimodal wind direction at the mountain, agreeing with circulation models that predict diurnal reversals. Using crater-retention age statistics at one site, we estimate a ∼ 3.5 ± 0.8 μm/Earth year (yr) upslope horizontal erosion rate at Mount Sharp. We suggest the observed ventifacts formed when Mars' obliquity and climate regime were similar to those in the present day.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116605"},"PeriodicalIF":2.5,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of meteor shower observed by two collocated meteor radars at low latitudes","authors":"Maolin Lu ,&nbsp;Wen Yi ,&nbsp;Xianghui Xue ,&nbsp;Iain Reid ,&nbsp;Tingdi Chen ,&nbsp;Jinsong Chen ,&nbsp;Na Li","doi":"10.1016/j.icarus.2025.116610","DOIUrl":"10.1016/j.icarus.2025.116610","url":null,"abstract":"<div><div>We present results in which we compare simultaneous meteor shower observations using two meteor radars located in Kunming, China (25.6°N, 103.8°E). These are the 37.5 MHz ‘all-sky’ Kunming meteor radar (KMMR) and the 53.1 MHz Kunming Stratospheric–Tropospheric ST/Meteor radar (KMST). We first explore the Southern Delta Aquariids (SDA) meteor shower, one of the most active annual sources in the southern hemisphere, as an example, and one with ambiguous radiant. From this, we propose a new approach to determine the azimuthal angular deviation from true north for the radars and find a result of 14.7° on the KMMR and less than 1° for the KMST. These results are used to correct the receiving antenna baseline of the meteor radars. After correcting for this in the Horizontal Coordinate System of the KMMR, we find more than 2000 shower meteors originating from the radiant of Right Ascension (R.A.) =339.8° ± 2.7°, and declination (Dec.) = −16.9° ± 1.7° (J2000), and more than 1300 shower meteors from a region of R.A. = 339° ± 2.9°, Dec. = −16° ± 1.8° (J2000) from the KMST. A consistent finding between the radars was that SDA outbursts occur between UTC 1400 and 0100 with a geocentric velocity of ∼39 km/s. We then expended the period of investigation to 14 months to obtain a survey of meteor showers including the Geminids and Quadrantids. In this larger survey, 9 meteor showers were simultaneously detected by the two meteor radars, with good consistency on radiants and velocity. This demonstrates that it is possible to evaluate the angular deviation of any meteor radar in any specific period by using this new approach. We also found two previously unidentified meteor showers.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116610"},"PeriodicalIF":2.5,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining the role of water in Martian lowland gully formation","authors":"Rowan I. Huang ,&nbsp;Virginia C. Gulick","doi":"10.1016/j.icarus.2025.116612","DOIUrl":"10.1016/j.icarus.2025.116612","url":null,"abstract":"<div><div>A variety of processes have been proposed to form Martian gullies with little consensus reached. Detailed mapping combined with morphological and morphometric studies for gully and channel systems on Earth can distinguish these processes from one another, as well as measure the degree to which gullies are formed by liquid water. These parameters include tributary stream orders and magnitudes; drainage densities; channel profile concavities; gully cross-sectional profiles; sinuosity; gully, apex, and apron slopes; and gully/apron volumes.</div><div>We applied these morphometrics, detailed gully mapping, and morphologic studies to four gullied craters in the Northern Lowlands of Mars. Morphometric parameters indicate that their morphology is most consistent with a fluvial origin, especially in craters at 63 N, 53 N and 48 N latitude. The gullies in these craters have many first-order tributaries contributing to high tributary stream orders up to 4 and magnitudes ranging from 10 to 65, drainage densities ranging from 8 to 60 km/km², and concave channel profiles with concavity indices between 0.102 and 0.185. These gullies also form on shallow slopes between 8 and 20 degrees, below the angle of kinetic friction (21 degrees), which indicates fluid emplacement of materials. Gullies in a crater located at 60 N latitude and on the west wall of the 53 N Crater are more poorly developed, with lower tributary integration reflected in the stream magnitude and stream order values (ranging from 2 to 3 and 28 respectively), straight channels, and lower concavity values &lt;0.1 indicating a smaller contribution of water to their formation. Morphological characteristics within the gully systems analyzed in this study, such as multiple apron formation, cross-cutting features, and subsequent deposition indicate that gully formation was episodic. Reduced channel sinuosity and smaller deposits imply that gully activity experienced less water availability over time as conditions within the craters became less suitable for liquid water. A source of water that is compatible with the observed morphologies would be basal melt from dusty snowpacks. These snowpacks might have been deposited at higher obliquity or formed from the cold-trapping of steam freed from the subsurface by impact and the resulting post-impact hydrothermal system.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116612"},"PeriodicalIF":2.5,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring the degree of clustering and diffusion of trans-Neptunian objects","authors":"Gabriele Pichierri,&nbsp;Konstantin Batygin","doi":"10.1016/j.icarus.2025.116560","DOIUrl":"10.1016/j.icarus.2025.116560","url":null,"abstract":"<div><div>The outer solar system is populated by a broad aggregate of minor bodies, which occupy orbits whose dynamical character ranges from long-term stable to rapidly diffusive. We investigate the chaotic properties of known distant trans-Neptunian objects (TNOs) by numerically integrating TNO clones and statistically analyzing their orbital diffusion. Comparing the measured diffusion with an analytical criterion yields a dynamically motivated separation into classes of stable, metastable and unstable objects. We then measure the level of clustering of the longitudes of perihelia and of the orbital poles, as functions of orbital distance and of their stability properties. Distant (meta)stable objects appear increasingly clustered in perihelion around <span><math><mrow><mi>ϖ</mi><mo>∼</mo><mn>5</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> for increasing semi-major axis, while the orbits of unstable objects are well described by two, roughly equally-populated groups of “clustered” and “anti-clustered” objects, with means around <span><math><mrow><mo>∼</mo><mn>2</mn><msup><mrow><mn>5</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> and <span><math><mrow><mo>∼</mo><mn>20</mn><msup><mrow><mn>5</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span> respectively. We further find that, compared to the solar system’s total angular momentum vector, the mean orbital poles of distant TNOs are significantly more misaligned for (meta)stable objects, while they remain roughly aligned for unstable objects. TNOs with intermediate orbital periods also appear to be misaligned with respect to the forced plane predicted by secular theory with the known planets. This gradation based on stability, if validated further by the upcoming VRO survey, necessitates a dynamical explanation.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116560"},"PeriodicalIF":2.5,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sun Close-Encounter model of long-period comet and Meteoroid Orbit Stochastic Evolution","authors":"Stuart Pilorz ,&nbsp;Peter Jenniskens","doi":"10.1016/j.icarus.2025.116559","DOIUrl":"10.1016/j.icarus.2025.116559","url":null,"abstract":"<div><div>The dynamical evolution of long-period comets (LPCs) and their meteoroid streams is usually described with the Sun as the primary body, but over most of their orbits the Solar System barycenter (SSB) is effectively the orbital focus. Detailed numerical integrations show that the orbital elements in the barycentric reference frame are nearly constant, except within the orbit of Jupiter where the comet or meteoroid shifts to a heliocentric orbit. Here we show that this encounter can be modeled in the barycentric frame analogously to how planetary close encounters are treated in the heliocentric frame, with the comet captured into an elliptic orbit about the Sun as it in turn orbits SSB. Modeling the encounters as a two-body interaction in the SSB frame gives a different insight into the dynamics than offered by secular perturbation analyses, and reveals that a large portion of the stochasticity seen in the evolution of the comet’s orbit is due to the Sun’s state relative to SSB at the time of encounter. LPCs sample the Sun’s state randomly at each return, so that a statistical characterization of Sun’s state is sufficient to determine the qualitative evolution of their orbits, including stream dispersion. The barycentric orbital elements are shown to execute random walks well-characterized by Maxwellian distributions. This is superimposed atop a systematic orbital precession induced by planetary torques. Planetary close encounters add a second stochastic component, but this component does not typically dominate the solar perturbations. Based on the statistics of Sun’s state alone, the age of a long-period comet meteoroid stream in a given orbit can be derived to reasonable precision from the observed random dispersion of the angular orbital elements at Earth.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116559"},"PeriodicalIF":2.5,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Layered remnant deposits in Hellas Planitia, Mars as the remains of ancient ice mounds","authors":"Eva Z. Petrini ,&nbsp;Michael M. Sori","doi":"10.1016/j.icarus.2025.116604","DOIUrl":"10.1016/j.icarus.2025.116604","url":null,"abstract":"<div><div>Hellas Planitia is the site of many icy features in craters whose formation mechanisms offer insights into the climate processes of Mars. Layered remnant deposits (LRD) appear as crater deposits with distinct layers and have an unclear formation because of their frequent existence in the southern half of craters. We create an inventory of LRDs within Hellas Planitia using Thermal Emission Imaging System (THEMIS), Context Camera (CTX), and HiRISE images when available to measure key characteristics of LRDs and their host crater. We find 245 LRDs. Based on trends in our inventory, we propose LRDs result from old, crater-filling ice mounds that had preferential sublimation on the northern side leaving the present-day remnant in the southern portion of the crater. Understanding the formation of LRDs provides valuable insights into the broader narrative of Mars' climatic history, offering clues about past environmental conditions in the planet's Amazonian era.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"436 ","pages":"Article 116604"},"PeriodicalIF":2.5,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Pyroxenite mantle on Mercury? Experimental insights from enstatite chondrite melting at pressures up to 5 GPa","authors":"Asmaa Boujibar ,&nbsp;Kevin Righter ,&nbsp;Emmanuel Fontaine ,&nbsp;Max Collinet ,&nbsp;Sarah Lambart ,&nbsp;Larry R. Nittler ,&nbsp;Kellye M. Pando","doi":"10.1016/j.icarus.2025.116602","DOIUrl":"10.1016/j.icarus.2025.116602","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Enstatite chondrites are potential source material for the accretion of Mercury due to their reduced nature and enrichment in volatile elements. Understanding their melting properties is therefore important to better assess a scenario where Mercury formed from these chondrites. Here, we present experimental data on the partial melting of a modified EH4 Indarch enstatite chondrite, which was adjusted to have 18 % more metallic Si than SiO&lt;sub&gt;2&lt;/sub&gt; in mass, yielding an oxygen fugacity of 3.7 ± 0.6 below iron-wüstite redox buffer and 12 wt% Si in the metal. Experiments were performed from 0.5 to 5 GPa using piston cylinder and multi-anvil apparatuses. Results indicate that the stability field of enstatite expands relative to olivine. This expansion is likely due to the presence of Ca-S and Mg-S complexes in the silicate melt, which enhance SiO&lt;sub&gt;2&lt;/sub&gt; activity and promote enstatite crystallization. Silicate melts present a correlation between Ca and S concentrations, like the global patterns seen on Mercury's surface but with higher sulfur abundances. Additionally, sulfides show enrichment in Mg and Ca, up to 22 and 13 wt% respectively, the main remaining cations being Fe, Cr and Mn. These high Mg and Ca contents are observed at low temperatures and high silica content in the silicate melt, respectively. Partial melting of this reduced EH4 chondrite yields a large range of silicate melt compositions, due to the Mg- and Ca-rich sulfides which act as significant residual phases. High-pressure melts (2 to 5 GPa, 160–400 km depth in Mercury) are Mg-rich, similar to those in Mercury's high‑magnesium region (HMR), while low-pressure melts (0.5 to 1 GPa, 40–80 km depth) are Si-rich, comparable to the northern volcanic plains (NVP). Results suggest that a large fraction of Mercury's surface aligns compositionally with these melts, implying that Mercury's mantle could predominantly have a pyroxenitic composition. However, regions with differing compositions, such as aluminum-rich areas, like the Caloris basin, suggest local variability in mantle geochemistry. The HMR chemistry indicates melting at pressures up to the base of Mercury's mantle, possibly due to a large impact. Our study also explores whether the surface compositions could result from mixing processes like impact gardening or polybaric melting and magma mixing. The findings suggest that areas such as the intercrater plains and heavily cratered regions could be mixtures of melts from different pressures, ranging from 0.5 to 5 GPa, which corresponds to the crust-mantle to core-mantle boundaries. Overall, our results show that if Mercury formed from materials similar to enstatite chondrites, batch melting of its primitive pyroxenite mantle would yield magmas with compositions resembling those of most rocks observed on the surface. While the exact olivine content of the mantle remains uncertain, the residual mantle is likely enstatite-rich due to the extensive stability of enstatite","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"437 ","pages":"Article 116602"},"PeriodicalIF":2.5,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A highly resonant Neptunian region: A systematic search for two-body and three-body mean-motion resonances","authors":"Evgeny Smirnov","doi":"10.1016/j.icarus.2025.116584","DOIUrl":"10.1016/j.icarus.2025.116584","url":null,"abstract":"<div><div>In this study, a large-scale numerical investigation of resonant objects in the Neptune region is presented, focusing on both two-body and three-body mean-motion resonances (MMRs). Two separate simulations were conducted to identify resonant populations and quantify their prevalence.</div><div>In Simulation 1, two-body MMRs with Uranus and Neptune up to the resonant order <span><math><mrow><mi>q</mi><mo>≤</mo><mn>10</mn></mrow></math></span>, as well as three-body MMRs involving both planets up to the order <span><math><mrow><mi>q</mi><mo>≤</mo><mn>6</mn></mrow></math></span>, were examined. Using automated resonance classification techniques, it was found that 42.1% of objects are resonant, increasing to 58.2% when including controversial cases. This is significantly higher than the resonant fraction observed in the main asteroid belt. The results confirm that two-body MMRs with Neptune dominate, with a smaller but significant fraction of three-body resonances and two-body resonances with Uranus.</div><div>In Simulation 2, the analysis was extended to higher-order (<span><math><mrow><mi>q</mi><mo>≤</mo><mn>20</mn></mrow></math></span>) and high-integer-coefficient (<span><math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>≤</mo><mn>50</mn></mrow></math></span>) two-body resonances with Neptune, testing whether previously classified non-resonant objects might belong to higher-order MMRs. This second simulation revealed an additional 108 resonances and 104 new confirmed resonant objects, bringing the total fraction of resonant asteroids in the region to 49.3% confirmed cases and 65.1% with controversial cases included. Many new two-body MMRs with Neptune are found. Notably, some objects were found to be trapped in multiple resonances simultaneously.</div><div>These results demonstrate that MMRs play an important role in shaping the trans-Neptunian region, with an overall resonance fraction more than three times higher than in the main asteroid belt. All objects in this region may be in fact resonant.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"436 ","pages":"Article 116584"},"PeriodicalIF":2.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}