Icarus最新文献

{"title":"A novel gravitational inversion method for small celestial bodies based on geodesyNets","authors":"Yabo Duan ,&nbsp;Kefei Zhang ,&nbsp;Zhi Yin ,&nbsp;Shubi Zhang ,&nbsp;Huaizhan Li ,&nbsp;Suqin Wu ,&nbsp;Nanshan Zheng ,&nbsp;Chaofa Bian ,&nbsp;Longjiang Li","doi":"10.1016/j.icarus.2025.116525","DOIUrl":"10.1016/j.icarus.2025.116525","url":null,"abstract":"<div><div>A comprehensive understanding of the internal structure of small celestial bodies is essential for elucidating their formation and evolutionary processes. However, the current observational techniques are severely limited in their ability to effectively probe the structure of small celestial bodies, thereby rendering the method of gravitational inversion the primary means of inferring internal structures. This study, grounded on the model architecture of geodesyNets, introduced a novel method that utilizes gravitational field data to infer the internal density distribution of small celestial bodies. Similar to geodesyNets, by leveraging principles of implicit neural representations (INRs), a deep neural networks (DNN) architecture based on self-supervised learning was developed. This proposed method involved meticulous optimization of hyperparameters, gravitational calculation strategy, activation functions, and loss functions tailored to the specific requirements of gravitational inversion for small celestial bodies. An inversion analysis was conducted on the CERES70E gravitational field model of the dwarf planet Ceres employing this method as a case study, revealing a two-layer internal structure. Moreover, gravitational inversion studies were conducted on simulated small bodies to evaluate the performance of various loss functions, activation functions, hyperparameters, and shape models on the precision of the inferred density fields. The results of these cases provided corroboration for the reliability of the inferred two-layer structural model for Ceres.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116525"},"PeriodicalIF":2.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511347","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":"Formation of steep-sided domes on Venus via eruption of high crystallinity magmas","authors":"R. Cao ,&nbsp;L.M. Saper ,&nbsp;G.D. Bromiley ,&nbsp;P.M. Antoshechkina ,&nbsp;S. Law","doi":"10.1016/j.icarus.2025.116524","DOIUrl":"10.1016/j.icarus.2025.116524","url":null,"abstract":"<div><div>Steep-sided domes are distinctive volcanic landforms on Venus inferred to form by the eruption of highly viscous magma. However, mechanisms responsible for the formation of steep-sided domes remain unclear and the subject of debate. Here we use the rhyolite-MELTS algorithm to constrain the range of magma compositions produced by fractional crystallisation and remelting of Venusian crust, based on rock compositions derived from Venera 13 (alkaline basalt) and Venera 14 (sub-alkaline basalt) lander data. We then calculate liquid-only and liquid plus crystal magma viscosities and compare results to physical models which propose critical minimum viscosities required to form Venusian steep-sided domes. Extensive (&gt;85–90 %) fractionation of Venera 13-based compositions results in the highest viscosity liquids in our models of 9.3 × 10⁸ Pa·s. However, fractional crystallisation and crustal remelting alone is unable to produce liquids with viscosities required to account for formation of steep-sided domes. The intrinsic effect of H₂O by acting as a network modifier in reducing liquid viscosity is more significant than the indirect increases in liquid viscosity caused by modifying phase relations and magma compositions, such as the increase in SiO₂ content. Regardless, even if complete degassing of initially H₂O-saturated magmas is invoked, modelled liquid-only viscosities are still insufficient to account for formation of steep-sided domes. Instead, we find that magmas with high crystal contents, typically &gt;60 vol%, are required to produce sufficiently viscous magmas, a value relatively independent of liquid composition and viscosity parameterisation. Rare terrestrial examples of similarly crystal-rich lava flows and volcanic domes require processes such as rapid degassing-induced crystallisation or fault-controlled mechanisms to accumulate such high crystallinity.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116524"},"PeriodicalIF":2.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509737","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":"Time scales for Co-orbital Cycles of Venus Trojans Asteroids","authors":"V. Carruba ,&nbsp;S. Di Ruzza ,&nbsp;G. Caritá ,&nbsp;S. Aljbaae ,&nbsp;R.C. Domingos ,&nbsp;M. Huaman ,&nbsp;R.A.N. Araujo ,&nbsp;D.C. Mourão ,&nbsp;A.A. Alves ,&nbsp;E.M.D.S. Delfino ,&nbsp;V.R. Silva","doi":"10.1016/j.icarus.2025.116508","DOIUrl":"10.1016/j.icarus.2025.116508","url":null,"abstract":"<div><div>Co-orbital asteroids are asteroids locked in a 1:1 mean-motion resonance with a planet. The mechanism of capture of these objects into their current resonant configuration can shed light on the origin and evolution of asteroids and the whole Solar System. Terrestrial planets’ co-orbital configurations include retrograde satellite orbits (RS), tadpole orbits (T) around the Lagrangian equilibrium points L4 or L5, and horseshoe orbits around both L4 and L5 (H). At high eccentricity or inclination, co-orbital configurations may include compounds of T and RS (T-RS, T-RS-T), H and RS (H-RS) orbits, or transitions between distinct co-orbital modes. These instantaneous configurations may change into one another in short time scales, and Venus Trojans may alternate between several of these configurations before being lost to a passing orbit. We define the time between long periods of staying in a passing orbit as a co-orbital cycle. Here, we use digital filtering of the resonant arguments and rolling averages, a calculation used to analyze data points by creating averages of different subsets of the full data set, of the number of close encounters with Venus of a large population of clones of the currently known co-orbitals of Venus to estimate the times of permanence in one or several cycles. The typical duration of a single cycle is <span><math><mrow><mn>12000</mn><mo>±</mo><mn>6000</mn></mrow></math></span> yrs. Some asteroids may experience two or more cycles before finally escaping co-orbital status, remaining in circulating orbits in between cycles. We call these orbital configurations “dormant orbit”. Six of the Venus’ Trojan may become Potentially Hazardous Asteroid (PHA) with Earth in a few thousand of years, and three asteroids, 2020 SB, 524522, and 2020 CL1, have a severe risk of collision.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116508"},"PeriodicalIF":2.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465242","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":"Reassessing the origin and evolution of Ecliptic Comets in the Planet-9 Scenario","authors":"Rafael Ribeiro de Sousa ,&nbsp;Andre Izidoro ,&nbsp;Alessandro Morbidelli ,&nbsp;David Nesvorny ,&nbsp;Othon Cabo Winter","doi":"10.1016/j.icarus.2025.116472","DOIUrl":"10.1016/j.icarus.2025.116472","url":null,"abstract":"&lt;div&gt;&lt;div&gt;A group of newly observed extreme trans-Neptunian objects show an unexpected level of orbital confinement, characterized by an approximate alignment of the orbital angular momentum vectors and apsidal lines. It has been proposed that a yet undiscovered giant planet (named &lt;em&gt;Planet-9&lt;/em&gt;,) exists in the outer parts of the solar system and is causing this clustering. Initial studies suggested that Planet-9 could be as massive as 15&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊕&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;. In this mass range, however, this planet tends to strongly interact with scattered disk objects (SDOS; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;50&lt;/mn&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;1000&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; au) and influence the dynamics and the orbits of a population of short period comets known as ecliptic comets. The outcome of this interaction is a population of ecliptic comets with orbital inclinations broadly inconsistent with observations. In this work, we model the formation and long-term dynamical evolution of trans-Neptunian object populations and Oort cloud during the solar system dynamical instability phase considering a revised set of mass and orbital parameters for Planet-9. In our simulation, Planet-9, is assumed to have a mass of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊕&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, a moderately inclined orbit with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;20&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; deg, semi-major axis &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;600&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; au, and orbital eccentricity of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. Our results show that a relatively less massive Planet-9 is broadly consistent with the inclination distribution of trans-Neptunian objects and the observed number of ecliptic comets (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; km) in the solar system. Furthermore, our results indicate that under the influence of Planet-9, distant Kuiper belt objects with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;40&lt;/mn&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;100&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;au&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;200&lt;/mn&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;500&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;au&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; that are significantly inclined, are more likely to be apsidally aligned with the planet rather than anti-aligned, with an anti-aligned-to-aligned population ratio of approximately 0.5-0.7. Objects within this semi-major axis and perihelion range and with orbital inclinations lower than &lt;span&gt;&lt;math&gt;&lt;mo&gt;≲&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt; 20 deg (comparable to that assumed for Planet-9), however, exhibit significan","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116472"},"PeriodicalIF":2.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465170","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":"Radiation sputtering of hydrocarbon ices at Europa-relevant temperatures","authors":"Sankhabrata Chandra,&nbsp;Bryana L. Henderson,&nbsp;Murthy S. Gudipati","doi":"10.1016/j.icarus.2025.116522","DOIUrl":"10.1016/j.icarus.2025.116522","url":null,"abstract":"<div><div>The surfaces of some icy moons, such as Jupiter's moon Europa, are heavily bombarded by energetic particles that can alter the surface materials and affect the composition of its exosphere. Detection of CO₂ on Europa's surface indicate that Europa's interior may be transporting freshly exposed carbon-containing material to the surface. It is unknown whether this CO₂ is a product of radiation of carbon-containing precursors or whether it is present in the initial deposits. Regardless, further radiolysis by high-energy electrons or ions can sputter CO₂ (and organic fragments if present) into Europa's exosphere. In this study, we investigate the radiation sputtering of CO₂ and organic fragments from hydrocarbon water ice mixtures at different Europa-relevant surface temperatures to identify how its sputtering products evolve over time. This study shows that the sputtering of hydrocarbon water ice leads to the production of mostly CO₂, CO, and fragmented hydrocarbons. The onset of sputtered hydrocarbons is immediate, and quickly reaches a steady state, whereas CO₂ and CO are formed more gradually. It is found that higher temperatures cause more sputtering, and that there are some notable differences in the distribution of species that are sputtered at different temperatures, indicating local heterogeneity of sputtering yields depending on the surface temperature.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116522"},"PeriodicalIF":2.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511346","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":"Fast firing technique for Martian regolith simulant: Advancing ISRU capabilities","authors":"Levent Karacasulu ,&nbsp;Alessandro Tomasini ,&nbsp;Cekdar Vakifahmetoglu ,&nbsp;Mattia Biesuz","doi":"10.1016/j.icarus.2025.116521","DOIUrl":"10.1016/j.icarus.2025.116521","url":null,"abstract":"<div><div>In-Situ Resource Utilization (ISRU) approaches hold significant importance in plans for space colonization. This work explores a different ISRU concept applying fast-firing, a robust and well-known industrial process, to Mars regolith simulant (MGS-1). The fast-fired specimens were compared to the ones obtained by conventional sintered under low heating rates. When the holding time at the firing temperature is longer than 15 min, fast-fired specimens exhibited higher density and flexural strength (&gt; 35 MPa) than conventional sintering. For both processes, the bulk density values and the mechanical properties of the regolith compacts were enhanced with increasing dwell time. This was attributed to higher heating rates changing the densification/crystallization kinetics involving the basalt glass in the regolith composition. Specifically, high heating rate promotes sintering over crystallization. On these bases, fast firing can be considered a potential candidate for ISRU on Mars.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116521"},"PeriodicalIF":2.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of pit craters on asteroids and small bodies: Predictions about the regolith layer and internal structure","authors":"Miguel de Luis ,&nbsp;Laura M. Parro","doi":"10.1016/j.icarus.2025.116514","DOIUrl":"10.1016/j.icarus.2025.116514","url":null,"abstract":"<div><div>In this work, we investigate and compare potential features called pit craters on the surfaces of (951) Gaspra, (243) Ida, (433) Eros, and the Martian moon, Phobos. Pit craters are typically arranges as chains on the surface and appear to be formed by the drainage of overlying loose material into internal voids promoted by fractures, assessing a piece of direct information about the approximate thickness of the regolith layer, and the internal configuration of each small body. Methodologically, we analyzed images taken by Galileo, NEAR Shoemaker, and other Martian rendezvous missions and mapped these geological morphologies across their surfaces. We analyzed pit sizes using Analysis of Variance and looked for correlations in terms of their different intrinsic physical properties. The pit sizes range between 0.034 and 0.971 km and their estimated regolith layers between 100 and 300 m thick for the four bodies. We demonstrated a strong correlation between the mean diameter of these depressions and the density of the body, making possible a linear model to predict the size of pit craters on small bodies to be visited in future missions, such as Deimos or asteroid (16) Psyche. We also proposed an internal fracturing index for these small bodies that shows a strong correlation with each mean body density. The data provided by future missions for different pitted small objects will allow us to validate or reject these models and predictions.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"433 ","pages":"Article 116514"},"PeriodicalIF":2.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474341","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":"Predominance of porphyritic textures in chondrules due to density sorting of precursor materials? Constraints from melting experiments","authors":"Scott A. Whattam","doi":"10.1016/j.icarus.2025.116510","DOIUrl":"10.1016/j.icarus.2025.116510","url":null,"abstract":"<div><div>Although chondrule textures are diverse, the absolute number of texture types is relatively small essentially encompassing cryptocrystalline (glassy) to microcrystalline (radial pyroxene), barred, granular, metallic and porphyritic/micro-porphyritic varieties; and the vast majority (∼70–90 %) of all textures are a variety of porphyritic (e.g., porphyritic olivine,). Textural diversity has been attributed to the influence of many variables, e.g., bulk composition, duration of heating, cooling rate and size of precursor phases. Here, I show experimentally that when charges are heated initially at 1550 °C that differences in the bulk compositions have an enormous effect on ultimate texture. I construct several bulk compositions by mixing varied quantities of olivine with plagioclase and pyroxene. When synthetic chondrule materials are heated below their liquidus (maximum 1718 °C), the predominant texture is porphyritic if olivine (liquidus of ∼1844 °C) is abundant. If more easily fusible dust (En + An liquidus of 1429 °C) is abundant, barred and glassy chondrule textures result. Assuming amoeboid olivine aggregates (AOA) are possible precursors, I also replaced olivine by synthetic (pre-sintered) granoblastic olivine aggregates (GOA) and isothermally produced PO chondrule analogs when ‘AOA’ (with En + An) mixtures have Ol: En + An ratios of 99:01 to 30:70, but glass-rich analogs at mixtures with ratios of 20:80 and 10:90. If charges are subsequently cooled at 1000 °C/h to 100 °C/h after an isothermal dwell of 1 h at 1550 °C, PO analogs prevail at ratios of Ol:En + An of 30:70 and (presumably, based on isothermal experiments) higher, barred olivine (BO)-like analogs occur at ratios of 20:80; elongated skeletal hopper olivine (EHO) ensues at ratios of 10:90. Models of chondrule formation have not explained the propensity of PO textures but these experiments suggest simply that the predominance of PO chondrules is largely a function of the abundance of Mg in the chondrule precursors and that the ratio of olivine to dust was high in chondrule precursors. Stratification of chondrule precursors may have occurred before chondrule formation, resulting in a greater volume of denser olivine in the central region and greater volume of less dense, fusible An+En in the periphery. Results are compatible with large chondrule-forming regions with a great variety of chondrules being formed in the same event(s) at the same temperature.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116510"},"PeriodicalIF":2.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The phase- and color-ratio techniques as applied to Dawn images of the dwarf planet Ceres and asteroid (4) Vesta","authors":"Ivan G. Slyusarev ,&nbsp;Valeria V. Rychahova ,&nbsp;Vadym G. Kaydash ,&nbsp;Irina N. Belskaya ,&nbsp;Yuriy G. Shkuratov ,&nbsp;Vasilij G. Shevchenko","doi":"10.1016/j.icarus.2025.116507","DOIUrl":"10.1016/j.icarus.2025.116507","url":null,"abstract":"<div><div>Identification of regolith structure anomalies on atmosphereless Solar System bodies is important as an indicator of the surface changes. With the phase ratio method, we are able to map phase curve slopes and distinguish the areas with different regolith optical roughness. These areas are caused by topographic slope processes, formation of new craters and the possible effects of endogenous processes. Global mapping of asteroid (4) Vesta and the dwarf planet Ceres from two orbits High Altitude Mapping Orbit (HAMO) and Low Altitude Mapping Orbit (LAMO) provide the necessary data for applying the phase-ratio technique to these bodies. Using multispectral images from the Dawn Framing Camera (FC) for the dwarf planet Ceres and the asteroid (4) Vesta, phase-ratio and color-ratio methods were applied for selected areas on surfaces of Vesta (Laelia, Laeta, Aricia, Vibidia) and Ceres (Ahuna Mons, craters Occator, Oxo, Xevioso). The phase-ratio method gives us a good tool for both bodies, Ceres and Vesta, to detect changes in regolith structure associated with mass movement due to slope processes on crater walls and hillsides, as well as with ejecta from the youngest craters.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116507"},"PeriodicalIF":2.5,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445720","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 case for young igneous volcanism in the Terra Sirenum region, Mars","authors":"Shreekumari Patel ,&nbsp;Harish ,&nbsp;S. Vijayan ,&nbsp;M.R. El-Maarry","doi":"10.1016/j.icarus.2025.116512","DOIUrl":"10.1016/j.icarus.2025.116512","url":null,"abstract":"<div><div>In this study, we concentrate on an large field of 73 cones situated on the floor of an unnamed crater centered at 27.6°S, 156.9°W. This crater has been subjected to detailed investigations by at least three different scientific teams, each supporting various hypotheses like sedimentary and igneous volcanism regarding the cones origins. The cone field is circumferentially distributed around a triad of primary fractures, which have instigated the formation of the graben structure within the crater. The crater floor exhibits a variety of geomorphological and stratigraphic units, suggesting that the crater has undergone a complex history of different episodes of geological events, including volcanism, tectonic activity and potential fluvial processes. Cones display one of two broad morphologies: domical cones and pitted cones. The morphometric analysis of the W_CR/W_CO in relation to the Cone width of pitted cones aligns with the trends observed in both terrestrial and Martian scoria cones. However, the morphometric measurements of domical cones deviate from the discernible trends typically seen in igneous volcanic structures, sedimentary formations on Earth, and Martian edifices. The cumulative Size-Frequency Distribution (CSFD) analysis indicates the formation of the cone field in the crater occurred between ∼1.26 Ga and ∼1 Ga, corresponding to the Mid-Amazonian epoch. Spectral analysis of the crater floor units indicates the presence of kaolinite, along with low-calcium and high-calcium pyroxene minerals, which could potentially be a marker of volcanic as well as aqueous activities. However, the spectral signature of high-calcium pyroxene in the cone-field bearing crater unit suggests a recent igneous volcanic origin. This study highlights the complex geological history of the unnamed crater, with spectral and morphometric analyses suggesting a likely igneous volcanic origin for the cones amidst evidence of tectonic and aqueous activity.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"432 ","pages":"Article 116512"},"PeriodicalIF":2.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429606","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}