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Observability of radio reflections from exoplanet ionospheres with next generation radio telescopes 用新一代射电望远镜观测系外行星电离层的射电反射
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-26 DOI: 10.1016/j.icarus.2025.116708
Bhavesh Jaiswal , Nirupam Roy
{"title":"Observability of radio reflections from exoplanet ionospheres with next generation radio telescopes","authors":"Bhavesh Jaiswal ,&nbsp;Nirupam Roy","doi":"10.1016/j.icarus.2025.116708","DOIUrl":"10.1016/j.icarus.2025.116708","url":null,"abstract":"<div><div>Much has been learned about exoplanets and their atmospheres in the last three decades with the help of highly sensitive optical telescopes. Limited observations using X-ray telescopes have revealed the presence of ionospheres with very high density plasma around the hot Jupiter HD189733b. Owing to high density, the cutoff frequency of this plasma would lie in the range of few GHz. As the planet goes around the star, we suggest it might be possible to capture the stellar radio emission reflected from the ionosphere of the planet. We find that the reflected spectrum has a slope which is representative of the plasma density profile of the ionosphere and has a cutoff frequency. After investigating the reflection and free-free absorption process in the ionosphere, we find that this reflected signal, though feeble, can be captured by very sensitive radio telescopes operating in the low frequency range. We estimate the reflected signal from the ionosphere of a hot Jupiter and find that the flux ratio of the planet to the star are about <span><math><mrow><mo>∼</mo><mn>0</mn><mo>.</mo><mn>01</mn><mtext>%</mtext></mrow></math></span>. In the view of development of facilities like Square Kilometer Array, it might be possible to capture the reflected radio signal from the ionosphere and constrain the thermal state of the ionosphere.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116708"},"PeriodicalIF":2.5,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144564033","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}
引用次数: 0
Contribution of multiple scattering to the Lyman alpha radiance distribution in cometary comae 多重散射对彗星中莱曼α辐射分布的贡献
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-26 DOI: 10.1016/j.icarus.2025.116720
Yudai Suzuki , Kazuo Yoshioka , Kei Masunaga , Hideyo Kawakita , Yoshiharu Shinnaka , Go Murakami , Tomoki Kimura , Fuminori Tsuchiya , Atsushi Yamazaki , Ichiro Yoshikawa
{"title":"Contribution of multiple scattering to the Lyman alpha radiance distribution in cometary comae","authors":"Yudai Suzuki ,&nbsp;Kazuo Yoshioka ,&nbsp;Kei Masunaga ,&nbsp;Hideyo Kawakita ,&nbsp;Yoshiharu Shinnaka ,&nbsp;Go Murakami ,&nbsp;Tomoki Kimura ,&nbsp;Fuminori Tsuchiya ,&nbsp;Atsushi Yamazaki ,&nbsp;Ichiro Yoshikawa","doi":"10.1016/j.icarus.2025.116720","DOIUrl":"10.1016/j.icarus.2025.116720","url":null,"abstract":"<div><div>Observations of hydrogen Lyman Alpha (Ly-α) radiance distribution in cometary comae are important to deduce water production rates and understand the kinetics of coma gases. Here, we constructed a radiative transfer model including multiple scattering processes to reproduce Ly-α radiance distributions in cometary comae observed by the Hisaki satellite. Using the established model, we found that multiple scatterings should be considered when the hydrogen column density exceeds ∼3 × 10<sup>12</sup> /cm<sup>2</sup>. Additionally, as deuterium Ly-α is almost optically thin unlike hydrogen Ly-α, the deuterium-to‑hydrogen (D/H) Ly-α radiance ratio was found to increase in inner comae. In the end, we calculated the Ly-α radiance profile expected to be observed by the Hydrogen Imager onboard the Comet Interceptor spacecraft. Overall, we quantitatively showed that it is necessary to consider multiple scattering when evaluating activities and D/H ratios of active comets with water production rates over 10<sup>29</sup> /s.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116720"},"PeriodicalIF":2.5,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523495","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}
引用次数: 0
Improved measurement of radar meteor shower mass indices 改进雷达流星雨质量指数的测量方法
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-25 DOI: 10.1016/j.icarus.2025.116652
Yung E. Kipreos , Althea V. Moorhead , Peter G. Brown , Margaret Campbell-Brown , William J. Cooke
{"title":"Improved measurement of radar meteor shower mass indices","authors":"Yung E. Kipreos ,&nbsp;Althea V. Moorhead ,&nbsp;Peter G. Brown ,&nbsp;Margaret Campbell-Brown ,&nbsp;William J. Cooke","doi":"10.1016/j.icarus.2025.116652","DOIUrl":"10.1016/j.icarus.2025.116652","url":null,"abstract":"<div><div>Measurements of meteor radar-derived mass indices are known to be contaminated by sporadic meteoroids (Pokorný and Brown 2016). This leads to overestimated values for the mass index and typically inflates associated meteoroid fluxes. Here we apply a novel mixing model approach to retroactively remove sporadic contamination. This technique, previously applied to the Daytime Sextantid meteor shower (Kipreos et al. 2022), is adapted to a wider suite of meteor showers.</div><div>Applying this mixing model to the strongest meteor shower detected by the Canadian Meteor Orbit Radar (CMOR), namely the Geminids, we calculate an uncontaminated differential mass index of 1.51 at a CMOR limiting mass of 10<sup>−7</sup> kg for the stream at its maximum activity. Additionally, we extend this method to eighteen radar-detected showers in total (ARI, BTA, DRA, DSX, ETA, GEM, NIA, NOC, NOO, OCE, ORI, OSE, PCA, QUA, SDA, TCB, XCB, ZPE) and find mass index values ranging from 1.45–1.79, lower than previous estimates.</div><div>Meteor showers can pose a substantial meteoroid impact risk to spacecraft and astronauts, with mitigation procedures sometimes being required. A shower’s meteoroid risk assessment uses the mass index of that shower, so more accurate shower mass indices, calculated using the mixing model, lead to more accurate meteoroid risk assessments. By utilizing the uncontaminated mass indices of the eighteen most significant meteor showers for satellite impact risk, we re-assess the risk level posed by each, based on the framework from Moorhead et al. (2024a). As a result, the impact risk levels of six showers have been revised downward. Since mitigation procedures require resources such as fuel, time, and operational opportunities, improving impact risk accuracy allows for more efficient mission planning and execution.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116652"},"PeriodicalIF":2.5,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653205","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}
引用次数: 0
Gas permeability of BP-1 lunar regolith simulant at sub-atmospheric pressures BP-1月球风化模拟物在亚大气压下的气体渗透性
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-24 DOI: 10.1016/j.icarus.2025.116703
D.P. Batcheldor , J.G. Mantovani , A.R. Atkins , B.A. Kemmerer , A.G. Langton
{"title":"Gas permeability of BP-1 lunar regolith simulant at sub-atmospheric pressures","authors":"D.P. Batcheldor ,&nbsp;J.G. Mantovani ,&nbsp;A.R. Atkins ,&nbsp;B.A. Kemmerer ,&nbsp;A.G. Langton","doi":"10.1016/j.icarus.2025.116703","DOIUrl":"10.1016/j.icarus.2025.116703","url":null,"abstract":"<div><div>The risks to lunar surface assets from high-velocity regolith ejecta particle streams have significant implications for the sustainable human exploration of the lunar surface. Such regolith can result from lander engine plume-surface interactions. Consequently, the gas permeability of lunar regolith must be understood for precise plume surface interaction ejecta acceleration models. Motivated by these risks, and with the goal of supplying future plume surface interaction models with improved input parameters, the objective of this study is to understand the gas permeability of lunar regolith simulant BP-1 at sub-atmospheric pressures while considering density and moisture content variations. The Regolith Gas Permeability Tester (REGAPT) presented here is a purpose built transparent permeameter that allows the flow of gas to be controlled through the BP-1 once the whole system has reached pressures below 130 Pa. Results from REGAPT demonstrate a range in BP-1 gas permeability from <span><math><mrow><mn>0</mn><mo>.</mo><mn>4</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>13</mn></mrow></msup><mspace></mspace><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mn>1</mn><mo>.</mo><mn>9</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>13</mn></mrow></msup><mspace></mspace><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>. Higher densities and lower porosities reduce permeability as expected. Outgassing from residual moisture in BP-1 is found to bias gas permeability measurements. It is therefore important to carefully control the moisture content of lunar regolith simulants in experimental studies that involve gas flow, such as those investigating the effects of plume surface interactions.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116703"},"PeriodicalIF":2.5,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501864","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}
引用次数: 0
A statistical approach to quantifying uncertainty in meteoroid physical properties 一种量化流星体物理性质不确定性的统计方法
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-23 DOI: 10.1016/j.icarus.2025.116698
Maximilian Vovk, Denis Vida, Peter G. Brown
{"title":"A statistical approach to quantifying uncertainty in meteoroid physical properties","authors":"Maximilian Vovk,&nbsp;Denis Vida,&nbsp;Peter G. Brown","doi":"10.1016/j.icarus.2025.116698","DOIUrl":"10.1016/j.icarus.2025.116698","url":null,"abstract":"<div><h3>Importance:</h3><div>Meteoroid bulk density is a critical value required for assessing impact risks to spacecraft, informing shielding and mission design.</div></div><div><h3>Research Gap:</h3><div>Direct bulk density measurements for sub-millimeter to millimeter-sized meteoroids are difficult, often relying on forward modeling without robust uncertainty estimates. Methods based solely on select observables can overlook noise-induced biases and non-linear relations between physical parameters.</div></div><div><h3>Objective:</h3><div>This study aims to automate the inversion of meteoroid physical parameters from optical meteor data, focusing on bulk density and its associated uncertainties.</div></div><div><h3>Methodology:</h3><div>We compare an observables-based selection method (PCA) with an RMSD-based approach used to select among millions of ablation model runs using full light and deceleration curves as constraints. After validating both approaches on six synthetic test cases, we apply them to two Perseid meteors recorded by high sensitivity Electron-Multiplied CCD (EMCCD) cameras and high precision mirror-tracked meteors detected by the Canadian Automated Meteor Observatory (CAMO).</div></div><div><h3>Key Findings:</h3><div>Our results show that relying only on observables, as in the PCA approach can converge to wrong solutions and can yield unphysical solutions. In contrast, the RMSD-based method offers more reliable density constraints, particularly for bright and strongly decelerating meteor. Small relative measurement precision in brightness and lag relative to the full range of observed lag and luminosity is the key to tight solution</div></div><div><h3>Implications:</h3><div>We provide the first objectively derived uncertainty bounds for the physical properties of meteoroids. Our approach solves the solution degeneracy problem inherent in forward modeling of meteors. This strategy can be generalized to other showers, paving the way for improved meteoroid models and enhanced spacecraft safety.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116698"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144514370","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}
引用次数: 0
Characteristics of the Shackleton-de Gerlache ridge and implications for lunar south polar geology and future sampling activities Shackleton-de Gerlache脊的特征及其对月球南极地质和未来采样活动的影响
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-23 DOI: 10.1016/j.icarus.2025.116719
A.J. Gawronska , S.J. Boazman
{"title":"Characteristics of the Shackleton-de Gerlache ridge and implications for lunar south polar geology and future sampling activities","authors":"A.J. Gawronska ,&nbsp;S.J. Boazman","doi":"10.1016/j.icarus.2025.116719","DOIUrl":"10.1016/j.icarus.2025.116719","url":null,"abstract":"<div><div>The geology of the Shackleton-de Gerlache ridge at the lunar south pole is of interest to the planetary community due to its geologic history, ancient age, illumination conditions, and polar location. The precise origin, evolution, and lithology of the ridge is currently poorly understood, but data recently collected by instrumentation like ShadowCam provides new information that will support our understanding of the lunar highlands and the effects of impact cratering in this polar location. In this work, we evaluate the topographic extent of the ridge, and assess its physical and chemical makeup as exposed within the Shackleton crater. We find that the ridge is adorned by four peaks with saddles between them and a berm feature formed nearby Spudis crater. We also find that boulder distribution inside Shackleton indicates ongoing mass wasting processes, and that boulder density is not constant along the cross section of the ridge. Changing boulder distribution densities appear to correspond with varying modal mineralogy, potentially indicating that the ridge presents overturned layered material, or is brecciated. Ridge characteristics are consistent with a crustal origin where materials were deposited by the South Pole-Aitken impact. Future work should continue evaluating the subsurface exposed by large craters in this region to better understand the geologic evolution of similar ridges prior to exploration efforts.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116719"},"PeriodicalIF":2.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517825","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}
引用次数: 0
Multiple thermal events during 4350–3920 Ma recorded in a single lunar meteorite Northwest Africa 4485 在非洲西北部的一块月球陨石上记录了4350-3920 Ma的多个热事件
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-22 DOI: 10.1016/j.icarus.2025.116715
Tomoko Arai , Takayuki Tomiyama , Takafumi Niihara , Tatsunori Yokoyama , Miwa Yoshitake , Hiroshi Kaiden , Keiji Misawa , Anthony J. Irving
{"title":"Multiple thermal events during 4350–3920 Ma recorded in a single lunar meteorite Northwest Africa 4485","authors":"Tomoko Arai ,&nbsp;Takayuki Tomiyama ,&nbsp;Takafumi Niihara ,&nbsp;Tatsunori Yokoyama ,&nbsp;Miwa Yoshitake ,&nbsp;Hiroshi Kaiden ,&nbsp;Keiji Misawa ,&nbsp;Anthony J. Irving","doi":"10.1016/j.icarus.2025.116715","DOIUrl":"10.1016/j.icarus.2025.116715","url":null,"abstract":"<div><div>A lunar meteorite Northwest Africa (NWA) 4485 is a KREEP (potassium, rare earth elements and phosphorus)-rich polymict breccia, likely paired with NWA 4472. NWA 4485 includes mm-sized lithic clasts with variable textures and modal abundances. The lithic clasts share features with KREEP basalts, and consist dominantly of moderately Mg-rich pyroxene and less calcic plagioclase than those in the Apollo 17 KREEPy basalt with zircon and phosphates. Uranium‐thorium‐lead isotopic studies on zircon and baddeleyite in the lithic clasts and matrix of NWA 4485 revealed that the <sup>207</sup>Pb--<sup>206</sup>Pb age spectrum (4350–3920 Ma) is compatible with that for apatite in the paired NWA 4472, broadly covering the ages of zircons in Apollo polymict breccia samples from multiple landing sites. The presence of a 4160 Ma zircon in a millimeter-sized lithic clast, a core of 4210 Ma in a detrital zircon with multiple rims of ∼3960 Ma, and an individual zircon grain of 4350 Ma in the matrix clearly indicates that they are products of pre-mare multiple KREEP-related magmatism, predating the lunar cataclysm (∼3900–4000 Ma).</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116715"},"PeriodicalIF":2.5,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523494","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}
引用次数: 0
The blinking crystallinity of Europa: A competition between irradiation and thermal alteration 闪烁的木卫二结晶:辐射与热蚀变的竞争
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-20 DOI: 10.1016/j.icarus.2025.116700
Cyril Mergny , Frédéric Schmidt , Félix Keil
{"title":"The blinking crystallinity of Europa: A competition between irradiation and thermal alteration","authors":"Cyril Mergny ,&nbsp;Frédéric Schmidt ,&nbsp;Félix Keil","doi":"10.1016/j.icarus.2025.116700","DOIUrl":"10.1016/j.icarus.2025.116700","url":null,"abstract":"<div><div>The surface of Europa experiences a competition between thermally-induced crystallization and radiation-induced amorphization processes, leading to changes of its crystalline structure. The non-linear crystallization and temperature-dependent amorphization rates, incorporating ions, electrons and UV doses, are integrated into our multiphysics surface model (MSM) <em>LunaIcy</em>, enabling simulations of these coupled processes on icy moons.</div><div>Thirty simulations spanning <span><math><mrow><mn>100</mn><mspace></mspace><mn>000</mn><mspace></mspace><mstyle><mi>y</mi><mi>e</mi><mi>a</mi><mi>r</mi><mi>s</mi></mstyle></mrow></math></span>, covering the full ranges of albedo and latitude values on Europa, explore the competition between crystallization and irradiation. This is the first modeling of depth-dependent crystallinity profiles on icy moons. The results of our simulations are coherent with existing spectroscopic studies of Europa, both methods showing a primarily amorphous phase at the surface, followed by a crystalline phase after the first millimeter depth. Our method provides quantitative insights into how various parameters found on Europa can influence the subsurface crystallinity profiles.</div><div>Interpolating upon our simulations, we have generated crystallinity maps of Europa showing highly crystalline ice near the equator, amorphous ice at the poles, and a mix of the two at mid-latitudes. Regions/depths with balanced competition between crystallization and amorphization rates are of high interest due to their periodic fluctuations in crystalline fraction. Our interpolated map reveals periodic variations, with seasonal amplitudes reaching up to 35% of crystalline fraction. These variations could be detected through spectroscopy, and we propose a plan to observe them in forthcoming missions.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116700"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489759","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}
引用次数: 0
Phosphates reveal high pH ocean water on Enceladus 磷酸盐表明土卫二上的海水pH值很高
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-20 DOI: 10.1016/j.icarus.2025.116717
Christopher R. Glein, Ngoc Truong
{"title":"Phosphates reveal high pH ocean water on Enceladus","authors":"Christopher R. Glein,&nbsp;Ngoc Truong","doi":"10.1016/j.icarus.2025.116717","DOIUrl":"10.1016/j.icarus.2025.116717","url":null,"abstract":"<div><div>Enceladus offers our best opportunity for exploring the chemistry of an ocean on another world. Here, we perform geochemical modeling to show how the distribution of phosphate species found in ice grains from Enceladus's plume provides a very straightforward constraint on the pH of the host solution. The ratio of HPO<sub>4</sub>/PO<sub>4</sub> species serves as a pH indicator. We find evidence of moderately alkaline water (pH 10.1–11.6)—significantly more alkaline than current estimates (∼8–9) of the pH of Enceladus's ocean. Nevertheless, the pH range from phosphates is consistent with the CO<sub>2</sub>/H<sub>2</sub>O ratio measured in the plume if CO<sub>2</sub> exsolves from ocean water according to its equilibrium solubility. A simple energy balance can be used to quantify volatile fractionation during gas transport inside Enceladus's tiger stripes; we deduce that ∼83 % of water vapor is removed as ice during transport between the liquid-vapor interface and where gases exit the subsurface. We also explore how CO<sub>2</sub> degassing may lead to an increase in the apparent pH of ocean water. We generate maps of allowed combinations of pH and dissolved inorganic carbon concentration of the source water for a wide range of scenarios. Our preferred interpretation, constrained by the observed heat flux, implies minimal CO<sub>2</sub> degassing from ocean water. Hence, the pH recorded by phosphates should closely approximate that of the ocean; our best estimate is pH ∼10.6. Such a high pH seems to reflect a major role of silicates enriched in Na, Mg, or Fe(II) interacting extensively with ocean water. Silica nanoparticles would not form or would subsequently dissolve if the pH is too high (&gt;10.5). The outgassing model presented here provides a new path to quantify the dissolved concentrations of volatile species.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116717"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144469912","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}
引用次数: 0
The Amundsen-Ganswindt basin: An overlooked lunar peak-ring basin with multiple exploration opportunities Amundsen-Ganswindt盆地:一个被忽视的月球峰环盆地,具有多种勘探机会
IF 2.5 2区 物理与天体物理
Icarus Pub Date : 2025-06-20 DOI: 10.1016/j.icarus.2025.116718
J. Hostrawser, G.R. Osinski
{"title":"The Amundsen-Ganswindt basin: An overlooked lunar peak-ring basin with multiple exploration opportunities","authors":"J. Hostrawser,&nbsp;G.R. Osinski","doi":"10.1016/j.icarus.2025.116718","DOIUrl":"10.1016/j.icarus.2025.116718","url":null,"abstract":"<div><div>The ∼ 355 km diameter Amundsen-Ganswindt impact basin (81°S, 120°E) has been stratigraphically constrained as the oldest large basin in the South Pole-Aitken basin terrane. It partly overlaps the Artemis Exploration Zone, across which it deposited significant volumes of impact ejecta deposits. The basin is highly degraded and partially superposed by the similar-sized Schrödinger peak-ring impact basin, leading previous workers to question whether it contains any remnants of an original peak-ring. We have conducted a detailed geologic study of the Amundsen-Ganswindt basin and evaluated the scientific potential of this ancient structure in the context of global lunar exploration objectives that underpin future crewed and robotic exploration missions to the lunar south polar region. We have mapped the basin at a scale of 1:1,000,000 and identified high-value exploration targets, including remnants of an original peak ring and opportunities to sample this uplifted material. Given its age, both Amundsen-Ganswindt's peak ring and ejecta deposits will contain a high proportion of material from the South Pole-Aitken basin. In addition, material from the Schrödinger peak-ring impact basin — the second youngest basin on the Moon — are also available for sampling. Morphological evidence suggests that the Amundsen-Ganswindt basin influenced the final morphology of Schrödinger's rim and peak ring. The Amundsen-Ganswindt basin is also host to large, accessible permanently shadowed regions with orbital detections of water ice. Thus, we propose that the overlooked Amundsen-Ganswindt basin is an exceptional exploration target for future robotic and human exploration missions.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"441 ","pages":"Article 116718"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517824","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}
引用次数: 0
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