Pub Date : 2025-12-04DOI: 10.1016/j.icarus.2025.116900
Jose A. Perez Chavez , Orenthal J. Tucker , Shane R. Carberry Mogan , Robert E. Johnson , Christopher Blaszczak-Boxe
Direct Simulation Monte Carlo (DSMC) calculations of acoustic gravity wave propagation into the exobase region of a Mars-like atmosphere reveal that radial geometry can reduce wave-driven heating compared to a Cartesian model. We examine two acoustic wave (AW) modes with periods of 11 min (AW1) and 5.5 min (AW2) propagating from 100 to 320 km altitude using a radial molecular kinetics model. The wave-driven heating was reduced by 40–56 % with cycle-averaged temperature gradient decreasing from 9.4 K per scale height H0 to 5.6 K/H0 for AW1 and from 4.4 K/H0 to 1.9 K/H0 for AW2 when accounting for planetary curvature. While the growth in wave density amplitude was attenuated for the 1D radial geometry as well, the heating differences are more pronounced, with both effects driven by geometric spreading accumulating as waves propagate into increasingly rarefied regions. These findings suggest that accounting for curvature effects is crucial when conducting DSMC estimates of acoustic wave contributions to thermospheric heating and atmospheric escape, as Cartesian-based derived counterparts may be overestimated by factors of 1.7–2.3 for these frequencies.
{"title":"Impact of geometry on 1D molecular-kinetics simulations of acoustic-gravity wave propagation into the exosphere","authors":"Jose A. Perez Chavez , Orenthal J. Tucker , Shane R. Carberry Mogan , Robert E. Johnson , Christopher Blaszczak-Boxe","doi":"10.1016/j.icarus.2025.116900","DOIUrl":"10.1016/j.icarus.2025.116900","url":null,"abstract":"<div><div>Direct Simulation Monte Carlo (DSMC) calculations of acoustic gravity wave propagation into the exobase region of a Mars-like atmosphere reveal that radial geometry can reduce wave-driven heating compared to a Cartesian model. We examine two acoustic wave (AW) modes with periods of 11 min (AW1) and 5.5 min (AW2) propagating from 100 to 320 km altitude using a radial molecular kinetics model. The wave-driven heating was reduced by 40–56 % with cycle-averaged temperature gradient <span><math><mfenced><mrow><mi>d</mi><mi>T</mi><mo>/</mo><mi>d</mi><mi>r</mi></mrow></mfenced></math></span> decreasing from 9.4 K per scale height <em>H</em><sub><em>0</em></sub> to 5.6 K/<em>H</em><sub><em>0</em></sub> for AW1 and from 4.4 K/<em>H</em><sub><em>0</em></sub> to 1.9 K/<em>H</em><sub><em>0</em></sub> for AW2 when accounting for planetary curvature. While the growth in wave density amplitude was attenuated for the 1D radial geometry as well, the heating differences are more pronounced, with both effects driven by geometric spreading accumulating as waves propagate into increasingly rarefied regions. These findings suggest that accounting for curvature effects is crucial when conducting DSMC estimates of acoustic wave contributions to thermospheric heating and atmospheric escape, as Cartesian-based derived counterparts may be overestimated by factors of 1.7–2.3 for these frequencies.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116900"},"PeriodicalIF":3.0,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748587","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}
Pub Date : 2025-12-04DOI: 10.1016/j.icarus.2025.116901
Antoine Martinez , Hiroki Karyu , Amanda Brecht , Gabriella Gilli , Sebastien Lebonnois , Takeshi Kuroda , Aurelien Stolzenbach , Francisco González-Galindo , Stephen Bougher , Hitoshi Fujiwara
In the context of future Venusian missions, it is crucial to improve our understanding of Venus upper atmosphere through 3D modeling, notably for spacecraft orbit computation. This study compares three General Circulation Models (GCMs) of the Venusian atmosphere up to the exosphere: the Venus Planetary Climate Model (Venus PCM), the Venus Thermospheric Global Model (VTGCM) and the Tohoku University GCM (TUGCM), focusing on their nominal simulations (e.g. composition, thermal structure and heating/cooling rates). Similarities and discrepancies among them are discussed in this paper, together with data-models comparison. The nominal simulations analyzed in this study fail to accurately reproduce the daytime observations of Pioneer Venus, notably overestimating the exospheric temperature. This is linked to an underestimation of the atomic oxygen (O) abundance in the three GCMs, and suggests the need of additional O production in the thermosphere. The selection of solar spectrum is also the main reason for the discrepancies between the models in terms of temperature dependence on solar activity. A list of recommendations is proposed aiming at improving the modeling of Venus’ upper atmosphere, among them: 1. Standardize the EUV-UV solar spectrum input. 2. Update the near-infrared heating scheme with Venus Express-Era data. 3. Reassess Radiative cooling schemes. 4. Investigate the underestimated atomic Oxygen abundance.
在未来金星任务的背景下，通过三维建模，特别是航天器轨道计算，提高我们对金星高层大气的理解至关重要。本研究比较了金星大气至外逸层的三种大气环流模式（GCMs）：金星行星气候模式（Venus PCM）、金星热层全球模式（Venus Thermospheric Global Model）和东北大学GCM (TUGCM)，重点研究了它们的名义模拟（如成分、热结构和加热/冷却速率）。本文讨论了它们之间的异同，并对数据模型进行了比较。本研究分析的名义模拟不能准确地再现先锋金星白天的观测结果，特别是高估了外层温度。这与三种gcm中原子氧(O)丰度的低估有关，并表明需要在热层中产生额外的O。太阳光谱的选择也是不同模式在温度对太阳活动依赖关系方面存在差异的主要原因。为了改进金星高层大气的建模，提出了一系列建议，其中包括：1。标准化EUV-UV太阳光谱输入。2. 用金星快车时代的数据更新近红外加热方案。3. 重新评估辐射冷却方案。4. 调查被低估的氧原子丰度。
{"title":"Comparison of General Circulation Models of the Venus upper atmosphere","authors":"Antoine Martinez , Hiroki Karyu , Amanda Brecht , Gabriella Gilli , Sebastien Lebonnois , Takeshi Kuroda , Aurelien Stolzenbach , Francisco González-Galindo , Stephen Bougher , Hitoshi Fujiwara","doi":"10.1016/j.icarus.2025.116901","DOIUrl":"10.1016/j.icarus.2025.116901","url":null,"abstract":"<div><div>In the context of future Venusian missions, it is crucial to improve our understanding of Venus upper atmosphere through 3D modeling, notably for spacecraft orbit computation. This study compares three General Circulation Models (GCMs) of the Venusian atmosphere up to the exosphere: the Venus Planetary Climate Model (Venus PCM), the Venus Thermospheric Global Model (VTGCM) and the Tohoku University GCM (TUGCM), focusing on their nominal simulations (e.g. composition, thermal structure and heating/cooling rates). Similarities and discrepancies among them are discussed in this paper, together with data-models comparison. The nominal simulations analyzed in this study fail to accurately reproduce the daytime observations of Pioneer Venus, notably overestimating the exospheric temperature. This is linked to an underestimation of the atomic oxygen (O) abundance in the three GCMs, and suggests the need of additional O production in the thermosphere. The selection of solar spectrum is also the main reason for the discrepancies between the models in terms of temperature dependence on solar activity. A list of recommendations is proposed aiming at improving the modeling of Venus’ upper atmosphere, among them: 1. Standardize the EUV-UV solar spectrum input. 2. Update the near-infrared heating scheme with Venus Express-Era data. 3. Reassess Radiative cooling schemes. 4. Investigate the underestimated atomic Oxygen abundance.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116901"},"PeriodicalIF":3.0,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748589","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}
Pub Date : 2025-11-30DOI: 10.1016/j.icarus.2025.116890
M.I. Galiullin, D.V. Glamazda, E.D. Kuznetsov
The results of our multicolor photometric observations of near-Earth asteroids (NEAs) with the SBG telescope at the Kourovka Astronomical Obervatory of Ural Federal University (KAO UrFU, code 168) are presented. We aimed to estimate several NEA properties — absolute magnitudes, color indices, rotation periods, shapes, and axis ratios. Multicolor photometry was performed in the B, V, R and I filters of the Cousins–Johnson system. Rotation periods were derived using the Lomb–Scargle method.
For the seven asteroids studied, we determined absolute magnitudes ranging from 15.80 to 18.11, measured the B-V color index for (36183) 1999 TX16 as well as the V-R and R-I indices for all targets, found axis ratios a/b between 1.267 and 2.374, and obtained rotation periods between 4 and 9 h. Based on the obtained color indices, we performed a taxonomic classification, and according to our results, all the asteroids belong to the S-complex.
{"title":"Physical properties of seven near-Earth asteroids from photometric observations","authors":"M.I. Galiullin, D.V. Glamazda, E.D. Kuznetsov","doi":"10.1016/j.icarus.2025.116890","DOIUrl":"10.1016/j.icarus.2025.116890","url":null,"abstract":"<div><div>The results of our multicolor photometric observations of near-Earth asteroids (NEAs) with the SBG telescope at the Kourovka Astronomical Obervatory of Ural Federal University (KAO UrFU, code 168) are presented. We aimed to estimate several NEA properties — absolute magnitudes, color indices, rotation periods, shapes, and axis ratios. Multicolor photometry was performed in the <em>B</em>, <em>V</em>, <em>R</em> and <em>I</em> filters of the Cousins–Johnson system. Rotation periods were derived using the Lomb–Scargle method.</div><div>For the seven asteroids studied, we determined absolute magnitudes ranging from 15.80 to 18.11, measured the <em>B-V</em> color index for (36183) 1999 TX16 as well as the <em>V-R</em> and <em>R-I</em> indices for all targets, found axis ratios <em>a/b</em> between 1.267 and 2.374, and obtained rotation periods between 4 and 9 h. Based on the obtained color indices, we performed a taxonomic classification, and according to our results, all the asteroids belong to the S-complex.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116890"},"PeriodicalIF":3.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692531","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}
Pub Date : 2025-11-30DOI: 10.1016/j.icarus.2025.116892
Matteo Dossi , Jamaledin Baniamerian , Sebastian Emanuel Lauro , Barbara Cosciotti , Elisabetta Mattei , Federico Tosi , Elena Pettinelli
We study the dielectric properties of the lunar near-surface across a 1.43 km long 2-D Ground Penetrating Radar (GPR) data set, that was acquired by the still-operational Yutu-2 surface rover as part of the Chang'e-4 lunar mission of 2019. The surveyed area is part of the Eastern Floor of the Von Kármán crater, which is located in the northwestern sector of the South Pole–Aitken Basin, on the far side of the Moon. The total attenuation and intrinsic lost tangent are mapped across the entire GPR profile using time-domain amplitude decay and centroid frequency downshift methods, respectively. The cumulative electromagnetic (EM) velocity distribution is obtained by analyzing 136 automatically tracked hyperbolic diffractions spread across the data set, down to a time-depth of ∼200 ns. The resulting vertical trends within three different sections of the GPR profile are then fitted using the Deming regression, in order to estimate the interval EM velocities in the lunar regolith, and subsequently the average electric permittivities, down to a depth of ∼13 m. The novel EM velocity analysis is designed to account for both the GPR antenna height, possible out-of-plane diffractions, and the radii of the scatterers, all of which can significantly affect the reconstructed cumulative EM velocity distribution. We further compare our inversion results with other lunar subsurface models from the available literature, and critically discuss both the advantages and limitations of the applied methodologies, while also taking into account the expectably less-than-ideal survey conditions of the Chang'e-4 mission.
{"title":"Dielectric properties of the lunar regolith estimated through a combined loss tangent and EM velocity distribution analysis of the Chang'e-4 GPR data set","authors":"Matteo Dossi , Jamaledin Baniamerian , Sebastian Emanuel Lauro , Barbara Cosciotti , Elisabetta Mattei , Federico Tosi , Elena Pettinelli","doi":"10.1016/j.icarus.2025.116892","DOIUrl":"10.1016/j.icarus.2025.116892","url":null,"abstract":"<div><div>We study the dielectric properties of the lunar near-surface across a 1.43 km long 2-D Ground Penetrating Radar (GPR) data set, that was acquired by the still-operational Yutu-2 surface rover as part of the Chang'e-4 lunar mission of 2019. The surveyed area is part of the Eastern Floor of the Von Kármán crater, which is located in the northwestern sector of the South Pole–Aitken Basin, on the far side of the Moon. The total attenuation and intrinsic lost tangent are mapped across the entire GPR profile using time-domain amplitude decay and centroid frequency downshift methods, respectively. The cumulative electromagnetic (EM) velocity distribution is obtained by analyzing 136 automatically tracked hyperbolic diffractions spread across the data set, down to a time-depth of ∼200 ns. The resulting vertical trends within three different sections of the GPR profile are then fitted using the Deming regression, in order to estimate the interval EM velocities in the lunar regolith, and subsequently the average electric permittivities, down to a depth of ∼13 m. The novel EM velocity analysis is designed to account for both the GPR antenna height, possible out-of-plane diffractions, and the radii of the scatterers, all of which can significantly affect the reconstructed cumulative EM velocity distribution. We further compare our inversion results with other lunar subsurface models from the available literature, and critically discuss both the advantages and limitations of the applied methodologies, while also taking into account the expectably less-than-ideal survey conditions of the Chang'e-4 mission.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116892"},"PeriodicalIF":3.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692530","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}
We aim to evaluate the detectability of spectral slope differences — i.e., the phase coloring effect — in asteroid spectro-photometric surveys, and to assess the potential of current and forthcoming datasets for investigating color-related phenomena in asteroids. We estimated the phase coloring effect expected to be observable in spectro-photometric surveys (ATLAS, ZTF, SDSS, LSST, VISTA, and Euclid) by combining meteorite reflectance spectra obtained at various phase angles with the transmission curves of each survey’s filters. Subsequently, we conducted extensive simulations to determine the uncertainties in color indices and phase-curve parameters necessary to detect coloring variations at the estimated uncertainty levels. Finally, we analyzed actual survey data to assess how many objects meet these criteria and examined the wavelength dependence and prevalence of reddening and bluening effects in the broader asteroid population. Analysis of meteorite spectra indicates that spectral slope variations in spectrophotometric survey data are at most few % per 100 nm. Simulations show that detecting such changes requires color index uncertainties of 0.05–0.2 mag (depending on the survey) and phase curve parameter uncertainties (, , ) of 0.05. These conditions are met by only a small fraction of surveyed objects, making reliable detection of the phase coloring effect challenging. Thus, only statistical analyses of nominal solutions can reveal population-level trends. Our results show that reddening is more common than bluening, especially at higher phase angles. Phase curve parameters wavelength-dependency is observed in several types (B, C, X, S, V) across different surveys. Reliable detection of spectral slope variations for individual objects from survey data is highly challenging due to the need for very low uncertainties in both color indices and phase curve parameters. Progress will require surveys with widely separated filters, near-simultaneous multi-band observations to reduce color uncertainties, well-sampled phase curves at low phase angles, and precise methods for constraining phase curve parameters. While population-level trends can be studied using nominal solutions, such analyses must be interpreted with caution due to the high uncertainties inherent in the sparse survey data.
{"title":"Detectability of asteroid phase coloring based on phase curves obtained from large spectro-photometric surveys","authors":"Milagros Colazo , Dagmara Oszkiewicz , Patrycja Poźniak , Alvaro Alvarez-Candal , Benoit Carry , Ola Wenda , Wiktoria Stefanowska","doi":"10.1016/j.icarus.2025.116891","DOIUrl":"10.1016/j.icarus.2025.116891","url":null,"abstract":"<div><div>We aim to evaluate the detectability of spectral slope differences — i.e., the phase coloring effect — in asteroid spectro-photometric surveys, and to assess the potential of current and forthcoming datasets for investigating color-related phenomena in asteroids. We estimated the phase coloring effect expected to be observable in spectro-photometric surveys (ATLAS, ZTF, SDSS, LSST, VISTA, and Euclid) by combining meteorite reflectance spectra obtained at various phase angles with the transmission curves of each survey’s filters. Subsequently, we conducted extensive simulations to determine the uncertainties in color indices and phase-curve parameters necessary to detect coloring variations at the estimated uncertainty levels. Finally, we analyzed actual survey data to assess how many objects meet these criteria and examined the wavelength dependence and prevalence of reddening and bluening effects in the broader asteroid population. Analysis of meteorite spectra indicates that spectral slope variations in spectrophotometric survey data are at most few % per 100 nm. Simulations show that detecting such changes requires color index uncertainties of <span><math><mo>∼</mo></math></span>0.05–0.2 mag (depending on the survey) and phase curve parameter uncertainties (<span><math><msub><mrow><mi>G</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>G</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>G</mi></mrow><mrow><mn>12</mn></mrow></msub></math></span>) of <span><math><mo>∼</mo></math></span>0.05. These conditions are met by only a small fraction of surveyed objects, making reliable detection of the phase coloring effect challenging. Thus, only statistical analyses of nominal solutions can reveal population-level trends. Our results show that reddening is more common than bluening, especially at higher phase angles. Phase curve parameters wavelength-dependency is observed in several types (B, C, X, S, V) across different surveys. Reliable detection of spectral slope variations for individual objects from survey data is highly challenging due to the need for very low uncertainties in both color indices and phase curve parameters. Progress will require surveys with widely separated filters, near-simultaneous multi-band observations to reduce color uncertainties, well-sampled phase curves at low phase angles, and precise methods for constraining phase curve parameters. While population-level trends can be studied using nominal solutions, such analyses must be interpreted with caution due to the high uncertainties inherent in the sparse survey data.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116891"},"PeriodicalIF":3.0,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145645722","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}
Pub Date : 2025-11-29DOI: 10.1016/j.icarus.2025.116888
Hannu Savijärvi , German Martinez , Mark Paton , Jouni Polkko , Joonas Leino , Ari-Matti Harri
The downwelling longwave radiation from the atmosphere (LWD) measured by the Perseverance rover was compared to those from a local single column model (SCM) on Ls 71o, MY 36 (sol 140) and from the GCM-based Mars Climate Database (MCD). SCM with surface temperatures fitted to the observed leads here to too high LWD, whereas with air temperatures and moistures at 1.5 m fitted to those observed the model-LWD aligns better with observations, being insensitive to dust profiles. MCD indicated Hadley cell uplift and an ice cloud at 10–20 km. Introducing MCD-like uplift and its water column (11 pr-μm), SCM reproduced the cloud, however with too high LWD. Use of the observed 4 pr-μm led instead to a thin morning cloud, adding a small morning increase to the model-LWD as observed, although too early. The cloud thus appears to be quite thin over Jezero during MY 36, consistently with EMIRS observations.
{"title":"Aspects of thermal radiation from the atmosphere in Jezero crater, Mars, through observations and model results: An aphelion case study","authors":"Hannu Savijärvi , German Martinez , Mark Paton , Jouni Polkko , Joonas Leino , Ari-Matti Harri","doi":"10.1016/j.icarus.2025.116888","DOIUrl":"10.1016/j.icarus.2025.116888","url":null,"abstract":"<div><div>The downwelling longwave radiation from the atmosphere (LWD) measured by the Perseverance rover was compared to those from a local single column model (SCM) on Ls 71<sup>o</sup>, MY 36 (sol 140) and from the GCM-based Mars Climate Database (MCD). SCM with surface temperatures fitted to the observed leads here to too high LWD, whereas with air temperatures and moistures at 1.5 m fitted to those observed the model-LWD aligns better with observations, being insensitive to dust profiles. MCD indicated Hadley cell uplift and an ice cloud at 10–20 km. Introducing MCD-like uplift and its water column (11 pr-μm), SCM reproduced the cloud, however with too high LWD. Use of the observed 4 pr-μm led instead to a thin morning cloud, adding a small morning increase to the model-LWD as observed, although too early. The cloud thus appears to be quite thin over Jezero during MY 36, consistently with EMIRS observations.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116888"},"PeriodicalIF":3.0,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692532","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}
Pub Date : 2025-11-27DOI: 10.1016/j.icarus.2025.116889
Mu-Han Yang , Qian W.L. Zhang , Richard W. Carlson , Bi-Wen Wang , Dongjian Ouyang , Qiu-Li Li
The Moon's formation time is a key factor for understanding the early evolution of the Earth-Moon system. The lunar magma ocean (LMO) model explains how cumulate mafic materials crystallizing from the LMO form the source of mare basalts (SMB). The SMB with an equilibrated Sm–Nd system is considered to share an identical initial Pb isotope signature (PbSMB). Because Pb is volatile while U is refractory, PbSMB can provide constraints for the timing of volatile depletion, most likely dating the time of Moon formation by a giant impact. The PbSMB is a link between the initial Pb composition of lunar mare basalts and the Moon's early evolution via a two-stage Pb evolution model that provides a simplified but informative framework. Using four mare basalts with well-constrained ages and initial Pb isotopic compositions, we estimate the Moon's formation time at Ma and the SMB formation time at Ma, which we regard as the preferred solution within the statistical framework of the model. Our modelling strategy also facilitates the dating of mare basalt fragments lacking Zr-bearing minerals using the initial Pb isotopic compositions constrained by U-poor minerals.
{"title":"The moon's formation time recorded in lunar mare basalts","authors":"Mu-Han Yang , Qian W.L. Zhang , Richard W. Carlson , Bi-Wen Wang , Dongjian Ouyang , Qiu-Li Li","doi":"10.1016/j.icarus.2025.116889","DOIUrl":"10.1016/j.icarus.2025.116889","url":null,"abstract":"<div><div>The Moon's formation time is a key factor for understanding the early evolution of the Earth-Moon system. The lunar magma ocean (LMO) model explains how cumulate mafic materials crystallizing from the LMO form the source of mare basalts (SMB). The SMB with an equilibrated Sm–Nd system is considered to share an identical initial Pb isotope signature (Pb<sub>SMB</sub>). Because Pb is volatile while U is refractory, Pb<sub>SMB</sub> can provide constraints for the timing of volatile depletion, most likely dating the time of Moon formation by a giant impact. The Pb<sub>SMB</sub> is a link between the initial Pb composition of lunar mare basalts and the Moon's early evolution via a two-stage Pb evolution model that provides a simplified but informative framework. Using four mare basalts with well-constrained ages and initial Pb isotopic compositions, we estimate the Moon's formation time at <span><math><msubsup><mn>4516</mn><mrow><mo>−</mo><mn>18</mn></mrow><mrow><mo>+</mo><mn>21</mn></mrow></msubsup></math></span> Ma and the SMB formation time at <span><math><msubsup><mn>4377</mn><mrow><mo>−</mo><mn>27</mn></mrow><mrow><mo>+</mo><mn>57</mn></mrow></msubsup></math></span> Ma, which we regard as the preferred solution within the statistical framework of the model. Our modelling strategy also facilitates the dating of mare basalt fragments lacking Zr-bearing minerals using the initial Pb isotopic compositions constrained by U-poor minerals.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116889"},"PeriodicalIF":3.0,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692533","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}
Pub Date : 2025-11-26DOI: 10.1016/j.icarus.2025.116887
C. Snodgrass , E. Mazzotta Epifani , C. Tubiana , J.P. Sánchez , N. Biver , L. Inno , M.M. Knight , P. Lacerda , J. De Keyser , A. Donaldson , N.J.T. Edberg , M. Galand , A. Guilbert-Lepoutre , P. Henri , S. Kasahara , H. Kawakita , R. Kokotanekova , M. Kueppers , M. Micheli , M. Pajusalu , E. Jehin
Comet Interceptor is an ESA science mission with payload contributions from ESA Member States and with an international participation by JAXA. It is the first mission that is being designed, built, and potentially launched before its target is known. This approach will enable the spacecraft to perform the first mission to a Long Period Comet from the Oort Cloud, as these comets have fleeting visits to the inner Solar System lasting only months to years from first discovery, too short for the usual process of mission development to be followed. In this paper we describe a number of factors that need to be considered in selecting a target for the mission, including scientific, orbital, spacecraft and instrument constraints, and discussion of different prioritisation strategies. We find that, in the case where we have a choice of targets, our decisions will mostly be driven by orbital information, which we will have relatively early on, with information on the activity level of the comet an important but secondary consideration. As cometary activity levels are notoriously hard to predict based on early observations alone, this prioritisation / decision approach based more on orbits gives us confidence that a good comet that is compatible with the spacecraft constraints will be selectable with sufficient warning time to allow the mission to intercept it.
{"title":"Considerations on the process of target selection for the Comet Interceptor mission","authors":"C. Snodgrass , E. Mazzotta Epifani , C. Tubiana , J.P. Sánchez , N. Biver , L. Inno , M.M. Knight , P. Lacerda , J. De Keyser , A. Donaldson , N.J.T. Edberg , M. Galand , A. Guilbert-Lepoutre , P. Henri , S. Kasahara , H. Kawakita , R. Kokotanekova , M. Kueppers , M. Micheli , M. Pajusalu , E. Jehin","doi":"10.1016/j.icarus.2025.116887","DOIUrl":"10.1016/j.icarus.2025.116887","url":null,"abstract":"<div><div>Comet Interceptor is an ESA science mission with payload contributions from ESA Member States and with an international participation by JAXA. It is the first mission that is being designed, built, and potentially launched <em>before</em> its target is known. This approach will enable the spacecraft to perform the first mission to a Long Period Comet from the Oort Cloud, as these comets have fleeting visits to the inner Solar System lasting only months to years from first discovery, too short for the usual process of mission development to be followed. In this paper we describe a number of factors that need to be considered in selecting a target for the mission, including scientific, orbital, spacecraft and instrument constraints, and discussion of different prioritisation strategies. We find that, in the case where we have a choice of targets, our decisions will mostly be driven by orbital information, which we will have relatively early on, with information on the activity level of the comet an important but secondary consideration. As cometary activity levels are notoriously hard to predict based on early observations alone, this prioritisation / decision approach based more on orbits gives us confidence that a good comet that is compatible with the spacecraft constraints will be selectable with sufficient warning time to allow the mission to intercept it.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"447 ","pages":"Article 116887"},"PeriodicalIF":3.0,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692534","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}
We present a novel empirical method for correcting asteroid phase curves for rotational and geometrical effects using precomputed spin-and-shape models. Our approach normalizes sparse photometric data to a pole-on geometry, enabling consistent phase-curve fitting across apparitions. We fit both the and phase functions to the normalized data. We also numerically derive new constraints on parameter ranges that ensure physically meaningful solutions. These constraints are based on the requirement that the reduced magnitude must monotonically decrease with phase angle and remain within plausible slope bounds. Compared to earlier bounds, our new constraints are more permissive. We also compare derivative-based and derivative-free optimization methods, highlighting convergence issues with the function and offering mitigation strategies. We applied our method to over 25,000 asteroids observed by the ATLAS survey, demonstrating its usability. The new method enables the selection of the preferred spin-and-shape solution based on either statistical phase-curve model selection criteria and/or physically motivated constraints on the phase-curve shape.
{"title":"Asteroid phase curve modeling with empirical correction for shape and viewing geometry","authors":"Dagmara Oszkiewicz , Przemysław Bartczak , Milagros Colazo , Antti Penttilä","doi":"10.1016/j.icarus.2025.116886","DOIUrl":"10.1016/j.icarus.2025.116886","url":null,"abstract":"<div><div>We present a novel empirical method for correcting asteroid phase curves for rotational and geometrical effects using precomputed spin-and-shape models. Our approach normalizes sparse photometric data to a pole-on geometry, enabling consistent phase-curve fitting across apparitions. We fit both the <span><math><mrow><mi>H</mi><mo>,</mo><mspace></mspace><msub><mrow><mi>G</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mspace></mspace><msub><mrow><mi>G</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span> and <span><math><mrow><mi>H</mi><mo>,</mo><mspace></mspace><msub><mrow><mi>G</mi></mrow><mrow><mn>12</mn></mrow></msub></mrow></math></span> phase functions to the normalized data. We also numerically derive new constraints on parameter ranges that ensure physically meaningful solutions. These constraints are based on the requirement that the reduced magnitude must monotonically decrease with phase angle and remain within plausible slope bounds. Compared to earlier bounds, our new constraints are more permissive. We also compare derivative-based and derivative-free optimization methods, highlighting convergence issues with the <span><math><mrow><mi>H</mi><mo>,</mo><mspace></mspace><msub><mrow><mi>G</mi></mrow><mrow><mn>12</mn></mrow></msub></mrow></math></span> function and offering mitigation strategies. We applied our method to over 25,000 asteroids observed by the ATLAS survey, demonstrating its usability. The new method enables the selection of the preferred spin-and-shape solution based on either statistical phase-curve model selection criteria and/or physically motivated constraints on the phase-curve shape.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"446 ","pages":"Article 116886"},"PeriodicalIF":3.0,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621250","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}
Pub Date : 2025-11-14DOI: 10.1016/j.icarus.2025.116885
Bangaru Rama Prasadu, Rajib Mia
In this paper, we investigate the motion of an infinitesimal body in the framework of the modified elliptic restricted three-body problem by taking into account additional forces due to albedo, radiation pressure, the oblateness of the primaries’ and the dust belt. We obtain semi-analytical solutions of locations for non-collinear equilibrium points. The positions of non-collinear equilibrium points are shown graphically for different values of perturbation parameters. To investigate the motion of the infinitesimal body, we have chosen three real astronomical systems: the Sun–Mars, Proxima Centauri, and Sun–Saturn. The effects of different perturbation parameters on the position of non-collinear equilibrium points are analysed. The linear stability analysis of equilibrium points is performed by computing the critical mass ratio. Our findings indicate that the stability and instability of non-collinear equilibrium points are influenced by the mass ratio and specific perturbation parameters associated with each system.
{"title":"Influence of albedo, radiation pressure, oblateness, and dust belt on the stability in the generalized elliptic restricted three-body problem","authors":"Bangaru Rama Prasadu, Rajib Mia","doi":"10.1016/j.icarus.2025.116885","DOIUrl":"10.1016/j.icarus.2025.116885","url":null,"abstract":"<div><div>In this paper, we investigate the motion of an infinitesimal body in the framework of the modified elliptic restricted three-body problem by taking into account additional forces due to albedo, radiation pressure, the oblateness of the primaries’ and the dust belt. We obtain semi-analytical solutions of locations for non-collinear equilibrium points. The positions of non-collinear equilibrium points are shown graphically for different values of perturbation parameters. To investigate the motion of the infinitesimal body, we have chosen three real astronomical systems: the Sun–Mars, Proxima Centauri, and Sun–Saturn. The effects of different perturbation parameters on the position of non-collinear equilibrium points are analysed. The linear stability analysis of equilibrium points is performed by computing the critical mass ratio. Our findings indicate that the stability and instability of non-collinear equilibrium points are influenced by the mass ratio and specific perturbation parameters associated with each system.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"446 ","pages":"Article 116885"},"PeriodicalIF":3.0,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577340","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}
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