Pub Date : 2025-10-30DOI: 10.1016/j.icarus.2025.116868
R. Morales-Juberías , Liming Li , Timothy Dowling , Serenity Mercuri , Amy Simon , Ramanakumar Sankar
We use spacecraft imaging and numerical modeling to analyze the morphology and dynamics of an interaction between a cyclone and an anticyclone in the northern hemisphere of Jupiter. The anticyclone, which is the smaller vortex, rotates around the cyclone such that it is displaced in latitude from one shear zone to the next. This is the first detailed characterization of an interaction of this type, showing an anticyclone crossing a cyclonic region. We also use a three-dimensional numerical model to identify and constrain vortex and environmental parameters that affect this behavior. Our results show that, depending on the initial latitudinal separation between the spots, their relative strength and the background static stability of the atmosphere, three distinct types of interactions that can occur. Namely, they can hop past each other, they can repel each other, or the cyclone can pull the anticyclone down as observed. The best match to the observed interaction and latitude displacement occurs for impact parameters less than and for values of the background static stability between 8 and at the bottom of the model, which would correspond to a high concentration of water in this region of the atmosphere, in which most of the lightning on the planet is detected.
{"title":"Interaction between oppositely signed vortices on adjacent domains in Jupiter","authors":"R. Morales-Juberías , Liming Li , Timothy Dowling , Serenity Mercuri , Amy Simon , Ramanakumar Sankar","doi":"10.1016/j.icarus.2025.116868","DOIUrl":"10.1016/j.icarus.2025.116868","url":null,"abstract":"<div><div>We use spacecraft imaging and numerical modeling to analyze the morphology and dynamics of an interaction between a cyclone and an anticyclone in the northern hemisphere of Jupiter. The anticyclone, which is the smaller vortex, rotates around the cyclone such that it is displaced in latitude from one shear zone to the next. This is the first detailed characterization of an interaction of this type, showing an anticyclone crossing a cyclonic region. We also use a three-dimensional numerical model to identify and constrain vortex and environmental parameters that affect this behavior. Our results show that, depending on the initial latitudinal separation between the spots, their relative strength and the background static stability of the atmosphere, three distinct types of interactions that can occur. Namely, they can hop past each other, they can repel each other, or the cyclone can pull the anticyclone down as observed. The best match to the observed interaction and latitude displacement occurs for impact parameters less than <span><math><mrow><mo>≈</mo><mn>3</mn><msub><mrow><mi>L</mi></mrow><mrow><mi>d</mi></mrow></msub></mrow></math></span> and for values of the background static stability <span><math><mi>N</mi></math></span> between 8 and <span><math><mrow><mn>10</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> at the bottom of the model, which would correspond to a high concentration of water in this region of the atmosphere, in which most of the lightning on the planet is detected.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116868"},"PeriodicalIF":3.0,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462554","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 : 2025-10-28DOI: 10.1016/j.icarus.2025.116867
Z.Y. Wang , H.Y. Zhang , R.C. Qiao , Y. Yu , D. Yan , K. Tang
With the rapid development of deep-space exploration within the Solar System, the demand for precise ephemerides of planets and their natural satellites is growing steadily. Continuous updating of these ephemerides relies on long-term observational data, and ground-based observations play a vital role in improving ephemeris accuracy. However, the bright halos surrounding planets can reduce both the detection rate and the positional accuracy of their nearby satellites. To address this issue, we conducted a comparative study of two image-enhancement methods using 1030 CCD images of Uranus and its neighboring satellites obtained at Yunnan Observatory from 13 to 18 November 2020. The results demonstrate that a regularized Retinex algorithm effectively removes the halo and significantly improves the detection rate and positional accuracy of Uranian satellites. Stellar positions in this study are taken from Gaia DR3, Uranus positions from DE441, and the positions of Uranian satellites from Lainey et al. (2015).
随着太阳系内深空探测的迅速发展，对行星及其天然卫星精确星历表的需求正在稳步增长。这些星历表的持续更新依赖于长期的观测数据，而地面观测对提高星历表的精度起着至关重要的作用。然而，行星周围明亮的光晕会降低附近卫星的探测率和定位精度。为了解决这一问题，我们利用云南天文台于2020年11月13日至18日获得的1030张天王星及其邻近卫星的CCD图像，对两种图像增强方法进行了比较研究。结果表明，正则化Retinex算法有效地消除了天王星卫星的光晕，显著提高了天王星卫星的检测率和定位精度。本研究中的恒星位置取自盖亚DR3，天王星位置取自DE441，天王星卫星位置取自Lainey et al.（2015）。
{"title":"A new method to improve the detection rate and astrometric accuracy of natural satellites located in the halo of Uranus","authors":"Z.Y. Wang , H.Y. Zhang , R.C. Qiao , Y. Yu , D. Yan , K. Tang","doi":"10.1016/j.icarus.2025.116867","DOIUrl":"10.1016/j.icarus.2025.116867","url":null,"abstract":"<div><div>With the rapid development of deep-space exploration within the Solar System, the demand for precise ephemerides of planets and their natural satellites is growing steadily. Continuous updating of these ephemerides relies on long-term observational data, and ground-based observations play a vital role in improving ephemeris accuracy. However, the bright halos surrounding planets can reduce both the detection rate and the positional accuracy of their nearby satellites. To address this issue, we conducted a comparative study of two image-enhancement methods using 1030 CCD images of Uranus and its neighboring satellites obtained at Yunnan Observatory from 13 to 18 November 2020. The results demonstrate that a regularized Retinex algorithm effectively removes the halo and significantly improves the detection rate and positional accuracy of Uranian satellites. Stellar positions in this study are taken from Gaia DR3, Uranus positions from DE441, and the positions of Uranian satellites from Lainey et al. (2015).</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116867"},"PeriodicalIF":3.0,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462556","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 : 2025-10-24DOI: 10.1016/j.icarus.2025.116858
A.K. Dhaikar, R.S. Pandey
This research explores kinetic approach for electrostatic ion-cyclotron instabilities related to higher harmonic modes () in Jupiter's magnetosphere at radial distances of 10 and 15 Jupiter radii (RJ). We include the effects of Bessel functions of orders 1 and 2 for the fundamental (n = 1) and first higher harmonic (n = 2) modes. With a kinetic treatment and the method of characteristics solution, we obtain an altered dispersion relation that includes finite Larmor radius effects and latitude-variable magnetic field, described as . We analyze the effects of various plasma parameters such as electric field inhomogeneity, velocity shear scale length, temperature anisotropy, magnitude of electric field, electron-to-ion temperature ratio, density gradient, and propagation angle on the dimensionless growth rate of these instabilities as a function of . Numerical calculations, corroborated by the Galileo and Juno mission data, demonstrate disparate behaviors between the basic (n = 1) and higher harmonic (n = 2) modes. Higher growth rates are found for the fundamental modes, while the higher harmonics are more sensitive to smaller-scale structures. These results highlight the significance of kinetic effects in plasma transport, wave excitation, and auroral activity in Jupiter's fast-rotating, corotation-dominated magnetosphere.
{"title":"Electrostatic ion-cyclotron higher harmonic instability with latitudinal variation of magnetic field & inhomogeneous electric field in Jupiter’s magnetosphere","authors":"A.K. Dhaikar, R.S. Pandey","doi":"10.1016/j.icarus.2025.116858","DOIUrl":"10.1016/j.icarus.2025.116858","url":null,"abstract":"<div><div>This research explores kinetic approach for electrostatic ion-cyclotron instabilities related to higher harmonic modes (<span><math><mi>n</mi><mo>≥</mo><mn>1</mn></math></span>) in Jupiter's magnetosphere at radial distances of 10 and 15 Jupiter radii (R<sub>J</sub>). We include the effects of Bessel functions of orders 1 and 2 for the fundamental (<em>n</em> = 1) and first higher harmonic (<em>n</em> = 2) modes. With a kinetic treatment and the method of characteristics solution, we obtain an altered dispersion relation that includes finite Larmor radius effects and latitude-variable magnetic field, described as <span><math><mi>B</mi><mo>=</mo><msub><mi>B</mi><mn>0</mn></msub><msqrt><mrow><mn>1</mn><mo>+</mo><mn>3</mn><msup><mi>sin</mi><mn>2</mn></msup><msub><mi>θ</mi><mi>mag</mi></msub></mrow></msqrt><mo>/</mo><msup><mi>cos</mi><mn>6</mn></msup><msub><mi>θ</mi><mi>mag</mi></msub></math></span>. We analyze the effects of various plasma parameters such as electric field inhomogeneity, velocity shear scale length, temperature anisotropy, magnitude of electric field, electron-to-ion temperature ratio, density gradient, and propagation angle on the dimensionless growth rate of these instabilities as a function of <span><math><msub><mi>k</mi><mo>⊥</mo></msub><msub><mi>ρ</mi><mi>i</mi></msub></math></span>. Numerical calculations, corroborated by the Galileo and Juno mission data, demonstrate disparate behaviors between the basic (<em>n</em> = 1) and higher harmonic (<em>n</em> = 2) modes. Higher growth rates are found for the fundamental modes, while the higher harmonics are more sensitive to smaller-scale structures. These results highlight the significance of kinetic effects in plasma transport, wave excitation, and auroral activity in Jupiter's fast-rotating, corotation-dominated magnetosphere.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116858"},"PeriodicalIF":3.0,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462682","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 : 2025-10-24DOI: 10.1016/j.icarus.2025.116864
E. Larsen , A. Sánchez-Lavega , T. del Río-Gaztelurrutia , J. Hernández-Bernal
We report new cases of extremely long and narrow clouds, visually similar in their morphology to the Arsia Mons elongated cloud (AMEC) (Hernández-Bernal et al., 2021a, 2022), that form at mid-temperate and subpolar latitudes in both hemispheres of the planet. We focus on four regions with different topography: the rugged mountain range of Thaumasia Highlands (267°E, 40°S), the volcanic region of Alba Patera (250°E, 40°N), the fretted and cratered highland terrain Tempe Terra (285°E, 48°N), and Lyot crater (29.3°E, 50.4°N). We use the images obtained by the Visual Monitoring Camera (VMC) on board the Mars Express mission, profiting from Mars Express' advantageous polar elliptical orbit, which allows us to characterize these clouds at different local times and spatial resolutions. At the elevated region of Thaumasia Highlands clouds form throughout the southern fall and winter during Ls = 0° – 170°, with lengths of up to 2700 km, widths of up to 220 km and heights 10–22 km above the surface. The elongated clouds at Alba Patera and Tempe Terra form during the northern fall and winter seasons between Ls = 180° – 330° with maximum lengths of 2600 km and 1900 km, maximum widths of 270 km and 240 km and heights between 10 and 27 km and 8–22 km respectively. Similarly, the elongated clouds at Lyot crater form during Ls = 180° – 340° and can have lengths of up to 2600 km and widths of up to 300 km. However, their heights are lower ranging 5–16 km over the surface.
{"title":"Orographic elongated clouds in mid-temperate and subpolar latitudes of Mars. I-Observations","authors":"E. Larsen , A. Sánchez-Lavega , T. del Río-Gaztelurrutia , J. Hernández-Bernal","doi":"10.1016/j.icarus.2025.116864","DOIUrl":"10.1016/j.icarus.2025.116864","url":null,"abstract":"<div><div>We report new cases of extremely long and narrow clouds, visually similar in their morphology to the Arsia Mons elongated cloud (AMEC) (Hernández-Bernal et al., 2021a, 2022), that form at mid-temperate and subpolar latitudes in both hemispheres of the planet. We focus on four regions with different topography: the rugged mountain range of Thaumasia Highlands (267°E, 40°S), the volcanic region of Alba Patera (250°E, 40°N), the fretted and cratered highland terrain Tempe Terra (285°E, 48°N), and Lyot crater (29.3°E, 50.4°N). We use the images obtained by the Visual Monitoring Camera (VMC) on board the Mars Express mission, profiting from Mars Express' advantageous polar elliptical orbit, which allows us to characterize these clouds at different local times and spatial resolutions. At the elevated region of Thaumasia Highlands clouds form throughout the southern fall and winter during Ls = 0° – 170°, with lengths of up to 2700 km, widths of up to 220 km and heights 10–22 km above the surface. The elongated clouds at Alba Patera and Tempe Terra form during the northern fall and winter seasons between Ls = 180° – 330° with maximum lengths of 2600 km and 1900 km, maximum widths of 270 km and 240 km and heights between 10 and 27 km and 8–22 km respectively. Similarly, the elongated clouds at Lyot crater form during Ls = 180° – 340° and can have lengths of up to 2600 km and widths of up to 300 km. However, their heights are lower ranging 5–16 km over the surface.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116864"},"PeriodicalIF":3.0,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417805","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 : 2025-10-22DOI: 10.1016/j.icarus.2025.116862
Andrew Marshall-Lee , Apostolos Christou , Marco Delbo , Alice Humpage , Rogerio Deienno , Kevin Walsh
The Hierarchical Clustering Method (HCM) is the de-facto clustering algorithm in the search for groups of “family” asteroids that were formed due to the breakup of a larger parent body. In this work, we feed to the HCM a number of synthetic asteroid families at different positions in the main belt and of different dynamical ages. We then measure how effectively the algorithm can recover the family members, while minimising the inclusion of non-family members. The three metrics of “accuracy”, “precision”, and “recall” were used to characterise the HCM efficiency. The most important factor in the HCM’s ability to cluster families was found to be the relative number density between the family and the asteroid background it is situated in. We compared families to the background in a parameter space defined by proper orbital elements semi-major axis, eccentricity, and inclination (a, e, i), and for families approximately four times denser than the background 50% of the original family is recovered independently of age. However, to reach these relative densities for families older than 2 Gyr it was necessary to artificially reduce the synthetic background population. We conclude that older families would be all but undetectable in the real main belt, using the HCM.
{"title":"Characterising the efficiency of the hierarchical clustering method","authors":"Andrew Marshall-Lee , Apostolos Christou , Marco Delbo , Alice Humpage , Rogerio Deienno , Kevin Walsh","doi":"10.1016/j.icarus.2025.116862","DOIUrl":"10.1016/j.icarus.2025.116862","url":null,"abstract":"<div><div>The Hierarchical Clustering Method (HCM) is the de-facto clustering algorithm in the search for groups of “family” asteroids that were formed due to the breakup of a larger parent body. In this work, we feed to the HCM a number of synthetic asteroid families at different positions in the main belt and of different dynamical ages. We then measure how effectively the algorithm can recover the family members, while minimising the inclusion of non-family members. The three metrics of “accuracy”, “precision”, and “recall” were used to characterise the HCM efficiency. The most important factor in the HCM’s ability to cluster families was found to be the relative number density between the family and the asteroid background it is situated in. We compared families to the background in a parameter space defined by proper orbital elements semi-major axis, eccentricity, and inclination (a, e, i), and for families approximately four times denser than the background <span><math><mo>∼</mo></math></span> 50% of the original family is recovered independently of age. However, to reach these relative densities for families older than 2 Gyr it was necessary to artificially reduce the synthetic background population. We conclude that older families would be all but undetectable in the real main belt, using the HCM.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116862"},"PeriodicalIF":3.0,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417803","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 : 2025-10-22DOI: 10.1016/j.icarus.2025.116863
Shuai Shao, Meng Xiao, Zhizhong Kang, Teng Hu, Zhen Cao, Yingnan Zhang, Jinhao Cai, ZhongLu Lei, Haoxiang Hu
Impact craters represent the most ubiquitous geomorphological feature on the lunar surface. Classifying these craters according to their degradation grades facilitates the analysis of the impact history and evolutionary processes within a given region. Traditional classification methods predominantly rely on manual interpretation, which is inherently limited in scalability for large-scale automation. To address this challenge, we propose a dual-branch automatic classification network for lunar simple crater degradation grades, named LSCDNet, which integrates both image data and morphological parameters. The network leverages DenseNet for feature extraction and employs a Transformer encoder to model the intricate relationships among the morphological parameters of the craters. Dynamic weighting fusion is applied to effectively combine these two feature types. During the training process, the MultiMarginLoss function is utilized to increase class score margins, thereby enhancing the overall classification performance. To evaluate the effectiveness of the proposed method, we construct the Lunar Simple Crater Degradation Grades (LSCD) dataset. Experimental results demonstrate that the proposed method achieves a classification accuracy of 83.12%, precision of 83.00%, recall of 82.36%, and an F1 score of 82.64% on the validation set, indicating strong performance. Moreover, through SHAP-based interpretability analysis, we identify the specific contributions of crater image features and morphological parameters in the model’s decision-making process. Notably, slope of the crater’s outer wall and depth-to-diameter ratio emerge as key factors in distinguishing among different degradation grades. Further analysis reveals that as the degradation grade of craters increases, the morphological parameters exhibit consistent trends, thereby offering deeper insights into the evolutionary process after crater formation. Finally, LSCDNet was applied to different geological unit areas to analyze the distribution of impact crater degradation degrades with variations in geological age, demonstrating that the degradation degree of impact craters has potential dating value.
{"title":"A dual-branch automatic classification network for lunar simple crater degradation grades integrating image and morphological parameters","authors":"Shuai Shao, Meng Xiao, Zhizhong Kang, Teng Hu, Zhen Cao, Yingnan Zhang, Jinhao Cai, ZhongLu Lei, Haoxiang Hu","doi":"10.1016/j.icarus.2025.116863","DOIUrl":"10.1016/j.icarus.2025.116863","url":null,"abstract":"<div><div>Impact craters represent the most ubiquitous geomorphological feature on the lunar surface. Classifying these craters according to their degradation grades facilitates the analysis of the impact history and evolutionary processes within a given region. Traditional classification methods predominantly rely on manual interpretation, which is inherently limited in scalability for large-scale automation. To address this challenge, we propose a dual-branch automatic classification network for lunar simple crater degradation grades, named LSCDNet, which integrates both image data and morphological parameters. The network leverages DenseNet for feature extraction and employs a Transformer encoder to model the intricate relationships among the morphological parameters of the craters. Dynamic weighting fusion is applied to effectively combine these two feature types. During the training process, the MultiMarginLoss function is utilized to increase class score margins, thereby enhancing the overall classification performance. To evaluate the effectiveness of the proposed method, we construct the Lunar Simple Crater Degradation Grades (LSCD) dataset. Experimental results demonstrate that the proposed method achieves a classification accuracy of 83.12%, precision of 83.00%, recall of 82.36%, and an F1 score of 82.64% on the validation set, indicating strong performance. Moreover, through SHAP-based interpretability analysis, we identify the specific contributions of crater image features and morphological parameters in the model’s decision-making process. Notably, slope of the crater’s outer wall and depth-to-diameter ratio emerge as key factors in distinguishing among different degradation grades. Further analysis reveals that as the degradation grade of craters increases, the morphological parameters exhibit consistent trends, thereby offering deeper insights into the evolutionary process after crater formation. Finally, LSCDNet was applied to different geological unit areas to analyze the distribution of impact crater degradation degrades with variations in geological age, demonstrating that the degradation degree of impact craters has potential dating value.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116863"},"PeriodicalIF":3.0,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417807","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}
He pressure-broadening coefficients of CO2 lines were predicted over a wide temperature range (100−3000 K) using requantized classical molecular dynamics simulations (rCMDS). This approach, based on the use of an ab initio intermolecular interaction potential, Newtonian equations of motion, and a requantized procedure, enables the calculation of the spectral density of He-broadened CO2 spectra. The resulting spectra were fitted with the usual Voigt profile to deduce He-broadening coefficients. Requantization was calibrated to match the rCMDS-predicted broadenings coefficients to quantum scattering results at room temperature, available for thirteen lines, computed with the same potential. Comparisons between rCMDS and quantum calculations at 123 K and 760 K showed very good agreements. Excellent agreements with experimental data were also observed at 123 K, 160 K, 565 K, and 760 K. rCMDS calculations were then extended to several temperatures up to 3000 K, enabling prediction of broadening coefficients for rotational quantum numbers up to J = 240, where no prior theoretical or experimental data exist. The temperature dependence of the broadening coefficients was then modeled using either a double power-law model when applicable or the usual single power law. The resulting dataset provides He-broadening coefficients of CO2 lines for J up to 166 for any temperature between 100 K and 3000 K. These results represent the most comprehensive set of line-shape parameters for CO2 perturbed by He, providing improved input for spectroscopic databases and for opacity modeling in planetary and exoplanetary atmospheres.
{"title":"A complete list of He-pressure-broadening coefficient of CO2 lines from 100 K to 3000 K for planet and exoplanet opacity calculations","authors":"Faten Hendaoui , Jean-Michel Hartmann , Hassen Aroui , Ha Tran","doi":"10.1016/j.icarus.2025.116861","DOIUrl":"10.1016/j.icarus.2025.116861","url":null,"abstract":"<div><div>He pressure-broadening coefficients of CO<sub>2</sub> lines were predicted over a wide temperature range (100−3000 K) using requantized classical molecular dynamics simulations (rCMDS). This approach, based on the use of an ab initio intermolecular interaction potential, Newtonian equations of motion, and a requantized procedure, enables the calculation of the spectral density of He-broadened CO<sub>2</sub> spectra. The resulting spectra were fitted with the usual Voigt profile to deduce He-broadening coefficients. Requantization was calibrated to match the rCMDS-predicted broadenings coefficients to quantum scattering results at room temperature, available for thirteen lines, computed with the same potential. Comparisons between rCMDS and quantum calculations at 123 K and 760 K showed very good agreements. Excellent agreements with experimental data were also observed at 123 K, 160 K, 565 K, and 760 K. rCMDS calculations were then extended to several temperatures up to 3000 K, enabling prediction of broadening coefficients for rotational quantum numbers up to <em>J</em> = 240, where no prior theoretical or experimental data exist. The temperature dependence of the broadening coefficients was then modeled using either a double power-law model when applicable or the usual single power law. The resulting dataset provides He-broadening coefficients of CO<sub>2</sub> lines for <em>J</em> up to 166 for any temperature between 100 K and 3000 K. These results represent the most comprehensive set of line-shape parameters for CO<sub>2</sub> perturbed by He, providing improved input for spectroscopic databases and for opacity modeling in planetary and exoplanetary atmospheres.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116861"},"PeriodicalIF":3.0,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417806","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 : 2025-10-20DOI: 10.1016/j.icarus.2025.116859
Elian Ochem, Yves Marrocchi
The dynamic evolution of the solar protoplanetary disk led to the formation of the first solar system solids by condensation, among which amoeboid olivine aggregates (AOAs) are the most abundant. The conditions under which AOAs formed remain poorly constrained, with both equilibrium condensation under sub-solar dust/gas ratios and out-of-equilibrium condensation having been proposed. The recent identification of metal–olivine inclusions (MOIs) in carbonaceous chondrites (CCs) provides a unique opportunity to investigate the conditions of forsterite condensation. Our petrographic survey confirms the frequent occurrence of MOIs in CCs. Their occasional association with AOAs, together with the high MnO/FeO ratios and the 16O-rich composition of forsteritic rims, indicates formation by gas–solid condensation early in the disk's history. These forsteritic rims are chemically depleted in refractory elements such as Ca, Al, and Ti. Combined with existing literature data, our findings support the condensation of both AOAs and MOIs under out-of-equilibrium conditions during transient, localized heating events in a thermally heterogeneous and dynamically evolving disk. A comparison with relict olivine grains in type I chondrules suggests that AOA-MOI association represent plausible type I chondrule precursors. These results question models proposing that Ca–Al–Ti-rich refractory forsterite necessarily predates chondrule formation. Instead, we suggest that Ca–Al–Ti-poor olivine may better preserve information about the nature and conditions of early chondrule precursors.
太阳原行星盘的动态演化导致了第一批太阳系固体的凝结形成，其中以变形虫橄榄石聚集体（AOAs）最为丰富。AOAs形成的条件仍然没有得到很好的约束，在亚太阳尘埃/气体比下的平衡冷凝和非平衡冷凝都被提出。最近在碳质球粒陨石（CCs）中发现的金属橄榄石包裹体（MOIs）为研究橄榄石凝结条件提供了一个独特的机会。我们的岩石学调查证实了在cc中moi的频繁发生。它们偶尔与AOAs结合，再加上高MnO/FeO比率和富16o的锻造体边缘组成，表明在盘的早期历史中是由气固冷凝形成的。这些磨砂体轮辋在化学上缺乏耐火元素，如Ca， Al和Ti。结合现有文献数据，我们的研究结果支持在非平衡条件下，在热非均质和动态演化的圆盘中，局部加热事件发生时，AOAs和moi的凝结。与I型球粒中残余橄榄石颗粒的比较表明，AOA-MOI结合可能是I型球粒的前体。这些结果质疑了认为富钙铝钛难熔橄榄石必然早于球粒形成的模型。相反，我们认为ca - al - ti贫橄榄石可能更好地保存有关早期球粒前体的性质和条件的信息。
{"title":"Formation conditions and chemical composition of early-condensed olivine in the solar protoplanetary disk","authors":"Elian Ochem, Yves Marrocchi","doi":"10.1016/j.icarus.2025.116859","DOIUrl":"10.1016/j.icarus.2025.116859","url":null,"abstract":"<div><div>The dynamic evolution of the solar protoplanetary disk led to the formation of the first solar system solids by condensation, among which amoeboid olivine aggregates (AOAs) are the most abundant. The conditions under which AOAs formed remain poorly constrained, with both equilibrium condensation under sub-solar dust/gas ratios and out-of-equilibrium condensation having been proposed. The recent identification of metal–olivine inclusions (MOIs) in carbonaceous chondrites (CCs) provides a unique opportunity to investigate the conditions of forsterite condensation. Our petrographic survey confirms the frequent occurrence of MOIs in CCs. Their occasional association with AOAs, together with the high MnO/FeO ratios and the <sup>16</sup>O-rich composition of forsteritic rims, indicates formation by gas–solid condensation early in the disk's history. These forsteritic rims are chemically depleted in refractory elements such as Ca, Al, and Ti. Combined with existing literature data, our findings support the condensation of both AOAs and MOIs under out-of-equilibrium conditions during transient, localized heating events in a thermally heterogeneous and dynamically evolving disk. A comparison with relict olivine grains in type I chondrules suggests that AOA-MOI association represent plausible type I chondrule precursors. These results question models proposing that Ca–Al–Ti-rich refractory forsterite necessarily predates chondrule formation. Instead, we suggest that Ca–Al–Ti-poor olivine may better preserve information about the nature and conditions of early chondrule precursors.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116859"},"PeriodicalIF":3.0,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358790","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}
Internal variability of cloud-top super-rotation with periods of about a Venus day is found in a Venus AORI (Atmosphere and Ocean Research Institute, The University of Tokyo) GCM (General Circulation Model), along with diurnal variations of the meridional circulation and long-wave radiative cooling. In the diurnal cycle of the cloud-top zonal flow, the high-latitude jets increase, while the meridional circulation enhances the poleward momentum flux. Subsequently, the equatorial super-rotation becomes its maximum after the high-latitude jets reach their maximum. The present study reveals the formation of the diurnal cycle of the zonal flow by the meridional circulation and the destruction of the diurnal cycle by the amplified Eliassen-Palm (EP) flux in the model. Although the variability of the meridional circulation is stably diurnal throughout the simulation, the periodicity of the EP flux is not always diurnal. The diurnal cycle of the zonal flow becomes weak and the periodicities of ∼two Venus days appear in the model, when the zonal-flow acceleration by the EP flux is stronger than that by the meridional circulation at the equator and at the high-latitude jet cores. Moreover, when cyclic data gaps of cloud-tracking observation are considered in this study, the diurnal cycle of the zonal flow is unclear, and the peak-to-peak intervals of the zonal-wind maxima appear to be ∼two Venus days.
{"title":"Zonal-flow variability associated with meridional circulation at the cloud top in a Venus atmospheric general circulation model","authors":"Masaru Yamamoto , Kohei Ikeda , Masaaki Takahashi , Masaki Satoh","doi":"10.1016/j.icarus.2025.116860","DOIUrl":"10.1016/j.icarus.2025.116860","url":null,"abstract":"<div><div>Internal variability of cloud-top super-rotation with periods of about a Venus day is found in a Venus AORI (Atmosphere and Ocean Research Institute, The University of Tokyo) GCM (General Circulation Model), along with diurnal variations of the meridional circulation and long-wave radiative cooling. In the diurnal cycle of the cloud-top zonal flow, the high-latitude jets increase, while the meridional circulation enhances the poleward momentum flux. Subsequently, the equatorial super-rotation becomes its maximum after the high-latitude jets reach their maximum. The present study reveals the formation of the diurnal cycle of the zonal flow by the meridional circulation and the destruction of the diurnal cycle by the amplified Eliassen-Palm (EP) flux in the model. Although the variability of the meridional circulation is stably diurnal throughout the simulation, the periodicity of the EP flux is not always diurnal. The diurnal cycle of the zonal flow becomes weak and the periodicities of ∼two Venus days appear in the model, when the zonal-flow acceleration by the EP flux is stronger than that by the meridional circulation at the equator and at the high-latitude jet cores. Moreover, when cyclic data gaps of cloud-tracking observation are considered in this study, the diurnal cycle of the zonal flow is unclear, and the peak-to-peak intervals of the zonal-wind maxima appear to be ∼two Venus days.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116860"},"PeriodicalIF":3.0,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417800","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 : 2025-10-19DOI: 10.1016/j.icarus.2025.116857
A.G. Nair , I.B. Smith
The north polar layered deposits of Mars are composed mainly of water ice with varying fractions of dust in the layers. This almost 2-km stack records a history of accumulation and ablation that tells of climatic episodes. The layers are frequently exposed as outcrops at spiral troughs that can be inspected for geomorphological details related to deposition and ablation cycles. Here, we identify and catalog the 226 morphologic features we call “scalloped cliffs” that exhibit tell-tale signs of variable resistance to erosion in sequential layers. The spatial distribution of scalloped cliffs suggests that they are primarily near the margins on the NPLD, especially in the Gemini Scopuli region of Planum Boreum. Many are immediately associated with an unconformity, providing clues to their origin. Additionally, we present two distinct hypotheses behind their formation that relate to alternating layer properties, especially related to dust content and susceptibility to ablation. For each example, we hypothesize that the scalloped cliffs form when friable dust-rich lag deposits, at unconformities, are emplaced between more resistant icy layers and that their unique wavy appearance is due to oblique wind scouring.
{"title":"Scalloped cliff formations of north polar layered deposits of mars: A new catalog","authors":"A.G. Nair , I.B. Smith","doi":"10.1016/j.icarus.2025.116857","DOIUrl":"10.1016/j.icarus.2025.116857","url":null,"abstract":"<div><div>The north polar layered deposits of Mars are composed mainly of water ice with varying fractions of dust in the layers. This almost 2-km stack records a history of accumulation and ablation that tells of climatic episodes. The layers are frequently exposed as outcrops at spiral troughs that can be inspected for geomorphological details related to deposition and ablation cycles. Here, we identify and catalog the 226 morphologic features we call “scalloped cliffs” that exhibit tell-tale signs of variable resistance to erosion in sequential layers. The spatial distribution of scalloped cliffs suggests that they are primarily near the margins on the NPLD, especially in the Gemini Scopuli region of Planum Boreum. Many are immediately associated with an unconformity, providing clues to their origin. Additionally, we present two distinct hypotheses behind their formation that relate to alternating layer properties, especially related to dust content and susceptibility to ablation. For each example, we hypothesize that the scalloped cliffs form when friable dust-rich lag deposits, at unconformities, are emplaced between more resistant icy layers and that their unique wavy appearance is due to oblique wind scouring.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116857"},"PeriodicalIF":3.0,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417801","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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