Icarus最新文献_第7页

The Viking biology experiments on Mars revisited

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-30 DOI: 10.1016/j.icarus.2025.116466

Christopher P. McKay, Richard C. Quinn, Carol R. Stoker

引用次数: 0

Impactor core breakup during impact into a magma ocean: A parameter study

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-30 DOI: 10.1016/j.icarus.2025.116464

Randolph Röhlen , Kai Wünnemann , Laetitia Allibert , Christian Maas , Ulrich Hansen

{"title":"Impactor core breakup during impact into a magma ocean: A parameter study","authors":"Randolph Röhlen , Kai Wünnemann , Laetitia Allibert , Christian Maas , Ulrich Hansen","doi":"10.1016/j.icarus.2025.116464","DOIUrl":"10.1016/j.icarus.2025.116464","url":null,"abstract":"<div><div>The present day concentrations of highly siderophile elements in Earth’s mantle cannot be sufficiently explained by planetary differentiation processes. Material from iron cores of large differentiated bodies, incorporated into a magma ocean due to impact during the late accretion phase, may offer an explanation for the increased abundance of highly siderophile elements, which are considered a measure of the late addition of material. For the chemical equilibration of metallic impactor core material with a silicate magma ocean it is important to know whether the core breaks up. It could shatter into fragments that mix with the magma ocean or penetrates the magma ocean as a coherent mass that does not equilibrate with the surrounding silicates. In order to quantify the fragmentation process between these two end-member cases we performed hydrocode simulations of differentiated impactors into magma oceans at different impactor sizes, impact velocities and magma ocean depths. For this, we developed and implemented a new disruption method into our simulation code, which allows for a more realistic and quantitative description than previously possible. We find that there is significant breakup of the impactor core, increasing with greater magma ocean depth, until the impactor core is completely fragmented at a depth of more than twice the impactor radius. If the magma ocean is shallower, large portions of the impactor core can reach the magma ocean bottom before fragmenting, hence avoiding chemical reequilibration with the surrounding silicates.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"431 ","pages":"Article 116464"},"PeriodicalIF":2.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143193413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhancing lunar DEM data using super-resolution techniques and optimizing the faster R-CNN network for sub-kilometer crater detection

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-28 DOI: 10.1016/j.icarus.2025.116483

ZhiCheng Zhong , Jialong Lai , YaQi Zhong , Yi Xu , Feifei Cui

{"title":"Enhancing lunar DEM data using super-resolution techniques and optimizing the faster R-CNN network for sub-kilometer crater detection","authors":"ZhiCheng Zhong , Jialong Lai , YaQi Zhong , Yi Xu , Feifei Cui","doi":"10.1016/j.icarus.2025.116483","DOIUrl":"10.1016/j.icarus.2025.116483","url":null,"abstract":"<div><div>Meteorite impact craters are the most prominent geomorphological features on the lunar surface, playing a crucial role in studying lunar geological characteristics, evolution, and the selection of landing sites for spacecraft. However, due to the resolution limitations of global lunar Digital Elevation Models (DEM), existing DEM-based automatic crater detection methods struggle to identify small craters effectively. This paper proposes an SR-Net method based on super-resolution techniques to address this challenge to enhance lunar DEM image features. We combine this method with an improved Faster R-CNN algorithm to efficiently detect small craters. We used the Robbins database for training and testing, and we evaluated the model's performance for detecting craters with diameters greater than 1 km. Experimental results showed that the improved model achieved a recall rate of 81.2 %, a precision of 76 %, and an F1 score of 78.5 % on the test set. In the 4× super-resolved DEM images, we detected some small craters, less than 1 km in diameter, in the Change-5 landing area that were not recorded in the Robbins database. After manual inspection by four experts, the average false positive rate(FPR) for small craters that were more prominent than 500 m in diameter was 10 %, while the false positive rate for craters more prominent than 700 m dropped to 5 %. The results demonstrate that the proposed method significantly improves the detection of small craters, particularly in low-resolution scenarios, providing a viable solution for small crater detection tasks.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"430 ","pages":"Article 116483"},"PeriodicalIF":2.5,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148050","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

Low dispersion spectra of lunar impact flashes

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-28 DOI: 10.1016/j.icarus.2025.116480

Masahisa Yanagisawa , Yuki Uchida , Seiya Kurihara , Shinsuke Abe , Ryota Fuse , Satoshi Tanaka , Keisuke Onodera , Taichi Kawamura , Ryuhei Yamada

{"title":"Low dispersion spectra of lunar impact flashes","authors":"Masahisa Yanagisawa , Yuki Uchida , Seiya Kurihara , Shinsuke Abe , Ryota Fuse , Satoshi Tanaka , Keisuke Onodera , Taichi Kawamura , Ryuhei Yamada","doi":"10.1016/j.icarus.2025.116480","DOIUrl":"10.1016/j.icarus.2025.116480","url":null,"abstract":"<div><div>Lunar impact flashes are observed at collisions of meteoroids against the non-sunlit lunar surface. They appear suddenly and usually last only 0.1 s or less in visible light. Using our spectral video cameras, we made observations to obtain their low dispersion spectra from Oct. 2017 to Dec. 13, 2018. We detected five flashes confirmed by multiple site observations and eight unconfirmed flashes. The spectra of the confirmed flashes in the 400–800 nm wavelengths are continuous and red. The best-fitted single blackbody spectra to these spectra show temperatures of 2200–4000 K. The spectrum at the beginning of the brightest confirmed flash may show the optical radiation from the impact-generated vapor plume. The rapid cooling of the impact-generated fine droplets could explain the decrease in brightness and temperature between the subsequent two video frames. The temperature of this flash remained above 2300 K, even 80 ms (milliseconds) after the flash appearance, indicating the existence of coarse incandescent ejecta that cools slowly. This flash's spectral evolution would show the following three processes of meteoroids' impact phenomena on the moon: vapor plume generation, rapid cooling of fine droplets that would be later the lunar spherical glasses, and the ejection of incandescent coarse particles probably melt and solid particle aggregates.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"434 ","pages":"Article 116480"},"PeriodicalIF":2.5,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-precision permittivity estimation of the Lunar and Mars based on an enhanced approach considering GPR antenna positions

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-28 DOI: 10.1016/j.icarus.2025.116485

Shuning Liu , Yan Su , Chunyu Ding , Wei Du , Yuhang Liu

{"title":"High-precision permittivity estimation of the Lunar and Mars based on an enhanced approach considering GPR antenna positions","authors":"Shuning Liu , Yan Su , Chunyu Ding , Wei Du , Yuhang Liu","doi":"10.1016/j.icarus.2025.116485","DOIUrl":"10.1016/j.icarus.2025.116485","url":null,"abstract":"<div><div>The relative permittivity of a material measures its ability to store electric energy in an electric field. It is a significant parameter for characterizing the dielectric polarizability of a material. The hyperbolic fitting method is commonly used to estimate the relative permittivity of materials detected in the ground penetrating radar (GPR) area. Existing hyperbolic fitting methods often ignore the varying positions of transceiver antennas. This paper introduces an improved approach considering GPR antenna positions in three dimensions and it analyses the influencing factors which can result in estimation errors by gprMax simulations. When the buried object is deeper than 4 m, the general estimated error is less than 5 %. Additionally, the proposed method is also employed to both the high-frequency channel data of the Lunar Penetrating Radar (LPR) and Mars Rover Subsurface Penetrating Radar (RoSPR) according to their different transceiver antenna positions to estimate the dielectric constant at the Chang'E-4 (CE-4) and Tianwen-1 landing site, respectively. The calculated permittivity at the CE-4 landing site is <span><math><mn>4.28</mn><mo>±</mo><mn>1.12</mn></math></span> and that at the Tianwen-1 landing site is <span><math><mn>3.52</mn><mo>±</mo><mn>1.09</mn></math></span>. They are both slightly larger than the result obtained by the traditional hyperbolic fitting method. From their obtained dielectric constant maps, although CE-4 obtained a deeper distribution of permittivity, the distribution of dielectric constant at the CE-4 landing site is more homogeneous, indicating a more uniform lunar regolith. It suggests that, compared to the Moon, Mars experiences lower levels of space weathering at these landing sites due to the protection of the Martian atmosphere, which may cause heterogeneity of the shallow subsurface layer at the Tianwen-1 landing site.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"430 ","pages":"Article 116485"},"PeriodicalIF":2.5,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147979","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

Saturn satellite Hyperion: Morphology of its impact craters based on results of NASA mission Cassini

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-27 DOI: 10.1016/j.icarus.2025.116467

A.T. Basilevsky , A.E. Zubarev , I.E. Nadezhdina , B.A. Ivanov , V.A. Dorofeeva , N.A. Kozlova

{"title":"Saturn satellite Hyperion: Morphology of its impact craters based on results of NASA mission Cassini","authors":"A.T. Basilevsky , A.E. Zubarev , I.E. Nadezhdina , B.A. Ivanov , V.A. Dorofeeva , N.A. Kozlova","doi":"10.1016/j.icarus.2025.116467","DOIUrl":"10.1016/j.icarus.2025.116467","url":null,"abstract":"<div><div>Hyperion, a satellite of Saturn, has a shape which can be approximated by the triaxial ellipsoid with axes of 355, 257, and 213 km. Here its surface morphology, geology, composition, and some issues of its origin are described based on images taken by the Cassini Visible and Infrared Mapping Spectrometer and other data obtained during the mission. The surface of this body is densely populated with impact craters with diameters from less than a few kilometers to 20–30 km. High depth/diameter ratios (∼0.3) probably being due to the high porosity of the Hyperion material are characteristic of these craters. Another notable feature of many Hyperion craters is the presence of rectilinear parts of their rims, imparting polygonal shapes to the craters. These shapes are probably due to simultaneous impacts forming neighboring craters and to presence of fractures/faults in the body material. On Hyperion, a large 200 × 250 km crater is present. Its depth is ∼35 km and it has a central peak ∼100 km in diameter and ∼ 5–7 km high above the floor level. Hyperion surface materials are characterized by two major types: the dominant one is visually light and composed mostly of H<sub>2</sub>O ice, while the subordinate one is visually dark and showing spectral signatures of hydrocarbons. Hyperion probably is a captured body arrived from more distant areas of the solar system.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"430 ","pages":"Article 116467"},"PeriodicalIF":2.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148049","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

Mapping of potential mass wasting on Enceladus

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-27 DOI: 10.1016/j.icarus.2025.116471

K. Fred-Velez , S.L. Pérez-Cortés , A.M. Bramson , T.R. Hudgins

引用次数: 0

Geomorphic analysis of lobate debris aprons on Pluto from New Horizons images

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-27 DOI: 10.1016/j.icarus.2025.116468

Caitlin Ahrens , Alissa Earle

引用次数: 0

Astrometric observations of Phoebe from 2010 to 2019 based on Gaia DR3

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-22 DOI: 10.1016/j.icarus.2025.116457

D. Yan , R.C. Qiao , X. Cheng , H.Y. Zhang , Y. Yu

引用次数: 0

Wave transmission through the megaregolith as a mechanism for lunar cold spot formation

IF 2.5 2区物理与天体物理

Icarus Pub Date : 2025-01-22 DOI: 10.1016/j.icarus.2025.116461

Eric S. Frizzell , Christine M. Hartzell , Nicholas C. Schmerr

{"title":"Wave transmission through the megaregolith as a mechanism for lunar cold spot formation","authors":"Eric S. Frizzell , Christine M. Hartzell , Nicholas C. Schmerr","doi":"10.1016/j.icarus.2025.116461","DOIUrl":"10.1016/j.icarus.2025.116461","url":null,"abstract":"<div><div>In this work we consider a lunar cold spot formation mechanism that is enabled by the granular nature of the regolith and an abrupt transition to the layer of boulders just below it (the upper megaregolith). Despite their commonplace occurrence, cold spots (regions of reduced thermal inertia surface regolith surrounding fresh craters) remain an unexplained result of the impact process. Though they represent a minimally disruptive modification of the surface (there is no sign of their existence other than a temperature signature), cold spots are observed at distances of more than 100 crater radii from the impact site. Here we propose that the long runout distances seen in cold spots (the distance over which the surface can be dilated) are enabled by impact energy decaying through meter scale subsurface boulders. Buried energy propagating radially outward would act to drive and maintain a surface dilating wave (proposed in other recent works) that uniformly reduces bulk density near to the impact site and leads to the formation of cold spot rays when large buried boulder layers are particularly well connected. We evaluate this hypothesis via simulated piston impacts into long, randomly packed 3D granular assemblies. We find that runout distance is proportional to particle size, suggesting that the meter scale boulders of the megaregolith may support long range energy propagation over cold spot scale distances. Our results suggest that the proposed cold spot generation mechanism may be a previously overlooked impact-induced gardening processes applicable to regolith covered bodies with a layered near surface structure similar to the Moon.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"429 ","pages":"Article 116461"},"PeriodicalIF":2.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0