Icarus最新文献

{"title":"Mars as one system: Insights from the 8th international conference on Mars polar science and exploration","authors":"Isaac.B. Smith ,&nbsp;Chimira Andres ,&nbsp;Shannon Hibbard ,&nbsp;Stefano Nerozzi ,&nbsp;Roberto Aguilar ,&nbsp;Peter Buhler ,&nbsp;Ben Cornford ,&nbsp;Leslie Tamppari ,&nbsp;Timothy N. Titus","doi":"10.1016/j.icarus.2026.116998","DOIUrl":"10.1016/j.icarus.2026.116998","url":null,"abstract":"<div><div>The 8th International Conference on Mars Polar Science and Exploration (ICMPSE) provided new insights into the complex interplay between Martian ice, climate, and atmospheric dynamics. The conference emphasized a holistic view of Mars as a system, where surface processes, subsurface ice, atmospheric dynamics, and historical climate shifts are interconnected. Research updates spanned cutting-edge remote sensing techniques and observations, terrestrial analog studies, and theoretical modeling, providing a multidimensional view of Mars' dynamic history and present-day activity. Numerous presentations highlighted the importance of understanding Mars as an integrated and dynamic system where surface and atmospheric processes interact over various timescales. This paper synthesizes unresolved questions and the major themes discussed, including mid-latitude glaciation, the evolution of the polar layered deposits (PLDs), terrestrial analog studies, climate modeling, and future mission planning. The findings contributed to refining models of Martian climate history, assessing the potential for extant life, and planning future human exploration. We also discuss the historical perspective of Mars Polar Science and new findings since the 7th conference in this series and anticipate the next four to 20 years of science on Mars related to ice, climate, and the atmosphere.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 116998"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the effects of meteoroid impacts on properties of the Hermean exosphere","authors":"A.A. Berezhnoy ,&nbsp;V.V. Shuvalov ,&nbsp;G.V. Belov ,&nbsp;A.E. Ivanova","doi":"10.1016/j.icarus.2026.117013","DOIUrl":"10.1016/j.icarus.2026.117013","url":null,"abstract":"<div><div>The results of numerical modeling of vertical impacts of millimeter-sized spherical meteoroids against a solid surface in vacuum are presented. The impact velocity was varied from 20 to 110 km/s, and both the target and the impactor were assumed to consist of dunite or quartz. The expanding vapor cloud was divided into 15–20 fragments, and for each fragment the time dependences of temperature and pressure and characteristic times of expansion were obtained. Quenched chemical composition of different fragments of impact-produced cloud was estimated for considered range of impact velocities. Theoretical zenith surface column densities of impact-produced and photolysis-generated Mg, Ca, Fe, and Mn atoms near perihelion agree with its observed values within a factor of 2 suggesting that continuous meteoroid bombardment is an important source of these atoms in the Hermean exosphere. High observed temperature of Ca atoms in the Hermean exosphere is explained by preferable formation of Ca atoms in outer regions of clouds formed by 110 km/s impacts and having high expansion velocity comparable to the escape velocity from Mercury.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117013"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Orbital stability of closely-spaced four-planet systems","authors":"Bennet Outland ,&nbsp;Gretchen Noble ,&nbsp;Andrew W. Smith ,&nbsp;Jack J. Lissauer","doi":"10.1016/j.icarus.2026.117025","DOIUrl":"10.1016/j.icarus.2026.117025","url":null,"abstract":"<div><div>We investigate the orbital dynamics of four-planet systems consisting of Earth-mass planets on initially-circular, coplanar orbits around a star of one solar mass. In our simulations, the innermost planet’s semimajor axis is set at 1 AU, with subsequent semimajor axes spaced equally in terms of planets’ mutual Hill radii. Several sets of initial planetary longitudes are investigated, with integrations continuing for up to <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>10</mn></mrow></msup></mrow></math></span> orbits of the innermost planet, stopping if a pair of planets pass within 0.01 AU of each other or if a planet is ejected from the system. We find that the simulated lifetimes of four-planet systems follow the general trend of increasing exponentially with planetary spacing, as seen by previous studies of closely-spaced planets. Four-planet system lifetimes are intermediate between those of three- and five-planet systems and more similar to the latter. Moreover, as with five-planet systems, but in marked contrast to the three-planet case, no initial semimajor axes spacings are found to yield systems that survive several orders of magnitude longer than other similar spacings. First- and second-order mean-motion resonances (MMRs) between planets correlate with reductions in system lifetimes. Additionally, we find that third-order MMRs between planets on neighboring orbits also have a substantial, though smaller, destabilizing effect on systems very near resonance that otherwise would be very long-lived. Local extrema of system lifetimes as a function of planetary spacing occur at slightly smaller initial orbital separation for systems with planets initially at conjunction relative to those in which the planets begin on widely-separated longitudes. This shift is produced by the asymmetric mutual planetary perturbations as the planets separate in longitude from the initial aligned configuration that cause orbits to spread out in semimajor axis.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117025"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New surface composition and temperature maps of Pluto from New Horizons LEISA data","authors":"Alexey Drozdov,&nbsp;Nikolay Emelyanov","doi":"10.1016/j.icarus.2026.117031","DOIUrl":"10.1016/j.icarus.2026.117031","url":null,"abstract":"<div><div>New Horizons RALPH/LEISA near-infrared spectra allow for regional mapping of Pluto’s surface ices and their physical state; however, scan-to-scan artifacts and variable spatial resolution complicate quantitative interpretation. We extend previous LEISA compositional studies (Protopapa et al., 2017; Schmitt et al., 2017; Emran et al., 2023) by combining five close-approach observations into co-registered equirectangular maps at 7 km/pixel and by jointly retrieving surface temperature, ice abundances, and grain sizes using a Hapke-based mixing model.</div><div>We mitigate bad pixels and edge overexposure linked to flat-field uncertainties and correct for residual scan-to-scan spectral discrepancies using per-observation scale and offset terms. The resulting maps provide distributions of CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>-rich ice, N<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-rich ice, H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O ice, and Titan Tholin, alongside a corresponding temperature map.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117031"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drying induces Mars intermediate-sized cracks: New evidence and insight from geometrical quantification","authors":"Jin-Jian Xu ,&nbsp;Hao Zhang ,&nbsp;Chao-Sheng Tang ,&nbsp;Yaowen Yang ,&nbsp;Mohamed Ramy El-Maarry ,&nbsp;Lin Li ,&nbsp;Bin Shi","doi":"10.1016/j.icarus.2026.117026","DOIUrl":"10.1016/j.icarus.2026.117026","url":null,"abstract":"<div><div>The possibility of discovering evidence for life on Mars could be linked to its terrain and climate. A striking feature observed by planetary scientists is the polygonal cracks found on the surface of Mars. Deciphering the formation mechanism of these cracks can shed light on Martian early climatic conditions and geological history. This study aims to unravel the formation mechanisms of Mars intermediate-sized cracks (MICs) through a detailed comparison with multi-scale Earth desiccation cracks (EDCs), offering new insights into the geological processes and climatic conditions of early Mars. The integration of deep learning principles with quantitative analysis offers new insights into the morphological similarities between EDCs and MICs. The comprehensive analysis reveals that the investigated MICs exhibit characteristics indicative of water drying process similar to EDCs, further providing additional evidence of liquid water activity and an extreme arid climate in Martian early history. Furthermore, the findings suggest that the region of Mars under investigation underwent periods of heightened hydrological activity and warmer conditions in the past compared to current observations. This study provides a novel perspective on the significant loss of liquid water on Mars, which not only enriches the understanding of Martian hydrological history, but also has significant implications for the search for extraterrestrial life.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117026"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ejecta plume evolution in the Hayabusa2 impact experiment on asteroid Ryugu","authors":"Shota Kikuchi ,&nbsp;Masahiko Arakawa ,&nbsp;Koji Wada ,&nbsp;Toshihiko Kadono ,&nbsp;Seiji Sugita ,&nbsp;Kei Shirai ,&nbsp;Ko Ishibashi ,&nbsp;Rie Honda ,&nbsp;Yasuhiro Yokota ,&nbsp;Yuri Shimaki ,&nbsp;Naoya Sakatani ,&nbsp;Kazunori Ogawa ,&nbsp;Hirotaka Sawada ,&nbsp;Takanao Saiki ,&nbsp;Yuya Mimasu ,&nbsp;Yuto Takei ,&nbsp;Naru Hirata ,&nbsp;Satoru Nakazawa ,&nbsp;Makoto Yoshikawa ,&nbsp;Satoshi Tanaka ,&nbsp;Yuichi Tsuda","doi":"10.1016/j.icarus.2026.117023","DOIUrl":"10.1016/j.icarus.2026.117023","url":null,"abstract":"&lt;div&gt;&lt;div&gt;In 2019, Hayabusa2 performed an artificial cratering experiment on asteroid Ryugu by using a small carry-on impactor (SCI). This study focuses on the impact ejecta plume captured by a deployable camera (DCAM3) and investigates its dynamical evolution. In contrast to previous direct kinetic impact missions, the rendezvous configuration enabled high-resolution and comprehensive observations, thereby allowing the empirical validation of impact-physics models under actual space conditions. The image-based analyses are divided into two components: (1) reconstruction of the shape of the ejecta curtain composed of fine particles and (2) estimation of the trajectories of decimeter-scale boulders detected as individual bright spots. In the former analysis, the material constants associated with the ejecta velocity scaling law for the gravity-dominated regime are estimated through numerical fitting to the observed curtain edge. The distance-dependent ejection angle is simultaneously derived, constraining the kinematics of the excavation flow. The latter analysis aims to determine the ballistic trajectories of four ejected boulders based on their image plane centroid locations and nonlinear orbital dynamics. We examine the consistency between the estimated ejection velocities and angles of the boulders and the corresponding representative values for fine particles inferred from the ejecta curtain. The analysis results enable further discussion of ejecta deposition at the spacecraft landing site and of surface modification caused by secondary impacts of ejected boulders. In this study, remote sensing data obtained before, during, and after the SCI impact event are integrated to advance our understanding of the dynamic processes of impact ejecta, from excavation to deposition. A key finding of this study is that the ejecta velocity scaling parameters are &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;42&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;03&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;55&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;05&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. Also, the ejecta launch angle averages approximately &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;45&lt;/mn&gt;&lt;mo&gt;°&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, and its spatial variation is consistent with the surface topography. These results indicate that the SCI impact on Ryugu can be characterized as an impact on a typical sand target. Based on the Z-model for excavation with a best-fit streamline exponent of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Z&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;86&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, the ejecta deposit at the Hayabusa2 landing site was estimated to have a thickness of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and a maximum excavation depth of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, suggesting that the","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117023"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One hundred years of Venus polarimetry: PICSARR observations of the phase curves","authors":"Jeremy Bailey ,&nbsp;Daniel V. Cotton ,&nbsp;Kimberly Bott ,&nbsp;Ievgeniia Boiko","doi":"10.1016/j.icarus.2026.117043","DOIUrl":"10.1016/j.icarus.2026.117043","url":null,"abstract":"<div><div>We report new high-precision observations of the polarization of light scattered from the atmosphere of Venus, made 100 years after the pioneering studies by Bernard Lyot. The new observations include disk-integrated observations in a range of filters as well as imaging polarimetry. We compare the new results with past observations and models. We have reproduced the 1974 modeling of the Venus polarization by Hansen and Hovenier using modern radiative transfer codes. We show that the new models are in good agreement with the originals, and enable us to calculate the polarization for wavelengths not covered by the original study and to model the polarization distribution across the disk. The new observations are in good agreement with past determinations of the size distribution of the predominant particle mode. They agree with past studies in showing variability of the phase curve between synodic cycles and also polarization variability on short timescales, particularly at higher phase angles (crescent phases). Imaging polarimetry observations show good agreement with models for the redder wavelengths. However, observations in the ultraviolet show very different polarization behavior in the polar regions (within about 30°of the north and south poles). The simplest explanation of this result is that there is a larger Rayleigh scattering component in the polar regions than in the equatorial and mid-latitudes and this could be explained by a lower cloud-top height in agreement with previous spacecraft observations. These ultraviolet polarization observations are inconsistent with horizontally homogeneous atmospheric models.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117043"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Retention of water ice in lunar permanent shadowed regions","authors":"Sunpeng Zhou ,&nbsp;Zhenpeng Wang ,&nbsp;Shanshan Zhou ,&nbsp;Hang Deng ,&nbsp;Qinggong Wang ,&nbsp;Rui Wu ,&nbsp;Wei Yao ,&nbsp;Ke Xu","doi":"10.1016/j.icarus.2026.117022","DOIUrl":"10.1016/j.icarus.2026.117022","url":null,"abstract":"<div><div>Lunar polar regions are considered promising areas where massive water resources may exist, especially in the permanently shadowed regions (PSRs) where ice can hardly evaporate once formed due to the extremely low temperature. Here we estimate the ice retention by simulating the evolution of potential water ice reserves in PSRs in up to one billion years based on a simple numerical model. Dissipation at the warmer edge of PSRs and vapor supply from lower latitudes are identified as major mechanisms of ice spatial distribution evolution. We investigate the effects of PSRs sizes, boundary temperature, initial ice saturation, effective diffusion coefficient, the water vapor influx, and the reflected / scatted solar radiation from crater wall. Major findings include:<ul><li><span>1.</span><span><div>In large cold traps (radius greater than 20 m), most initially trapped water ice can be preserved, that may serve as major water supply for human activity; in micro cold traps (radius smaller than 1 m), water ice may only remain temporarily.</div></span></li><li><span>2.</span><span><div>Mixing between ice in shallow regolith and in deep regolith in PSRs is very limited, which can be utilized for investigating their distinct geological origins.</div></span></li></ul></div><div>This approach can also be extended to study other volatiles on extraterrestrial bodies in cold traps.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117022"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Saturn’s rings age, I: Reconsideration of the exposure age","authors":"Gregorio Ricerchi ,&nbsp;Aurélien Crida","doi":"10.1016/j.icarus.2026.117029","DOIUrl":"10.1016/j.icarus.2026.117029","url":null,"abstract":"<div><div>At the end of the <em>Cassini</em> mission, Saturn’s rings have been claimed to be spectacularly young compared to the age of the Solar System: their unusual ice-rich composition corresponds to initially pure ice rings polluted by interplanetary dust particles for 100 to 400 Myr. Since then, this exposure age has been commonly accepted as the real age of the rings.</div><div>In this paper, we review the processes that are involved in determining the exposure age. We aim to see how the exposure age depends on various parameters and how relevant it is to define the real rings age. First, a new expression for the gravitational focusing onto planar rings, important parameter but crudely defined in the literature, is derived. Then, an analytical formula describing how the dust fraction varies with time in static or viscously evolving rings is provided, including possible vaporisation at impact. Finally, we introduce a cleaning process from space weathering to possibly alter dust and reduce its amount to make rings look younger than they are.</div><div>We first found that the gravitational focusing is 5 times less important than previously thought, which automatically increases the exposure age from 0.5 to 2 Gyr. Moreover, depending on the impact properties (vaporisation rate, space weathering efficiency), several billion years can easily be reached. Finally, we find that the dust fraction in the rings converges towards a finite value which, in particular with an efficient space weathering mechanism, can be close to the observed one in the current rings. In this case, neither the age nor the initial composition of the rings can be derived, and the measure of the dust fraction and bombardment rate only constrains the physical parameters of the impacts and the efficiency of the space weathering. As long as the latter parameters are not known, the exposure age argument in favour of young rings is completely undercut.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117029"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dust, gas activity and morphology of comet 12P/Pons–Brooks at heliocentric distances beyond 1.1 au","authors":"Marek Husárik ,&nbsp;Gulchehra Kokhirova ,&nbsp;Valerii Kleshchonok ,&nbsp;K. Aravind ,&nbsp;Firuza Rakhmatullaeva ,&nbsp;Margarita Safonova ,&nbsp;Oleksandra Ivanova ,&nbsp;Olena Shubina ,&nbsp;Arsenii Kasianchuk","doi":"10.1016/j.icarus.2026.117028","DOIUrl":"10.1016/j.icarus.2026.117028","url":null,"abstract":"<div><div>Comet 12P/Pons–Brooks is a periodic comet with an orbital period of approximately 71 years. Because of the period duration, aphelion of 35.3<!--> <!-->au, and highly inclined orbit <span><math><mrow><mo>(</mo><mn>74</mn><mo>.</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>∘</mo></mrow></msup><mo>)</mo></mrow></math></span>, it is classified as a Halley-type comet.</div><div>In this work, we present the results of the analysis of photometric and spectral observations of comet 12P/Pons–Brooks while it was at a heliocentric distance beyond 1.1<!--> <!-->au, before perihelion passage. Quasisynchronous observations were carried out from July 2023 to March 2024 using 0.61-m and 1.3-m telescopes at the Skalnaté Pleso Observatory, 1-m telescope Zeiss-1000 Sanglokh International Astronomical Observatory, and 0.7-m telescope AZT8 at the observation station of Taras Shevchenko National University of Kyiv. Photometric observations were conducted using B, V, and R filters of the Johnson–Cousins and Bessel photometric systems. We completed our data collection with broadband photometric and spectral observations on the 2-m HCT telescope at the Indian Astronomical Observatory.</div><div>During this period, the dust coma morphology and photometric data measured in the R filter, such as the apparent, absolute magnitudes and dust activity level, indicate several repeated outbursts in brightness and dust activity occurred around July 22, September 25, October 17–23, and a significant outburst was recorded on November 1–7. We detected strong gas emission features in the cometary spectrum belonging to CN, C₂, and C₃ molecules. Furthermore, gas production rates of these molecules were estimated using Haser’s model. A comparison of dust activity level and CN gas production rate shows that dust activity increased significantly as the comet approached the Sun, while gas activity exhibited more moderate changes.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"452 ","pages":"Article 117028"},"PeriodicalIF":3.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387864","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}