Icarus最新文献

{"title":"Major brightening events in Jupiter’s sodium nebula during Juno era","authors":"","doi":"10.1016/j.icarus.2024.116301","DOIUrl":"10.1016/j.icarus.2024.116301","url":null,"abstract":"<div><p>Successive observations of Jupiter’s sodium nebula have identified several brightening events, presumably due to variability in Io’s volcanic plumes. An event that began in the beginning of March 2018 has been already reported by Morgenthaler et al. (2019,2024a,2024b). In this work, we found that this event was followed by another one. By adding these observations, details of these events including one observed by Morgenthaler et al. (2019,2024a,2024b) are described herein. Especially, the event in 2018 seems to have been the strongest enhancement during Juno spacecraft’s orbital mission, at least before 2020. Also, our observations show that the D-line brightness of the sodium nebula was decreasing in early September, 2019. This tendency is consistent with Io’s volcanic plume activity observed by Atacama Large (sub)Millimeter Array (ALMA). The KCl gas observed in this plume with ALMA is a chemical analog of NaCl, which is believed to be the parent molecule that dissociates to form the sodium nebula. While these observations are not the direct evidence of plume supply to sodium nebula, they are suggestive of control of Io’s volcanic plumes on the brightness of Jupiter’s sodium nebula.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0019103524003610/pdfft?md5=d160c29dbf39ac042be80f1a26f94066&pid=1-s2.0-S0019103524003610-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142169268","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}

{"title":"Methane storm characteristics and evolution in simulations of Titan’s hydroclimate","authors":"","doi":"10.1016/j.icarus.2024.116290","DOIUrl":"10.1016/j.icarus.2024.116290","url":null,"abstract":"<div><p>Methane precipitation is a key component of the climate on Titan, and has been shown to impact surface features. Recent general circulation models (GCMs) have reproduced Titan’s hydroclimate, including precipitation, with increasing accuracy, yet characterization of their simulated precipitation events is lacking. We investigate the characteristics and evolution of methane storms simulated over 40 Titan years using the Titan Atmospheric Model, a validated GCM. Storms are identified and tracked using the density-based spatial clustering of applications with noise (DBSCAN) algorithm, allowing them to be followed through time and space. We find that storms follow seasonality expected from observations and prior modeling, occur preferentially in the summer hemisphere, and tend to start over high topography. The population of storms is bimodal in traits corresponding to intensity, area, and duration, with a large population of small, short-lived, and weakly precipitating storms and a smaller population of exceptionally large, long-lasting, and intense storms. These largest storms tend to evolve similarly over their lifetimes, peaking early in intensity and in the middle of their lives in area. We also find temporal clustering of storms, in alignment with observations and the proposed relaxation-oscillation model of Titan’s methane precipitation. These storm clusters emerge quasi-periodically following long dry spells during which evaporation of surface methane recharges atmospheric moisture. Approximately five clusters occur per Titan year, and their locations are strongly seasonal. Overall, our quantitative descriptions of storms and storm clusters over a long timescale provide additional insight into Titan’s methane cycle and surface features, and may assist in the planning of future missions such as <em>Dragonfly</em>.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151776","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":"Corrigendum to “The interaction of deep convection with the general circulation in Titan’s atmosphere, Part II: Impacts on the climate”","authors":"","doi":"10.1016/j.icarus.2024.116264","DOIUrl":"10.1016/j.icarus.2024.116264","url":null,"abstract":"","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0019103524003245/pdfft?md5=081000ec27d06caf59881be2795a9dc1&pid=1-s2.0-S0019103524003245-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142122406","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}

{"title":"Rock thermal conductivity and thermal inertia measurements under martian atmospheric pressures","authors":"","doi":"10.1016/j.icarus.2024.116272","DOIUrl":"10.1016/j.icarus.2024.116272","url":null,"abstract":"<div><p>The physical properties of rocks on planetary surfaces influence their bulk thermal conductivity (<em>k</em>) and thermal inertia (<em>TI</em>); however, there has been little work done to date to explore quantitative relationships between physical properties (bulk density, porosity, mechanical strength) and thermal properties (<em>k</em> and <em>TI</em>) at Mars-relevant pressures. We present the first <em>k</em> and <em>TI</em> measurements of a comprehensive suite of Mars-relevant igneous and sedimentary rocks under Mars atmospheric pressures. We used modified transient plane source (MTPS) and transient plane source (TPS) methods to measure <em>k</em> and <em>TI</em> values of 40 samples (3 monomineralic, 13 igneous, 24 sedimentary) at pressures between 1 and 10 mbar and at 1 bar, at ∼25 °C. The rock samples were characterized by bulk density, grain density, porosity, uniaxial compressive strength, mineralogy, and major and trace element abundances. We find that bulk density and porosity roughly correlate to <em>k</em> and <em>TI</em> values at Mars pressures by power law relationships. The relationships of the thermal properties with mechanical strength and chemical properties, however, are not straightforward. Many physical and chemical factors play a role in determining <em>k</em> and <em>TI</em> values; thus, it is not possible to relate a single physical or chemical property to <em>k</em> and <em>TI</em> directly based on these measurements. Rock <em>TI</em> values derived from rover surface temperature measurements on Mars agree with our results for similar rock types.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162315","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":"Dynamical evolution of the Uranian satellite system I.","authors":"","doi":"10.1016/j.icarus.2024.116282","DOIUrl":"10.1016/j.icarus.2024.116282","url":null,"abstract":"<div><p>Mutual gravitational interactions between the five major Uranian satellites raise small quasi-periodic fluctuations on their orbital elements. At the same time, tidal interactions between the satellites and the planet induce a slow outward drift of the orbits, while damping the eccentricities and the inclinations. In this paper, we revisit the current and near past evolution of this system using a <span><math><mrow><mi>N</mi><mo>−</mo></mrow></math></span>body integrator, including spin evolution and tidal dissipation with the weak friction model. We update the secular eigenmodes of the system and show that it is unlikely that any of the main satellites were recently captured into a high obliquity Cassini state. We rather expect that the Uranian satellites are in a low obliquity Cassini state and compute their values. We also estimate the current variations in the eccentricities and inclinations, and show that they are not fully damped. We constrain the modified quality factor of Uranus to be <span><math><mrow><msubsup><mrow><mi>Q</mi></mrow><mrow><mi>U</mi></mrow><mrow><mo>′</mo></mrow></msubsup><mo>=</mo><mrow><mo>(</mo><mn>1</mn><mo>.</mo><mn>2</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>4</mn><mo>)</mo></mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span>, and that of Ariel to be <span><math><mrow><msubsup><mrow><mi>Q</mi></mrow><mrow><mi>A</mi></mrow><mrow><mo>′</mo></mrow></msubsup><mo>=</mo><mrow><mo>(</mo><mn>7</mn><mo>±</mo><mn>3</mn><mo>)</mo></mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span>. We find that the system most likely encountered the 5/3 mean motion resonance between Ariel and Umbriel in the past, at about <span><math><mrow><mo>(</mo><mn>0</mn><mo>.</mo><mn>7</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>2</mn><mo>)</mo></mrow></math></span> Gyr ago. We additionally determine the eccentricities and inclinations of all satellites just after the resonance passage that comply with the current system. We finally show that, from the crossing of the 5/3 MMR to the present, the evolution of the system is mostly peaceful and dominated by tides raised on Uranus by the satellites.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0019103524003427/pdfft?md5=67d5833993d4db688b503b98b01d594d&pid=1-s2.0-S0019103524003427-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152016","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}

{"title":"New gravity field of comet 67P/C-G based on Rosetta’s Doppler and optical data","authors":"","doi":"10.1016/j.icarus.2024.116284","DOIUrl":"10.1016/j.icarus.2024.116284","url":null,"abstract":"<div><p>The gravity field of a celestial body gives valuable insights into its fundamental properties such as its density and internal structure. The Doppler data collected by the Radio-Science Investigation (RSI) experiment of the Rosetta mission were previously used to determine the gravity field of comet 67P/Churyumov–Gerasimenko up to degree 2 (Pätzold et al., 2016). In the present study we re-estimate the gravity field of 67P/C-G using not only RSI data as before, but also images data from Rosetta’s OSIRIS camera. These data, converted into “landmark” observations, are complementary to RSI data. Therefore, the analysis of combined Doppler and optical data results in a significant improvement in the restitution of Rosetta’s orbit and the determination of the comet gravity field with respect to previous work. Some coefficients of the comet’s gravity field are now resolved up to degree 4. The mass and low degrees estimates are in fairly good agreement with those previously published, but the improvement in their accuracy (i.e. lower sigmas) as well as the better resolution (i.e. maximum degree) of the new gravity field suggests that the distribution of mass in the nucleus may not be uniform, contrary to what was previously thought. Moreover, we estimate a change in the mass of the comet attributed to ice sublimation at its orbital perihelion that is almost three times greater than that previously published. The new estimated mass loss is <span><math><mrow><mi>Δ</mi><mi>M</mi><mo>=</mo><mn>28</mn><mo>.</mo><mn>0</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>29</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>9</mn></mrow></msup><mspace></mspace><mi>kg</mi></mrow></math></span>, corresponding to 0.28% of the total mass of the comet. Thanks to a precise determination of the degree-1 gravity coefficients, we observe for the first time a motion of the center of mass of the comet by <span><math><mrow><mo>∼</mo><mn>35</mn><mspace></mspace><mi>m</mi></mrow></math></span> northward that could be explained by a more pronounced outgassing activity in the south of the comet due to the orientation of its spin axis relative to the Sun. The temporal evolution (before versus after perihelion) of the other estimated gravity coefficients and in particular degree-2 is more modest (0.8% for <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>20</mn></mrow></msub></math></span> and 2% for <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>22</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>22</mn></mrow></msub></math></span>).</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151909","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":"Evidence of a Martian spatter cone south of Pavonis Mons","authors":"","doi":"10.1016/j.icarus.2024.116286","DOIUrl":"10.1016/j.icarus.2024.116286","url":null,"abstract":"<div><p>Spatter cones are a common mafic explosive volcanic feature observed on Earth associated with Hawaiian and Strombolian-style lava fountaining. Across Mars there are numerous explosive volcanic features assessed to be accumulations of cold pyroclasts (e.g., scoria cones, tuff rings) but identification of welded and fused explosive deposits (i.e., spatter) has only recently been investigated. We present evidence indicating the presence of a Martian spatter cone south of Pavonis Mons and a comparison to a spatter cone formed during the 2021 Fagradalsfjall eruption, Iceland. The morphology and morphometry of the possible Martian spatter cone are more consistent with agglutinated rock like the spatter cone formed during the Fagradalsfjall eruption than poorly consolidated tephra, characteristic of scoria cones. In addition, the size of the two spatter cones falls within anticipated dimensions based on a simple ballistic trajectory model. Evidence for spatter included high angled slopes, knobby yet layered surface textures, rounded boulder talus, and thermophysical properties consistent with material that is more indicative of rock than scoria. The evidence indicates that the volcanic feature South of Pavonis Mons should be classified as a spatter cone. Identification of a Martian spatter cone has implications for eruption dynamics, magmatic volatile content, and environmental conditions.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0019103524003464/pdfft?md5=75d7e7702bddf8ff8a471d18abbbc5fe&pid=1-s2.0-S0019103524003464-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095070","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}

{"title":"Identification and preliminary characterisation of signals recorded by instrument for lunar seismic activity at the Chandrayaan 3 landing site","authors":"","doi":"10.1016/j.icarus.2024.116285","DOIUrl":"10.1016/j.icarus.2024.116285","url":null,"abstract":"<div><p>The science objective of the Instrument for Lunar Seismic Activity (ILSA) is to study the seismicity at the landing site of the Indian lunar mission, the Chandrayaan 3. It also aimed at demonstrating the capability of devices based on silicon micromachining technology to survive and operate in planetary missions and environments. The Chandrayaan 3 mission had a lander and a rover together carrying five different scientific instruments. ILSA was placed on the lunar surface and had six accelerometers in it. It was operated during the lunar day from 24 August 2023 to 4 September 2023. This paper presents the summary of observations made on 190 h of data recorded by ILSA. We have identified more than 250 distinct signals of which about 200 signals are correlated to known activities involving the physical movements of the rover or the operation of science instruments. This paper presents our approach in the preliminary characterisation and cataloguing of the events based on their temporal properties and spectral contents. It will also act a guide for the future researchers to search, identify and analyse the records made by ILSA.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142122404","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":"Moisture cycles in Jezero crater, Mars","authors":"","doi":"10.1016/j.icarus.2024.116283","DOIUrl":"10.1016/j.icarus.2024.116283","url":null,"abstract":"<div><p>Diurnal and annual water cycles are studied during the first year of Perseverance rover in Jezero, using observations from the Mars Environmental Dynamics Analyzer (MEDA) and column modeling. Areal values for the ground thermal inertia (TI) and albedo are first found at one site by fitting model temperatures to the observed air temperatures. Areal soil porosity and the initial water vapor volume mixing ratios (vmr) are next found via model-vmr fits to the observation-based vmr. The meteorology and physics of the modeled air and subsurface diurnal moisture cycle at the site is then discussed in detail. The process of fit to observations is finally extended to fourteen sites along the Perseverance track, resulting in estimates for areal TI, albedo and porosity at these sites, and in MEDA-based initial estimates for the annual and diurnal moisture cycles at Jezero during MY36.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097791","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":"Site selection for the second Flyeye telescope: A simulation study for optimizing near-earth object discovery","authors":"","doi":"10.1016/j.icarus.2024.116281","DOIUrl":"10.1016/j.icarus.2024.116281","url":null,"abstract":"<div><p>The European Space Agency (ESA) is developing a network of wide-field survey telescopes, named Flyeye, to improve the discovery of Near-Earth Objects (NEOs). The first telescope in the network will be located in the Northern Hemisphere on Mount Mufara (Italy), and a second Flyeye telescope, featuring increased detection capabilities, has just started the critical design phase.</p><p>The potential location for the second Flyeye telescope is investigated by performing simulations of NEOs on impacting trajectories. Approximately 3000 impacting asteroids of two absolute magnitudes (H = 25 and H = 28) were propagated and tested for detectability by major existing surveys (Catalina, Pan-STARRS, ATLAS), the upcoming Vera Rubin Observatory (LSST), and possible Flyeye locations. Chile, South Africa, and a second facility in the Northern Hemisphere were considered. For each observatory, their past or planned pointing strategies were taken into account in the simulation.</p><p>Before LSST deployment, a single Flyeye in the Southern Hemisphere performs similarly to a telescope in the Northern Hemisphere. When combined, having one telescope in the north and one in the south maximizes detections and number of unique objects detected. After LSST, southern and northern Flyeye telescopes remain complementary. Overall, simulations show that a second Flyeye in the south complements a Flyeye telescope in the north both before and after LSST. A Flyeye located at La Silla would take advantage of the excellent atmospheric conditions, while allowing a balance of assets across hemispheres.</p></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151940","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}