111 research outputs found
Evolution of impact melt pools on Titan - data files
No full textData files to produce figures in the manuscript entitled 'Evolution of impact melt pools on Titan' written by Klara Kalousova, Shigeru Wakita, Christophe Sotin, Catherine D. Neish, Jason M. Soderblom, Ondrej Soucek, and Brandon C. Johnson and submitted to Journal of Geophysical Research: Planets.This work was supported by the Czech Science Foundation through project No. 22-20388S (KK, OS) and through NASA Cassini Data Analysis Program grant 80NSSC20K0382 (SW, CDN, JMS, BCJ). This research was triggered by discussions during the meeting in Bern of the International Space Science Institute (ISSI) International Team `The habitability of Titan's subsurface water ocean'. We gratefully acknowledge the developers of iSALE-2D, including Gareth Collins, Kai W\"{u}nnemann, Dirk Elbeshausen, Tom Davison, Boris Ivanov, and Jay Melosh (https://isale-code.github.io). This research was supported in part through computational resources provided by Information Technology at Purdue, West Lafayette, Indiana
Geology of the Selk crater region on Titan from Cassini VIMS observations
No full textInternational audienceObservations of Titan obtained by the Cassini Visual and Infrared Mapping Spectrometer (VIMS) have revealed Selk crater, a geologically young, bright-rimmed, impact crater located similar to 800 km north-northwest of the Huygens landing site. The crater rim-crest diameter is 90 km; its floor diameter is similar to 60 km. A central pit/peak, 20-30 km in diameter, is seen; the ratio of the size of this feature to the crater diameter is consistent with similarly sized craters on Ganymede and Callisto, all of which are dome craters. The VIMS data, unfortunately, are not of sufficient resolution to detect such a dome. The inner rim of Selk crater is fluted, probably by eolian erosion, while the outer flank and presumed ejecta blanket appear dissected by drainages (particularly to the east), likely the result of fluvial erosion. Terracing is observed on the northern and western walls of Selk crater within a 10-15 km wide terrace zone identified in VIMS data; the terrace zone is bright in SAR data, consistent with it being a rough surface. The terrace zone is slightly wider than those observed on Ganymede and Callisto and may reflect differences in thermal structure and/or composition of the lithosphere. The polygonal appearance of the crater likely results from two preexisting planes of weakness (oriented at azimuths of 21 degrees and 122 degrees east of north). A unit of generally bright terrain that exhibits similar infrared-color variation and contrast to Selk crater extends east-southeast from the crater several hundred kilometers. We informally refer to this terrain as the Selk "bench." Both Selk and the bench are surrounded by the infrared-dark Belet dune field. Hypotheses for the genesis of the optically bright terrain of the bench include: wind shadowing in the lee of Selk crater preventing the encroachment of dunes, impact-induced cryovolcanism, flow of a fluidized-ejecta blanket (similar to the bright crater outflows observed on Venus), and erosion of a streamlined upland formed in the lee of Selk crater by fluid flow. Vestigial circular outlines in this feature just east of Selk's ejecta blanket suggest that this might be a remnant of an ancient, cratered crust. Evidently the southern margin of the feature has sufficient relief to prevent the encroachment of dunes from the Belet dune field. We conclude that this feature either represents a relatively high-viscosity, fluidizedejecta flow (a class intermediate to ejecta blankets and long venusian-style ejecta flows) or a streamlined upland remnant that formed downstream from the crater by erosive fluid flow from the west-northwest
Titan’s “Magic islands”. Transient features in a hydrocarbon sea
No full textThe region of Titan's hydrocarbon sea, Ligeia Mare, where transient bright features were previously discovered, was anomalously bright in the first of two more recent Cassini RADAR observations but not the second. Another transient bright feature in a different region of Ligeia Mare was also discovered in the first of the new observations. Here we present all the high-resolution observations of the regions containing these transient features and the quantitative constraints that we derived from them. We argue that these features are unlikely to be SAR image artifacts or permanent geophysical structures and thus their appearance is the result of ephemeral phenomena on Titan. We find that the transient features are more consistent with floating and/or suspended solids, bubbles, and waves than tides, sea level change, or seafloor change and based on the frequency of these phenomena in terrestrial settings, we consider waves to be the most probable hypothesis. These transient features are the first instance of active processes in Titan's lakes and seas to be confirmed by multiple detections and demonstrate that Titan's seas are not stagnant but rather dynamic environments
Cassini Bistatic Radar Observations of Titan's Seas: Results about Dielectric Properties and Capillary Waves Detection
No full textDigital Elevation Model Data from: Measuring Erosional and Depositional Patterns Across Comet 67P's Imhotep Region
No full textRecommended citation for this dataset:
Abhinav Jindal, Samuel Birch, Alexander Hayes, Fiona P. Özyurt, Adam Issah, Megan Barrington, Jason Soderblom, Randolph Kirk, Raphael Marschall, Jean-Baptiste Vincent. (2023) Digital Elevation Model Data from: Measuring Erosional and Depositional Patterns Across Comet 67P's Imhotep Region. [dataset] Cornell University eCommons Repository. https://doi.org/10.7298/qgyq-ym43These files contain the Digital Elevation Model (DEM) data for the results reported in Jindal et al. Measuring Erosional and Depositional Patterns Across Comet 67P's Imhotep Region. In Jindal et al. we found: Comet 67P/Churyumov-Gerasimenko displays a pronounced hemispherical dichotomy in surface morphology where the southern hemisphere exhibits more erosional features than the northern hemisphere due to receiving much greater solar radiation. Consequently, it is generally assumed that particles are ejected from the southern hemisphere through sublimation and a significant fraction eventually descends as airfall, covering the northern terrains. To investigate this south-to-north material transfer during the comet's perihelion passage, we use photoclinometry to measure material redistribution within its most extensive smooth terrain deposit around the Imhotep region. However, our findings do not align with this expected trend. Instead, we show that local-scale processes substantially impact the erosion and accumulation of material, with one area experiencing net erosion while another nearby region, just a few dozen meters away, sees sediment buildup. Our analysis underscores the complex interplay of processes shaping Comet 67P's surface, and likely comets more generally.This research was supported by the Rosetta Data Analysis Program (80NSSC19K1307) and the Heising-Simons Foundation (51 Pegasi b Fellowship to S.P.D.B)
Europa Deep Dive Two
No full textThe focus of the Europa Deep Dive 2: Composition workshop is to assess existing laboratory data and identify gaps where laboratory work is still needed; assess existing data on the Europa surface and exosphere; plan how to realize the needs for new data; encourage dialogue among laboratory, observational, and data-analysis communities; and foster collaborations among complementary laboratories.Institutional Support Lunar and Planetary Institute, Universities Space Research Association ; Conveners Louise M. Prockter, USRA/Lunar and Planetary Institute, Jonathan Kay, USRA/Lunar and Planetary Institute ; Science Organizing Committee Murthy S. Gudipati, NASA Jet Propulsion Laboratory, Reggie L. Hudson, NASA Goddard Space Flight Center, Lynnae C. Quick, Smithsonian Institution/Air and Space Museum, Abigal M. Rymer, Johns Hopkins University/Applied Physics Laboratory, Jason M. Soderblom, Massachusetts Institute of Technology.PARTIAL CONTENTS: Towards a Better Understanding of Composition: Status Update on Laboratory Studies of Europa Environment Analogs / B. L. Henderson -- Laboratory Spectral Measurements Needed to Better Model Europa's Surface Composition / C. A. Hibbitts -- Impurities in Europa's Ice Shell: Salty Tree-Rings? / S. M. Howell and E. J. Leonard -- Diving Deep into Europa's Reaction Chemistry / R. L. Hudson -- Plasma and Thermal Processing of Europa's Surface / R. E. Johnson, A. Oza, C. Schmidt, and F. Leblanc -- Investigating the Surface Composition of Europa with the Europa Clipper / R. L. Klima, J. Soderblom, M. Gudipati, and Europa Clipper Composition Working Group -- New Constraints on the Abundances of Sulfur and Chlorine at Europa / M. A. McGrath, W. B. Sparks, and J. R. Spencer -- Melt Production, Eruption and Degassing from Europa's Interior: Effects on Composition over Time / M. Melwani Daswani and S. D. Vance -- Investigating Detectability of Organics on Europa's Surface / I. Mishra and J. Lunine -- Rifting, Convection, and the Elevation of Bands on Europa / L. G. J. Montesi, S. M. Howell, and R. T. Pappalardo
Exploration of Enceladus and Titan: investigating ocean worlds’ evolution and habitability in the Saturn system
No full textWe present a White Paper with a science theme concept of ocean world evolution and habitability proposed in response to ESA’s Voyage 2050 Call with a focus on Titan and Enceladus in the Saturn system. Ocean worlds in the outer Solar System that possess subsurface liquid water oceans are considered to be prime targets for extra-terrestrial life and offer windows into Solar System evolution and habitability. The Cassini-Huygens mission to the Saturn system (2004–2017) revealed Titan with its organic-rich evolving world with terrestrial features and Enceladus with its active aqueous environment to be ideal candidates to investigate ocean world evolution and habitability. Additionally, this White Paper presents a baseline for a multiple flyby mission with a focused payload as an example of how ocean world evolution and habitability in the Saturn system could be investigated building on the heritage of the Cassini-Huygens mission and complementing the recently selected NASA Dragonfly mission
Interactions between complex craters and the lunar crust: Analysis using GRAIL data
No full textA high-resolution gravity map over the entire lunar surface has been derived from data acquired by the Gravity Recovery and Interior Laboratory (GRAIL) mission. Soderblom et al. (2015) showed that crater Bouguer gravity anomalies scale with crater diameter and porosity for craters in the lunar highlands. Here we extend this study globally, examining complex craters in each of the three lunar terranes: highlands, maria, and the South Pole-Aitken basin. We find that craters within South Pole-Aitken basin and in the lunar maria have statistically different Bouguer anomalies from those in the lunar highlands. These differences are best explained by differences in crustal porosity among the three terranes. Though there is still much unresolved scatter in the data, we find that no other lunar material properties (crustal thickness, density gradient, etc.) are able to improve our model fit to the data.GRAIL project; NASA [NNX15AP90G, NNX12AL08G]First Published: 25 August 2016; 6 Month Embargo.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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Identification of buried lunar impact craters from GRAIL data and implications for the nearside maria
No full textGravity observations from the dual Gravity Recovery and Interior Laboratory (GRAIL) spacecraft have revealed more than 100 quasi‐circular mass anomalies, 26–300 km in diameter, on the lunar nearside. These anomalies are interpreted to be impact craters filled primarily by mare deposits, and their characteristics are consistent with those of impact structures that formed prior to, and during, intervals of flooding of feldspathic terrane by mare basalt lavas. We determine that mare deposits have an average density contrast of 850⁺³⁰⁰₋₂₀₀ kg m⁻³ relative to the surrounding crust. The presence of a large population of volcanically buried craters with minimal topographic expression and diameters up to 300 km requires an average nearside mare thickness of at least 1.5 km and local lenses of mare basalt as thick as ~7 km
USGS High-Resolution Topomapping of Mars with Mars Orbiter Camera Narrow-Aangle Images
No full textWe describe our initial experiences producing controlled digital elevation models (DEMs) of Mars with horizontal resolutions of ≤10 m and vertical precisions of ≤2 m. Such models are of intense interest at all phases of Mars exploration and scientific investigation, from the selection of safe landing sites to the quantitative analysis of the morphologic record of surface processes. Topomapping with a resolution adequate to address many of these issues has only become possible with the success of the Mars Global Surveyor (MGS) mission. The Mars Orbiter Laser Altimeter (MOLA) on MGS mapped the planet globally with absolute accuracies <10 m vertically and ~100 m horizontally but relatively sparse sampling (300 m along track, with gaps of>1 km between tracks common at low latitudes). We rely on the MOLA data as the best available source of control and process images from the narrow-angle Mars Orbiter Camera (MOC-NA) with stereo and photoclinometric (shape-from-shading) techniques to produce DEMs with significantly better horizontal resolution. The techniques described here enable mapping not only with MOC but also with the high-resolution cameras (Mars Express HRSC, Mars Reconnaissance Orbiter HiRISE) that will orbit Mars in the next several years. * Correspondence author
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