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1. Feasibility of Passive Sounding of Uranian Moons using Uranian Kilometric Radiation

Author

Romero-Wolf, Andrew, Steinbruegge, Gregor, Castillo-Rogez, Julie, Cochrane, Corey J., Nordheim, Tom A., Mitchell, Karl L., Wolfenbarger, Natalie S., Schroeder, Dustin M., and Peters, Sean T.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present a feasibility study for passive sounding of Uranian icy moons using Uranian Kilometric Radio (UKR) emissions in the 100 - 900 kHz band. We provide a summary description of the observation geometry, the UKR characteristics, and estimate the sensitivity for an instrument analogous to the Cassini Radio Plasma Wave Science (RPWS) but with a modified receiver digitizer and signal processing chain. We show that the concept has the potential to directly and unambiguously detect cold oceans within Uranian satellites and provide strong constraints on the interior structure in the presence of warm or no oceans. As part of a geophysical payload, the concept could therefore have a key role in the detection of oceans within the Uranian satellites. The main limitation of the concept is coherence losses attributed to the extended source size of the UKR and dependence on the illumination geometry. These factors represent constraints on the tour design of a future Uranus mission in terms of flyby altitudes and encounter timing.

Published
2023

3. Hypotheses for Triton's Plumes: New Analyses and Future Remote Sensing Tests

Author

Hofgartner, Jason D., Birch, Samuel P. D., Castillo, Julie, Grundy, Will M., Hansen, Candice J., Hayes, Alexander G., Howett, Carly J. A., Hurford, Terry A., Martin, Emily S., Mitchell, Karl L., Nordheim, Tom A., Poston, Michael J., Prockter, Louise M., Quick, Lynnae C., Schenk, Paul, Schindhelm, Rebecca N., and Umurhan, Orkan M.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Physics - Geophysics
Abstract

At least two active plumes were observed on Neptune's moon Triton during the Voyager 2 flyby in 1989. Models for Triton's plumes have previously been grouped into five hypotheses, two of which are primarily atmospheric phenomena and are generally considered unlikely, and three of which include eruptive processes and are plausible. These hypotheses are compared, including new arguments, such as comparisons based on current understanding of Mars, Enceladus, and Pluto. An eruption model based on a solar-powered, solid-state greenhouse effect was previously considered the leading hypothesis for Triton's plumes, in part due to the proximity of the plumes to the subsolar latitude during the Voyager 2 flyby and the distribution of Triton's fans that are putatively deposits from former plumes. The other two eruption hypotheses are powered by internal heat, not solar insolation. Based on new analyses of the ostensible relation between the latitude of the subsolar point on Triton and the geographic locations of the plumes and fans, we argue that neither the locations of the plumes nor fans are strong evidence in favor of the solar-powered hypothesis. We conclude that all three eruption hypotheses should be considered further. Five tests are presented that could be implemented with remote sensing observations from future spacecraft to confidently distinguish among the eruption hypotheses for Triton's plumes. The five tests are based on the: (1) composition and thickness of Triton's southern hemisphere terrains, (2) composition of fan deposits, (3) distribution of active plumes, (4) distribution of fans, and (5) surface temperature at the locations of plumes and/or fans. The tests are independent, but complementary, and implementable with a single flyby mission such as the Trident mission concept. We note that, in the case of the solar-driven hypothesis, the 2030s and 2040s may be the last ..., Comment: Accepted for publication in Icarus

Published
2021
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4. The microstructural evolution of water ice in the solar system through sintering

Author

Molaro, Jamie L., Choukroun, Mathieu, Phillips, Cynthia B., Phelps, Eli S., Hodyss, Robert, Mitchell, Karl L., Lora, Juan M., and Meirion-Griffith, Gareth

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Ice sintering is a form of metamorphism that drives the microstructural evolution of an aggregate of grains through surface and volume diffusion. This leads to an increase in the grain-to-grain contact area ("neck") and density of the aggregate over time, resulting in the evolution of its strength, porosity, thermal conductivity, and other properties. This process plays an important role in the evolution of icy planetary surfaces, though its rate and nature are not well constrained. In this study, we explore the model of Swinkels and Ashby (1981), and assess the extent to which it can be used to quantify sintering timescales for water ice. We compare predicted neck growth rates to new and historical observations of ice sintering, and find agreement to some studies at the order of magnitude level. First-order estimates of neck growth timescales on planetary surfaces show that ice may undergo significant modification over geologic timescales, even in the outer solar system. Densification occurs over much longer timescales, suggesting some surfaces may develop cohesive, but porous, crusts. Sintering rates are extremely sensitive to temperature and grain size, occurring faster in warmer aggregates of smaller grains. This suggests that the microstructural evolution of ices may vary not only throughout the solar system, but also spatially across the surface and in the near-surface of a given body. Our experimental observations of complex grain growth and mass redistribution in ice aggregates point to components of the model that may benefit from improvement, and areas where additional laboratory studies are needed., Comment: Main Text 48 pages (17 figures, 8 tables, 2 appendices), 75 pages incl. Supplemental Information, Journal of Geophysical Research: Planets

Published
2019
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8. A Proposed Model for Cryovolcanic Activity on Enceladus Driven by Volatile Exsolution.

Author

Mitchell, Karl L., Rabinovitch, Jason, Scamardella, Jonathan C., and Cable, Morgan L.

Subjects
CHEMICAL processes, DYNAMIC pressure, FLUID mechanics, GEYSERS, PHYSICS, EXPLOSIVE volcanic eruptions
Abstract

There is considerable interest in sending a mission to Enceladus to sample its erupting materials, which are sourced from its ocean, a proposed habitable environment. However, we lack resolution between competing ascent and eruption models, which offer differing consequences and challenges for mission sampling and access strategies. We report a new Enceladus ascent and eruption model, "Cryo‐Erupt," where ascent from ocean to jet is driven by the exsolution and expansion of dissolved gases from ascending water within conduits. This mechanism shares many similarities with some forms of terrestrial activity, including explosive silicate volcanism, cold‐water geysers and "limnic" eruptions. This preliminary study suggests that this mode of ascent and eruption is viable and broadly consistent with a range of observations including the apparent co‐existence of point‐ (jet) and fissure‐ (curtain) sourced activity as well as strong contrasts in velocity and ice‐to‐vapor ratio between the plume and the jets feeding it. However, it requires the co‐existence of a sublimation plume as an additive component to the broader plume. The outcomes of the Cryo‐Erupt model differ in terms of conduit physical and chemical processes from previously proposed boiling interface eruption models, for example, predicting larger dynamic pressures and narrower conduits, which could present challenges for direct robotic access. Due to the lack of a static boiling interface or wall condensation, bulk composition is unlikely to change appreciably during ascent from the ocean‐conduit interface to the jet, potentially simplifying the interpretation of samples collected in space or on Enceladus' surface. Plain Language Summary: High‐speed jets from giant ice fissures on Saturn's moon Enceladus feed a large plume, which is of interest to scientists because it contains salts and organic compounds, which are evidence of a subsurface ocean that may possibly host life. However, it is unclear how the chemistry of the plume material (gas and grains) might be altered as this material moves from the ocean into space, and to what extent samples from the plume are representative of ocean composition. Previous models to predict this behavior mostly relied on boiling of water as the primary way that gas and droplets are ejected, but these models do not take into account all of the physics involved, and do not fully reproduce what Cassini observed at Enceladus. We propose a new model that instead invokes dissolved gas molecules expanding, similar to explosive volcanoes on Earth and essentially the same mechanism that causes cans of soda to explode upon opening if shaken. We predict that the erupting jets would largely preserve bulk ocean content and thus would be the best place to study ocean content, in contrast with the broader plume, which would have more water that has sublimated from the surface. Key Points: Recent studies on the ascent and eruption of Enceladus' plume have neglected the role of exsolution and expansion of dissolved volatilesVolatile‐driven direct ocean‐to‐jet liquid water ascent is generally consistent with observations if combined with a sublimation co‐plumeThis mode of ascent could preserve ocean bulk content in jets, leading to jet sampling strategies being preferred for future missions [ABSTRACT FROM AUTHOR]

Published
2024
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9. THEO Concept Mission: Testing the Habitability of Enceladus's Ocean

Author

MacKenzie, Shannon M., Caswell, Tess E., Phillips-Lander, Charity M., Stavros, E. Natasha, Hofgartner, Jason D., Sun, Vivian Z., Powell, Kathryn E., Steuer, Casey J., O'Rourke, Joesph G., Dhaliwal, Jasmeet K., Leung, Cecilia W. S., Petro, Elaine M., Wynne, J. Judson, Phan, Samson, Crismani, Matteo, Krishnamurthy, Akshata, John, Kristen K., DeBruin, Kevin, Budney, Charles J., and Mitchell, Karl L.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Saturn's moon Enceladus offers a unique opportunity in the search for life and habitable environments beyond Earth, a key theme of the National Research Council's 2013-2022 Decadal Survey. A plume of water vapor and ice spews from Enceladus's south polar region. Cassini data suggest that this plume, sourced by a liquid reservoir beneath the moon's icy crust, contain organics, salts, and water-rock interaction derivatives. Thus, the ingredients for life as we know it-- liquid water, chemistry, and energy sources-- are available in Enceladus's subsurface ocean. We have only to sample the plumes to investigate this hidden ocean environment. We present a New Frontiers class, solar-powered Enceladus orbiter that would take advantage of this opportunity, Testing the Habitability of Enceladus's Ocean (THEO). Developed by the 2015 Jet Propulsion Laboratory Planetary Science Summer School student participants under the guidance of TeamX, this mission concept includes remote sensing and in situ analyses with a mass spectrometer, a sub-mm radiometer-spectrometer, a camera, and two magnetometers. These instruments were selected to address four key questions for ascertaining the habitability of Enceladus's ocean within the context of the moon's geological activity: (1) How are the plumes and ocean connected? (2) Are the abiotic conditions of the ocean suitable for habitability? (3) How stable is the ocean environment? (4) Is there evidence of biological processes? By taking advantage of the opportunity Enceladus's plumes offer, THEO represents a viable, solar-powered option for exploring a potentially habitable ocean world of the outer solar system., Comment: JPL Summer School 2015

Published
2016
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10. Labyrinth terrain on Titan

Author

Malaska, Michael J., Radebaugh, Jani, Lopes, Rosaly M.C., Mitchell, Karl L., Verlander, Tiffany, Schoenfeld, Ashley M., Florence, Meghan M., Le Gall, Alice, Solomonidou, Anezina, Hayes, Alex G., Birch, Samuel P.D., Janssen, Michael A., Schurmeier, Lauren, Cornet, Thomas, Ahrens, Caitlin, and Farr, Thomas G.

Published
2020
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11. Camilla: A centaur reconnaissance and impact mission concept

Author

Howell, Samuel M., Chou, Luoth, Thompson, Michelle, Bouchard, Michael C., Cusson, Sarah, Marcus, Matthew L., Smith, Harrison B., Bhattaru, Srinivasa, Blalock, John J., Brueshaber, Shawn, Eggl, Siegfried, Jawin, Erica R., Miller, Kelly, Rizzo, Maxime, Steakley, Kathryn, Thomas, Nancy H., Trent, Kimberly R., Ugelow, Melissa, Budney, Charles J., Mitchell, Karl L., and Lowes, Leslie

Published
2018
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15. Trident: The Path to Triton on a Discovery Budget

Author

Dissley, Richard, Lam, Try, Mitchell, Karl L, Prockter, Louise, Bearden, David, and Frazier, William

Abstract

This paper describes Trident, a proposed Discovery mission to Neptune’s moon Triton, 30 AU from the Sun. Triton formed in the Kuiper Belt but was captured by Neptune into a highly-inclined retrograde orbit, where tidal forces thawed its interior, forming an ocean that likely persists to the present day. Recent outer solar system missions like Cassini and New Horizons have yielded completely new models for processes on ocean worlds, active worlds, and KBOs. Triton isn’t just a key to solar system science, it’s a whole keyring: a singular captured KBO and evolved ocean world, with active plumes, an energetic ionosphere, and a young unique surface. The NASA OPAG Roadmap to Ocean Worlds identifies Triton as the highest priority candidate ocean world [1], ripe for investigation.

Published
2020

16. Enceladus Vent Explorer Mission Architecture Trade Study

Author

Chodas, Mark, primary, Ono, Masahiro, additional, Weber, Jessica, additional, Rodriguez, Laura, additional, Ingham, Michel D., additional, Hockman, Ben, additional, Mitchell, Karl L., additional, Cable, Morgan L., additional, and Rabinovitch, Jason, additional

Published
2023
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19. Planetary Caves: A Solar System View of Processes and Products

Author

Wynne, J. Judson, primary, Mylroie, John E., additional, Titus, Timothy N., additional, Malaska, Michael J., additional, Buczkowski, Debra L., additional, Buhler, Peter B., additional, Byrne, Paul K., additional, Cushing, Glen E., additional, Davies, Ashley Gerard, additional, Frumkin, Amos, additional, Hansen‐Koharcheck, Candice, additional, Hiatt, Victoria, additional, Hofgartner, Jason D., additional, Hoogenboom, Trudi, additional, Horodyskyj, Ulyana, additional, Hughson, Kynan, additional, Kerber, Laura, additional, Landis, Margaret, additional, Leonard, Erin J., additional, Lesage, Elodie, additional, Lucchetti, Alice, additional, Massironi, Matteo, additional, Mitchell, Karl L., additional, Penasa, Luca, additional, Phillips, Cynthia B., additional, Pozzobon, Riccardo, additional, Radebaugh, Jani, additional, Sauro, Francesco, additional, Wagner, Robert V., additional, and Watters, Thomas R., additional

Published
2022
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21. PERISCOPE: PERIapsis Subsurface Cave Optical Explorer

Author

Nosanov, Jeff, Velten, Andreas, and Mitchell, Karl L

Subjects
Lunar And Planetary Science And Exploration
Abstract

The PERISCOPE study focuses primarily on lunar caves, due to the potential for being imaged in orbital scenarios. In the intervening years, from 2012-2015, scientists developed further rationales and interest in the scientific value of lunar caves. It does not appear that they are likely to be sinks for water-ice due to the relatively warm temperatures(~-20 degrees Celsius) in the caves leading to geologically-rapid migration of unbound water due to sublimation, and inevitable loss through any skylights. However, the skylights themselves reveal apparent complex layering, which may speak to a more complex multi-stage evolution of mare flood basalts than previously considered, and so their examination may provide even more insight into the lunar mare, which in turn provide a primary record of early solar system crustal formal and evolution processes. Further extrapolation of these insights can be found within the exoplanet community of researchers,who find the information useful for calibrating star formation and planetary evolution models. In addition, catalogues of lunar and martian skylights, "caves" or "atypical pit craters" have been developed, with numbers for both bodies now in the low hundreds thanks to additional high resolution surveys and revisiting the existing image databases.

Published
2019

22. Architecture of a faul-tolerant and verifiable outer planet flyby

Author

Mitchell, Karl L, Rice, Eric, and Frazier, William

Abstract

Flyby missions to outer solar system objects require a very high confidence of since there are no second chances. The quantity, quality, and diversity of science measurements to be made in a matter of hours or days must justify the mission cost. Accordingly, the mission architecture must include a high degree of redundancy, large design margins, and an ability to correct or operate through anomalies while at the same time being deterministic enough for confidence in system verification and validation. In this paper we present a system architecture as part of a proposed mission to Triton, called “Trident”.

Published
2019

28. A Reevaluation of Cryolava Flow Evolution: Assumptions, Physical Properties, and Conceptualization.

Author

Morrison, Aaron A., Whittington, Alan G., and Mitchell, Karl L.

Subjects
LAMINAR flow, TRANSITION flow, ICE on rivers, lakes, etc., LAVA flows, CHEMICAL systems, VOLCANISM
Abstract

Cryovolcanism has been invoked to explain numerous features observed on icy bodies. Many of these features show similar morphologies to volcanic features observed on Earth suggesting similar physics involved in their formation. Cryovolcanism lies at the intersection of volcanology and hydrology but as such, no one model from either discipline satisfactorily represents cryolava flow emplacement. We produced a new model for cryolava flow evolution that draws from both disciplines to track the physical, chemical, and thermal states of a hypothetical H2O‐NaCl flow on a Europa‐like body as it evolves away from the vent. This model is currently restricted to compositions on the water‐rich side of this chemical system and only predicts emplacement up to the turbulent to laminar transition. Modeling the laminar regime and a broader compositional space will be dealt with separately. Concentrations between 5 and 23 wt% (H2O‐NaCl eutectic) and initial flow thicknesses of 0.1, 1, 10, and 100 m were set as initial conditions. Model results suggest that flow may reach 40–60 vol% solids before transitioning to laminar flow. The thermal budget for these flows is dominated by the heat loss from vaporization in the low‐pressure environment. This model produces length to thickness aspect ratios, for the given compositions, that are broadly consistent with candidate cryovolcanic features on Ceres and Titan. These first‐order comparisons are not ideal and suggest the need for future modeling of cryovolcanic features in at least two dimensions. Plain Language Summary: Cryovolcanism is the icy volcanism that may occur on the surface icy bodies in the outer solar system. Erupted material will be predominantly aqueous fluid indicating that cryovolcanism lies at the intersection of volcanology and hydrology. However, neither discipline has models that adequately account for all of the parameters necessary for a cryovolcanic context. We produced a model for cryolava flow evolution that draws from both disciplines to track the physical, chemical, and thermal state of a hypothetical H2O‐NaCl flow. Results suggest that these flows may evolve more like a slush rather than a river with an expanding ice cap. These flows may also begin crystallizing while still in the turbulent regime. The transition to laminar flow may therefore be important to constrain, as it could be a point where a morphology or surface expression changes due to changing in behavior in the flow. Extending this model to different compositions and allowing more complicated mixtures may help to draw comparisons to observations of surface flows on icy satellites. Key Points: Reynolds and Stokes number suggest turbulence and particle entrainment may persist to crystal contents >60%Heat loss due to vaporization is the largest heat flux in this context, accounting for >95% of the total thermal budgetThe "life" of a cryolava flow (expressed as distance traveled) may be predominantly in the turbulent regime, whereas a silicate lava flow would be predominantly laminar [ABSTRACT FROM AUTHOR]

Published
2023
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32. Triton’s Variable Interaction With Neptune’s Magnetospheric Plasma

Author

Liuzzo, Lucas, primary, Paty, Carol, additional, Cochrane, Corey, additional, Nordheim, Tom, additional, Luspay‐Kuti, Adrienn, additional, Castillo‐Rogez, Julie, additional, Mandt, Kathleen, additional, Mitchell, Karl L., additional, Holmström, Mats, additional, Addison, Peter, additional, Simon, Sven, additional, Poppe, Andrew R., additional, Vance, Steven D., additional, and Prockter, Louise, additional

Published
2021
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34. The rheology of cryovolcanic slurries: Motivation and phenomenology of methanol-water slurries with implications for Titan

Author

Zhong, Fang, Mitchell, Karl L., Hays, Charles C., Choukroun, Mathieu, Barmatz, Martin, and Kargel, Jeffrey S.

Subjects
Landforms -- Analysis, Landforms -- Mechanical properties, Hydrology -- Analysis, Hydrology -- Mechanical properties, Volcanism -- Analysis, Volcanism -- Mechanical properties, Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2009.03.015 Byline: Fang Zhong (a), Karl L. Mitchell (a), Charles C. Hays (a), Mathieu Choukroun (a), Martin Barmatz (a), Jeffrey S. Kargel (b) Keywords: Volcanism; Saturn; Titan; Satellites; Ices; mechanical properties Abstract: The Cassini spacecraft has revealed landforms on the surface of Titan suggested to be viscous cryovolcanic flows and possibly eruptive domes. In order to relate those surface features to the processes and chemistries that produced them, it is necessary to construct flow models, which rely on characterization of the rheological properties of the eruptants. This paper describes our initial exploratory attempts to understand the rheological characteristics of cryogenic slurries, using a 40% methanol-water mixture, as a precursor to more detailed experiments. We have devised a new automated cryogenic rotational viscometer system to more fully characterize cryovolcanic slurry rheologies. A series of measurements were performed, varying first temperature, and then strain rate, which revealed development of yield stress-like behaviors, shear-rate dependence, and thixotropic behavior, even at relatively low crystal fractions, not previously reported. At fixed shear rate our data are fit well by the Andrade equation, with the activation energy modified by a solid volume fraction. At fixed temperature, depending on shearing history, a Cross model could describe our data over a wide shear rate range. A Bingham plastic model appears to be a good constitutive model for the data measured at high shear rates when the shear was global. The yield stress like behavior implies that levee formation on cryolava flows is more likely than would be inferred from the previous studies, and may provide a partial explanation for features interpreted as steep-sided volcanic constructs on Titan. Author Affiliation: (a) Ices Physical Properties Laboratory, Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA (b) Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721, USA Article History: Received 25 August 2008; Revised 5 March 2009; Accepted 8 March 2009

Published
2009

35. New estimates for Io eruption temperatures: Implications for the interior

Author

Keszthelyi, Laszlo, Jaeger, Windy, Milazzo, Moses, Radebaugh, Jani, Davies, Ashley Gerard, and Mitchell, Karl L.

Subjects
Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2007.07.008 Byline: Laszlo Keszthelyi (a), Windy Jaeger (a), Moses Milazzo (b), Jani Radebaugh (c), Ashley Gerard Davies (d), Karl L. Mitchell (d) Keywords: Io; Volcanism; Interiors Abstract: The initial interpretation of Galileo data from Jupiter's moon, Io, suggested eruption temperatures [greater than or equal to]1600[degrees]C. Tidal heating models have difficulties explaining Io's prodigious heat flow if the mantle is 1300[degrees]C, although we suggest that temperatures up to [approximately equal to]1450[degrees]C may be possible. In general, Io eruption temperatures have been overestimated because the incorrect thermal model has been applied. Much of the thermal emission from high-temperature hot spots comes from lava fountains but lava flow models were utilized. We apply a new lava fountain model to the highest reported eruption temperature, the SSI observation of the 1997 eruption at Pillan. This resets the lower temperature limit for the eruption from [approximately equal to]1600 to [approximately equal to]1340[degrees]C. Additionally, viscous heating of the magma may have increased eruption temperature by [approximately equal to]50-100[degrees]C as a result of the strong compressive stresses in the ionian lithosphere. While further work is needed, it appears that the discrepancy between observations and interior models is largely resolved. Author Affiliation: (a) Astrogeology Team, U.S. Geological Survey, 2255 N. Gemini Dr., Flagstaff, AZ 86001, USA (b) Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Dr., Tucson, AZ 85721, USA (c) Department of Geological Sciences, Brigham Young University, Provo, UT 84602, USA (d) Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA Article History: Received 30 January 2007; Revised 19 July 2007

Published
2007

36. Discovery of a flank caldera and very young glacial activity at Hecates Tholus, Mars

Author

Hauber, Ernst, van Gasselt, Stephan, Ivanov, Boris, Werner, Stephanie, Head, James W., Neukum, Gerhard, Jaumann, Ralf, Greeley, Ronald, Mitchell, Karl L., Muller, Peter, and Co-Investigator Team, The HRSC

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): Ernst Hauber (corresponding author) [1]; Stephan van Gasselt [2]; Boris Ivanov [3]; Stephanie Werner [2]; James W. Head [4]; Gerhard Neukum [2]; Ralf Jaumann [1]; Ronald Greeley [5]; Karl [...]

Published
2005
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37. Evidence from the Mars Express High Resolution Stereo Camera for a frozen sea close to Mars' equator

Author

Murray, John B., Muller, Jan-Peter, Neukum, Gerhard, Werner, Stephanie C., van Gasselt, Stephan, Hauber, Ernst, Markiewicz, Wojciech J., Head, III, James W., Foing, Bernard H., Page, David, Mitchell, Karl L., Portyankina, Ganna, and Co-Investigator Team, The HRSC

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): John B. Murray (corresponding author) [1]; Jan-Peter Muller [2]; Gerhard Neukum [3]; Stephanie C. Werner [3]; Stephan van Gasselt [3]; Ernst Hauber [4]; Wojciech J. Markiewicz [5]; James W. [...]

Published
2005
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41. Sounding Titan's Lakes and Seas: Bathymetry, Composition, and Role in the Hydrologic Cycle

Author

Hayes, Alexander, Mastrogiuseppe, Marco, Lunine, Jonathan I., Poggiali, Valerio, Lorenz, Ralph, Le Gall, Alice, Mitchell, Karl L., Department of Astronomy [Ithaca], Cornell University [New York], Universita 'La Sapienza' Roma (Istituto CNR), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), ESTER - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; One of the most surprising discoveries of the Cassini Solstice Mission is the microwave transparency of Titan's lakes and seas. Coherent processing of altimetry echoes acquired over Ligeia Mare in May 2013 revealed bottom reflections and allowed construction of a bathymetric profile as well as an estimation of the liquid loss tangent. Following the successful detection of subsurface echoes at Ligeia, the RADAR team organized a campaign to acquire altimetry over the remaining Mare. Altimetry over Kraken and Punga Maria were obtained in August 2014 and January 2015, respectively, and also show detectable subsurface echoes. Using new analysis techniques, subsurface returns were also recovered from data acquired over Ontario Lacus in 2008. The final Titan flyby (T126, April 2017) will acquire altimetry over several of the smaller lakes in Titan's north, permitting comparative studies between the Mare and lakes. In this presentation, we will report on the latest results from this ongoing campaign.Assuming a ternary composition of CH4, C2H6, and N2, the best-fit loss tangent at Ligeia Mare is consistent with 71% CH4, 12% C2H6, and 17% N2 by volume. The best-fit loss tangent Ontario Lacus is consistent with 47% CH4, 40% C2H6, and 13% N2. The higher loss tangent at Ontario Lacus could result from an increased abundance of more involatile hydrocarbons and/or nitriles; these species could be concentrated as a consequence of orbitally-driven insolation cycles that may have slowly transported volatile components (methane/ ethane) to the north over the past several tens of millennia. Initial analysis of Kraken and Punga Maria suggest liquid absorptivity similar to Ligeia Mare. In total, the bathymetric results suggest that the total volume of Titan's lakes and seas is >70,000 km3. If this liquid were evenly spread across the surface it would be equivalent to a global ocean depth of 1 m. This is equivalent to 300 times the mass of Earth's proven natural gas reserves. Unlike Earth, where the total water content in the atmosphere (1.29x104 km3) is only a fraction of the surficial reservoir (1.35x109 km3), the moisture content in Titan's atmosphere is approximately seven times larger than the volume found in its lakes and seas.

Published
2016

42. Towards an End-to-End Model Relating Microwave Observations to Bulk Chemistry of Titan’s Lakes and Seas

Author

Mitchell, Karl L., Lunine, J.I., Barmatz, Martin B., Jamieson, C. S., Malaska, Michael J., Lorenz, R. D., Mastrogiuseppe, Marco, Hayes, Alexander G., Le Gall, Alice, Soderblom, Jason M., Cardon, Catherine, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Cornell Center for Astrophysics and Planetary Science (CCAPS), Cornell University [New York], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Center for Radiophysics and Space Research [Ithaca] (CRSR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ESTER - LATMOS, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), and Massachusetts Institute of Technology (MIT)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; Constraining the bulk chemistry of Titan's lakes and seas is critical for resolving between different models of Titan's hydrological and environmental state and its evolution over time [1]. Infrared spectroscopy is able to detect the presence of some chemical species at the lake surfaces [2], but quantifying bulk adundances is limited to the top layer of the liquid because of the short optical path-length, and is complicated by obfuscating methane and haze in the atmosphere. Microwave observations overcome some of these difficulties because the seas are, in places, sufficiently transparent to allow detectable sea floor returns. Several different methods have been employed to determine microwave properties of Titan's lakes [3-6], with varying degrees of certainty and model-dependence, and to constrain the real dielectric constant and/or the loss tangent (a derivative of the complex dielectric constant). This means that, at most, two quantitative constraints can be provided for the bulk properties. In this paper, we discuss the use and potential for modeling bulk chemistry of Titan's seas. Chemical mixture modeling: Laboratory data and chemical models predict predominantly methane-ethane-nitrogen chemistry [e.g. 7,8]. However, there remains disagreement within this ternary system as to how much nitrogen should be dissolved in differing methane:ethane mixtures as a function of pressure and temperature. The chemical mixture model we implement for this study is that of Hollyday et al. [9], which is based on a Henry's Law fit to lab measurements [10]. It should be noted, however, that those efforts [10] reveal that a Henry's Law approach is insufficient, and preliminary interpretations suggest that it overestimates nitrogen solution for mixtures. By combining ongoing lab efforts [10,11] with a more complex solution model [e.g. 7] we anticipate less uncertainty. Other components of the mixture are also being considered, but these are thought to be present in sufficiently small quantities that they are less likely to impact dielectric properties with any significance. However , their presence and volumes are highly speculative , and so it's plausible that they may play an important role, especially if they exhibit extremely high loss tangents, in which case they could behave in a manner akin to squid ink in water. Dielectric modeling: If the methane-ethane-nitrogen paradigm is assumed to be true, then the die-lectric properties can be used to provide constraints on the composition within their frameworks. Our laboratory studies are an attempt to provide the critical " missing piece " : a precise model for determining the dielectric properties of these mixed compositions at appropriate temperatures. Preliminary findings [12] are that there is a unique complex dielectric constant as a function of methane:ethane ratio (which determines nitrogen fraction). Precision in dielectric constant determination is limited by the experimental procedure which results in an error of ~10-5 in loss tangent, equivalent to ~0.1 in ethane molar fraction. At present, we derive the mixture complex dielectric constant from end-member components using a Lorentz-Lorenz mixture model, which is appropriate for these non-polar molecules but remains unverified for this particular mixture. Furthermore, we have no direct measurement of dissolved nitrogen at appropriate temperatures (~90 K), and so have extrapolated based on liquid nitrogen measurements at

Published
2016

43. Nature, Distribution, and Origin of Titan’s Undifferentiated Plains ('Blandlands')

Author

Lopes, Rosaly, Malaska, Michael, Solomonidou, Anezina, Le Gall, Alice, Janssen, Michael, Neish, Catherine, Turtle, Elizabeth, Birch, Samuel, Hayes, Alexander, Radebaugh, Jani, Coustenis, Athena, Stiles, Bryan, Kirk, Randolph, Mitchell, Karl L., Lawrence, Kenneth, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Florida Institute of Technology [Melbourne], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Astronomy [Ithaca], Cornell University [New York], Department of Geological Sciences [BYU], Brigham Young University (BYU), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), California Institute of Technology (CALTECH)-NASA, and Cardon, Catherine

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; The Undifferentiated Plains on Titan are vast expanses of terrains that appear radar-dark and fairly uniform in Cassini Synthetic Aperture Radar (SAR) images and are often referred to as “blandlands”. While the interpretation of several other geologic units on Titan - such as dunes, lakes, and well-preserved impact craters - has been relatively straightforward, the origin of the Undifferentiated Plains has remained elusive. SAR images show that these terrains are mostly found at mid-latitudes and show no major topographic features. Their gradational boundaries and paucity of recognizable features make geologic interpretation challenging. We mapped the distribution of these terrains using SAR swaths up to flyby T92 (7/2013), which cover > 50% of Titan’s surface. We compared SAR images with other data sets, including topography, the response from RADAR radiometry, hyperspectral imaging data from Cassini’s Visual and Infrared Mapping Spectrometer (VIMS), and near infrared imaging from the Imaging Science Subsystem. We examined and evaluated different formation mechanisms, including (i) cryovolcanic origin, consisting of overlapping flows of low relief or (ii) sedimentary origins, resulting from fluvial/lacustrine or aeolian deposition, or accumulation of photolysis products created in the atmosphere. Our results are consistent with a sedimentary origin for the Undifferentiated Plains. We discuss the possible contributing processes (photolysis products, aeolian, and fluvial/lacustrine deposition). VIMS and radiometry analysis of the Undifferentiated Plains presented here is consistent with tholin-like materials as a major component for the materials in the Plains. We conclude that the Undifferentiated Plains are sedimentary in origin and likely formed by a combination of aeolian, fluvial and lacustrine deposition, together with atmospheric organic particle deposition, possibly in differing proportions depending on location.

Published
2015

44. Titan's Magic Island: Transient Features in a Titan Sea

Author

Hofgartner, J. D., Hayes, Alexander G., Lunine, Jonathan I., Zebker, H., Stiles, B. W., Sotin, C., Barnes, J.W., Turtle, E. P., Baines, K. H., Brown, B. H., Buratti, B. J., Clark, R. N., Encrenaz, P., Kirk, R. D., Le Gall, Alice, Lopes, Rosaly M., Lorenz, Ralph D., Malaska, Michael, Mitchell, Karl L., Nicholson, Philip, Paillou, Philippe, Radebaugh, Jani, Wall, S.D., Wood, Charles, Department of Astronomy [Ithaca], Cornell University [New York], Department of Electrical Engineering [Stanford], Stanford University, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), University of Idaho [Moscow, USA], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), University of Arizona, US Geological Survey [Denver], United States Geological Survey [Reston] (USGS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Astrogeology Science Center [Flagstaff], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ASP 2015, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Department of Geological Sciences [BYU], Brigham Young University (BYU), Planetary Science Institute [Tucson] (PSI), École normale supérieure - Paris (ENS-PSL), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Pomies, Marie-Paule

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; Titan's Magic Island/Waves, solids, or bubbles/Which can it be?/Come to this talk and see!

Published
2015

45. THEO concept mission: Testing the Habitability of Enceladus’s Ocean

Author

MacKenzie, Shannon M., primary, Caswell, Tess E., additional, Phillips-Lander, Charity M., additional, Stavros, E. Natasha, additional, Hofgartner, Jason D., additional, Sun, Vivian Z., additional, Powell, Kathryn E., additional, Steuer, Casey J., additional, O’Rourke, Joseph G., additional, Dhaliwal, Jasmeet K., additional, Leung, Cecilia W.S., additional, Petro, Elaine M., additional, Wynne, J. Judson, additional, Phan, Samson, additional, Crismani, Matteo, additional, Krishnamurthy, Akshata, additional, John, Kristen K., additional, DeBruin, Kevin, additional, Budney, Charles J., additional, and Mitchell, Karl L., additional

Published
2016
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46. Cryovolcanism on Titan: New results from Cassini RADAR and VIMS

Author

Lopes, Rosaly M. C., Kirk, Randolph L., Mitchell, Karl L., Le Gall, Alice, Barnes, Jason W., Hayes, A., Kargel, J., Wye, L., Radebaugh, J., Stofan, E. R., Janssen, M. A., Neish, Catherine D., Wall, S. D., Wood, C. A., Lunine, J.I., Malaska, M. J., Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Idaho [Moscow, USA], Department of Astronomy [Ithaca], Cornell University [New York], Department of Hydrology and Atmospheric Sciences [University of Arizona], University of Arizona, Department of Electrical Engineering [Stanford], Stanford University, Department of Geological Sciences [BYU], Brigham Young University (BYU), Proxemy Research Inc, NASA Goddard Space Flight Center (GSFC), Planetary Science Institute [Tucson] (PSI), NASA, and Department of Hydrology and Water Resources

Subjects
Volcanism, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Titan, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract

International audience; The existence of cryovolcanic features on Titan has been the subject of some controversy. Here we use observations from the Cassini RADAR, including Synthetic Aperture Radar (SAR) imaging, radiometry, and topographic data as well as compositional data from the Visible and Infrared Mapping Spectrometer (VIMS) to reexamine several putative cryovolcanic features on Titan in terms of likely processes of origin (fluvial, cryovolcanic, or other). We present evidence to support the cryovolcanic origin of features in the region formerly known as Sotra Facula, which includes the deepest pit so far found on Titan (now known as Sotra Patera), flow-like features (Mohini Fluctus), and some of the highest mountains on Titan (Doom and Erebor Montes). We interpret this region to be a cryovolcanic complex of multiple cones, craters, and flows. However, we find that some other previously supposed cryovolcanic features were likely formed by other processes. Cryovolcanism is still a possible formation mechanism for several features, including the flow-like units in Hotei Regio. We discuss implications for eruption style and composition of cryovolcanism on Titan. Our analysis shows the great value of combining data sets when interpreting Titan's geology and in particular stresses the value of RADAR stereogrammetry when combined with SAR imaging and VIMS.

Published
2013

47. Why is Enceladus' surface so radar-bright?

Author

Mitchell, Karl L., Khankhoke, U., Wall, S.D., Castillo, J.C., Janssen, M.A., Westlake, R. D., Le Gall, Alice, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Cardon, Catherine

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; The recent Cassini RADAR Enceladus E16 data reveal a tectonically-complex surface near the South Pole, including areas of different apparent backscatter characteristics. These appear to be tectonically-delimited, implying that the backscatter intensity is the result of either tectonic resurfacing or surface maturity. Previous studies using Earth-based and distant Cassini observations (Ostro et al., 2006, Icarus 183, 479-490, and references within) revealed that many icy satellites, particularly the most active, exhibit unusually low emissivity and high albedo at and near Ku-band (2.17 cm). However, the extreme nature of Enceladus' brightest surfaces are difficult to account for, and appear to be the most intensely backscattering non-specular surfaces in the solar system: up to ~6 dB sigma0 at 48-57 deg incidence angle. We have developed a 2-dimensional finite element model (Khankhoje et al., 2012, IGARSS) of Ku-band radar interactions with ice in order to explore what surface configurations could produce the observed backscatter, including large ice crystals, fracture planes and liquid films formed, under geologically plausible thermochemical conditions. Different structures and mechanisms that could produce the brightness will then be considered in the context of Enceladus' evolution, with due consideration given to whether these same factors could also apply on other icy worlds. Our preliminary results show that rough surfaces are insufficient. We speculate after Ostro et al. (2006) that these surfaces are the result of coherent backscatter from geologically immature surfaces, resulting in a phenomenon similar to cats eyes. The precise structures and their forming mechanisms (space weathering, deposition, or thermal or mechanical modification) are not yet understood, but several types of organized structure in the 10s of cms range are being considered: (1) quasi-spherical surface scatterers cobbles and small bounders, already observed at 10s of metres scales by the Imaging Science System; (2) complex but regular fractures; and (3) unusually large monocrystals. We will continue to investigate these, whittling them down by a process of deduction.

Published
2012

48. Interpreting Titan's Surface Geology from Cassini RADAR Observations

Author

Lopes, Rosaly M. C., Le Gall, Alice, Janssen, Michael A., Kirk, Randolph L., Aharonson, O., Hayes, Alex, Mitchell, Karl L., Stofan, Ellen R., Radebaugh, Jani, Wall, Stephen D., Wood, Charles A., Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), United States Geological Survey [Reston] (USGS), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Miller Institute for Basic Research in Science, University of California [Berkeley], University of California-University of California, NASA Goddard Space Flight Center (GSFC), Department of Geological Sciences [BYU], Brigham Young University (BYU), Department of Hydrology and Water Resources (HWR), University of Arizona, University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

50. Cassini evidence for acitve cryovolcanism on Saturn's moon Titan

Author

Nelson, Robert M., Kamp, Lucas W., Lopes, Rosay M.C., Matson, Dennis L., Kirk, Randolph L., Hapke, Bruce W., Boryta, Mark D., Leader, Frank E., Smythe, William D., Mitchell, Karl L., Baines, Kevin H., Jaumann, Ralf, Sotin, Christophe, Clark, Roger N., Cruikshank, Dale P., Drossart , Pierre, Lunine, Jonathan I., Combes, Michael, Bellucci, Giancarlo, Bibring, Jean-Pierre, Capaccioni, Fabrizio, Cerroni, Pricilla, Coradini, Angioletta, Formisano, Vittorio, Filacchione, Gianrico, Langevin, Yves, McCord, Thomas B., Mennella, Vito, Nicholson, Phillip D., Sicardy, Bruno, Irwin, Patrick G.J., and Pearl, John C.

Subjects
cryovolcanism, VIMS, Cassini, Titan
Published
2009

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