The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
All landforms on Titan that are unambiguously identifiable can be explained by exogenic processes (aeolian, fluvial, impact cratering, and mass wasting). Previous suggestions of endogenically produced cryovolcanic constructs and flows have, without exception, lacked conclusive diagnostic evidence. The modification of sparse recognizable impact craters (themselves exogenic) can be explained by aeolian...
We model Titan’s lakes and seas as methane–ethane–nitrogen systems and model the buoyancy of solids in these systems assuming thermodynamic equilibrium. We find that ice will float in methane-rich lakes for all temperatures below the freezing point of pure methane and that ice will also float in ethane-rich seas provided the ice has an air porosity of greater than 5% by volume.
While extratropical cyclones cannot be expected in Titan’s barotropic troposphere, tropical cyclones which gain their energy from the latent heat of sea evaporation cannot be entirely dismissed over Titan’s polar hydrocarbon seas. The most essential condition for the genesis of tropical cyclones on Titan is a methane-rich composition of the polar seas. The most likely season for Titan’s hypothetical...
Based on comprehensive mapping of the region, the recent theories of Xanadu’s origin are examined and a chronology of geologic processes is proposed. The geologic history of Titan’s Xanadu region is different from that of the other surface units on Saturn’s moon. A previously proposed origin of western Xanadu from a giant impact in the early history of the moon is difficult to confirm given the scarcity...
Although Titan’s surface shows clear evidence of erosional modification, such as fluvial incision, evidence for tectonism has been less apparent. On Earth, fluvial networks with strongly preferred orientations are often associated with structural features, such as faults or joints, that influence flow or erodibility. We delineated and classified the morphologies of fluvial drainages on Titan and discovered...
Titan, the main satellite of Saturn, has an active cycle of methane in its troposphere. Among other evidence for a mechanism of evaporation at work on the ground, dry lakebeds have been discovered. Recent Cassini infrared observations of these empty lakes have revealed a surface composition poor in water ice compared to that of the surrounding terrains—suggesting the existence of organic evaporites...
Using a new global topographic map of Titan, we find that craters on Titan preferentially lie at higher than average elevations. We explore several explanations for this observed behavior, and judge the most reasonable explanation to be the presence of widespread wetlands of liquid hydrocarbons at low elevations over much of geologic time. Impacts into a shallow marine environment or a saturated layer...
Titan’s thick atmosphere and volatile-rich surface cause it to respond to big impacts in a somewhat Earth-like manner. Here we construct a simple globally-averaged model that tracks the flow of energy through the environment in the weeks, years, and millenia after a big comet strikes Titan. The model Titan is endowed with 1.4 bars of N2 and 0.07 bars of CH4, methane lakes, a water ice crust, and enough...
The global distribution of atmospheric pressure retrieved from Cassini radio occultations is reanalyzed and interpreted in a meteorological context. The retrieval of Titan’s atmospheric pressure profile from radio occultations is ambiguous because it depends on the methane mole fraction, which is not precisely known in the troposphere beyond the entry site of the Huygens Probe. The surface pressure...
Molecular diatomic nitrogen (henceforth, “nitrogen”) is a major gas on Venus, Earth, Mars, Titan, Triton, and Pluto; a major condensed liquid component on Titan; and major condensed ices on Triton and Pluto. Nitrogen also occurs as a component of air gas hydrates in Earth’s polar ice sheets. The Solar System’s nitrogen originally might have been produced by condensation of nitrogen ice in the outer...
We present a radar map of the Titan’s seas, with bathymetry estimated as proportional to distance from the nearest shore. This naïve analytic bathymetry, scaled to a recent radar sounding of Ligeia Mare, suggests a total liquid volume of ∼32,000km 3 , at the low end of estimates made in 2008 when mapping coverage was incomplete. We note that Kraken Mare has two principal basins, separated...
Hundreds of lakes and a few seas of liquid hydrocarbons have been observed by the Cassini spacecraft to cover the polar regions of Titan. A significant fraction of these lakes or seas could possibly be interconnected with subsurface liquid reservoirs of alkanes. In this paper, we investigate the interplay that would happen between a reservoir of liquid hydrocarbons located in Titan’s subsurface and...
Several clues indicate that Titan’s atmosphere has been depleted in methane during some period of its history, possibly as recently as 0.5–1 billion years ago. It could also happen in the future. Under these conditions, the atmosphere becomes only composed of nitrogen with a range of temperature and pressure allowing liquid or solid nitrogen to condense. Here, we explore these exotic climates throughout...
We constructed a laboratory apparatus capable of measuring the saturation equilibrium concentration (c sat ) and dissolution rate constants (k eff ) of organic solutes in ethane at 94K. We determined a c sat of 18.5±1.9mg L −1 , 0.159±0.003mg L −1 , and 0.039±0.006mg L −1 for benzene, naphthalene, and biphenyl, respectively. The derived c sat ...
Simulation results are presented from a new general circulation model (GCM) of Titan, the Titan Atmospheric Model (TAM), which couples the Flexible Modeling System (FMS) spectral dynamical core to a suite of external/sub-grid-scale physics. These include a new non-gray radiative transfer module that takes advantage of recent data from Cassini–Huygens, large-scale condensation and quasi-equilibrium...
Saturn’s moon Titan, dominated by its low, 90–95K, surface temperature and methane seas, is shaped by physical and chemical processes unparalleled in any environment on Earth. Titan’s upper atmosphere produces a rain of compounds such as acetonitrile, acrylonitrile, and acetylene, more familiar to chemical processing plants than to nature. The interaction of these compounds with Titan’s seas is, to...
We analyze southern mid-latitude albedo-dark features on Titan observed by Cassini’s Visual and Infrared Mapping Spectrometer (VIMS). In exploring the nature of these features we consider their morphology, albedo, and specular reflectivity. We suggest that they represent candidates for potential temperate lakes. The presence of lakes at the mid-latitudes would indicate that surface liquid can accumulate...
Detailed analyses of slopes and arcuate planform morphologies of Titan’s equatorial mountain ridge belts are consistent with formation by contractional tectonism. However, contractional structures in ice require large stresses (4–10MPa), the sources of which are not likely to exist on Titan. Cassini spacecraft imagery reveals a methane-based hydrological cycle on Titan that likely includes movement...
In many terrestrial channels the gravel bed is only transported during rare floods (threshold channels), and rates of erosion are very slow. In this paper we explore how coarse debris delivered to channels on Mars and Titan from erosion may inhibit further erosion once a coarse gravel channel bed develops. Portions of the equatorial region of Titan are fluvially eroded into banded (crenulated) terrain,...
Density-driven circulation in Titan’s seas forced by solar heating and methane evaporation/precipitation is simulated by an ocean circulation model. If the sea is transparent to sunlight, solar heating can induce anti-clockwise gyres near the sea surface and clockwise gyres near the sea bottom. The gyres are in geostrophic balance between the radially symmetric pressure gradient force and Coriolis...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.