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We consider under what environmental conditions water waves (and thus eventually shorelines) should be expected to be produced on hypothetical ancient martian seas and lakes. For winds and atmospheric pressures that are too small, no waves should be expected, and thus no shorelines. If the winds and atmospheric pressure are above some threshold, then waves can be formed, and shorelines are possible...
Since previous long-term insolation modeling in the early 1990s, new atmospheric pressure data, increased computational power, and the upcoming flyby of the Pluto system by NASA’s New Horizons spacecraft have generated new motivation and increased capabilities for the study of Pluto’s complex long-term (million-years) insolation history. The two primary topics of interest in studying Pluto’s insolation...
Emission of volatiles for the long-period Comet C/2006 W3 Christensen was observed before perihelion from 3.7AU through perihelion passage at 3.13AU till 5.0AU after perihelion. Coma is found to be strongly enriched in molecules more volatile than water. At heliocentric distances 3.13–3.7AU activity of the comet was mostly driven by CO emission (Bockelée-Morvan, D., et al. [2010]. Astron. Astrophys...
Because of atmospheric shielding and endogenic resurfacing, the population of impact craters on Venus is small (about a thousand) and consists of large craters. This population has been used in numerous studies with the goal of deciphering the geologic and geodynamic history of Venus, but the nearly spatially random nature of the crater population has complicated efforts to understand this history...
The ∼24km Nördlinger Ries and the ∼3.8km Steinheim Basin in southern Germany are thought to represent a ∼14.8Ma old impact crater doublet. The complex craters of the Steinheim Basin with its crater fill deposits and the Nördlinger Ries and its voluminous impact ejecta blanket are still widely preserved. Although located in an environmental setting that presumably underwent the same erosional history...
We have developed a method to compute the albedo contrast between dust devil tracks and their surrounding regions on Mars. It is mainly based on Mathematical Morphology operators and uses all the points of the edges of the tracks to compute the values of the albedo contrast. It permits the extraction of more accurate and complete information, when compared to traditional point sampling, not only providing...
Despite ablation and drag processes associated with atmospheric entry of meteoroids were a subject of intensive study over the last century, little attention was devoted to interpret the observed fireball terminal height. This is a key parameter because it not only depends on the initial mass, but also on the bulk physical properties of the meteoroids and hence on their ability to ablate in the atmosphere...
Caloris basin, Mercury’s youngest large impact basin, is filled by volcanic plains that are spectrally distinct from surrounding material. Post-plains impact craters of a variety of sizes populate the basin interior, and the spectra of the material they have excavated enable the thickness of the volcanic fill to be estimated and reveal the nature of the subsurface. The thickness of the interior volcanic...
The precise mechanisms by which martian hillside gullies erode and their dependence on the local environment remain subjects of debate. We studied three sharp rimmed craters in Noachis Terra and 37 gully profiles using Context Camera (CTX), Mars Orbiter Laser Altimeter (MOLA) and High Resolution Stereo Camera (HRSC) data. We analysed the gully topographic profiles of seven gullies and nine dry ravines...
We model the transport of gas through the martian subsurface in order to quantify the timescales of release of a trace gas with a source at depth using a Fickian model of diffusion through a putative martian regolith column. The model is then applied to the case of methane to determine if diffusive transport of gas can explain previous observations of methane in the martian atmosphere.We investigate...
Recent work has suggested that gas giant planets such as Jupiter and Saturn may not consist of a small number of fully convective and chemically homogenous layers as has been conventionally assumed, but instead may be chemically inhomogeneous with convective redistribution of elements limited by semiconvection. Constructing accurate planetary models which include semiconvective processes requires...
MESSENGER orbital images show that the north polar region of Mercury contains smooth plains that occupy ~7% of the planetary surface area. Within the northern smooth plains (NSP) we identify two crater populations, those superposed on the NSP (“post-plains”) and those partially or entirely embayed (“buried”). The existence of the second of these populations is clear evidence for volcanic resurfacing...
Despite its small size, Enceladus emits considerable heat, especially at its south pole, even long after simple thermal models predict it should be frozen. Several sources of energy have been proposed as responsible for this heating, such as tidal dissipative heating (TDH), convection and shearing in the ice shell, and exothermic chemical reactions (e.g., serpentine formation). Crater relaxation simulations...
We combine Earth-based radar maps of Venus from the 1988 and 2012 inferior conjunctions, which had similar viewing geometries. Processing of both datasets with better image focusing and co-registration techniques, and summing over multiple looks, yields maps with 1–2km spatial resolution and improved signal to noise ratio, especially in the weaker same-sense circular (SC) polarization. The SC maps...
During a survey of the S-type asteroids, Gaffey et al. (Gaffey, M.J., Bell, J.F., Brown, R.H., Burbine, T.H., Piatek, J., Reed, K.L., Chaky, D.A. [1993]. Icarus 106, 573–602) identified Asteroid (354) Eleonora as anomalous with a 1μm absorption feature ∼2.5 times stronger than any S-asteroid of comparable size. Subsequent investigation revealed significant differences in the 1μm absorption feature...
We analyzed spectra acquired at the limb of Titan in the 2006–2013 period by the Cassini/Composite Infrared Spectrometer (CIRS) in order to monitor the seasonal evolution of the thermal, gas composition and aerosol spatial distributions. We are primarily interested here in the seasonal changes after the northern spring equinox and interpret our results in term of global circulation seasonal changes...
We have developed a new retrieval approach to modelling near-infrared spectra of Uranus that represents a significant improvement over previous modelling methods. We reanalysed IRTF/SpeX observations of Uranus observed in 2009 covering the wavelength range 0.8–1.8μm and reported by Tice et al. (Tice, D.S., Irwin, P.G.J., Fletcher, L.N., Teanby, N.A., Hurley, J., Orton, G.S., Davis, G.R. [2013]. Icarus...
We present morphologic observations and spectral modeling results of a large, kaolin-group mineral-bearing deposit within Kashira crater in the southern highlands of Mars. We employ both non-linear unmixing of Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) visible to near-infrared (VNIR) reflectance data and linear unmixing of Thermal Emission Spectrometer (TES) thermal infrared (TIR)...
High-resolution mapping by visible and near-infrared orbital spectrometers has revealed a diversity of hydrated mineral deposits on the surface of Mars. Quantitative analysis of mineral abundances within these deposits has the potential to distinguish depositional and diagenetic processes. Such analysis can also provide important constraints on the nature of putative global and local-scale mineralogical...
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