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Akaganeite has been found in Yellowknife Bay mudstones of the Gale crater by the Chemistry and Mineralogy X-ray diffraction instrument (CheMin) aboard the Curiosity rover. This phase has also been discovered in limited locations on Mars by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter. Akaganeite has also been proposed as a precursor candidate...
Impact craters across Mars, that are otherwise similar, commonly exhibit vastly different thermal inertia values on their rims. We focused on the Tisia Valles region because the terrain is mostly flat, and craters of various ages are present within the same target geologic unit. We present an investigation of two hypotheses for why these thermal inertia variations exist. The first hypothesis is that...
Pluto's atmospheric haze settles out rapidly compared with geological timescales. It needs to be accounted for as a surface material, distinct from Pluto's icy bedrock and from the volatile ices that migrate via sublimation and condensation on seasonal timescales. This paper explores how a steady supply of atmospheric haze might affect three distinct provinces on Pluto. We pose the question of why...
The Surface Electrical Properties (SEP) experiment deployed at the Apollo 17 landing site in the Taurus-Littrow valley was a continuous-wave, radiofrequency (1–32 MHz) interferometer designed to probe the subsurface from depths of meters to kilometers. Signals were transmitted by orthogonal electric dipoles laid out near the lunar module and three components of the magnetic field were measured on...
In this investigation, HiRISE images were surveyed across three regions of the Northern Plains of Mars; Acidalia, Arcadia and Utopia Planitiae. A sample of HiRISE images within each of these areas was examined. The aim of the investigation was to determine the distribution of three varieties of landform; clastic patterned ground, lobate hill-slope features and scalloped depressions. These features...
The Mars South Polar Layered Deposits (SPLD) are the result of depositional and erosional events, which are marked by different stratigraphic sequences and erosional surfaces. To unambiguously define the stratigraphic units at regional scale, we mapped the SPLD on the basis of observed discontinuities (i.e., unconformities, correlative discontinuities and conformities), as commonly done in terrestrial...
Polygonal networks of patterned ground are a common feature in cold-climate environments. They can form through the thermal contraction of ice-cemented sediment (i.e. formed from fractures), or the freezing and thawing of ground ice (i.e. formed by patterns of clasts, or ground deformation). The characteristics of these landforms provide information about environmental conditions. Analogous polygonal...
Changes in Martian fluvial geomorphology with time-stratigraphic age, including decreases in paleochannel widths, suggest waning paleodischarges through time. Where fluvial landforms do not preserve paleochannel widths (e.g., meander deposits), other landform dimensions (i.e., radius of curvature) may be used to estimate paleodischarges. In the Aeolis Dorsa region, topographically inverted and stacked...
Solid CO2 surface deposits were reported in Enceladus’ South Polar Region by Brown et al. (2006). They noted that such volatile deposits are temporary and posited ongoing replenishment. We present a model for this replenishment by expanding on the Matson et al. (2012) model of subsurface heat and chemical transport in Enceladus. Our model explains the distributions of both CO2 frost and complexed...
Recurring slope lineae (RSL) are narrow dark features that incrementally lengthen down steep low-albedo slopes when temperatures are warm, subsequently fade, and reoccur annually. RSL could be caused by wet, wet-triggered debris, or dry granular flow mechanisms. We have classified 190 candidate and confirmed southern mid-latitude (SML) RSL sites using six Mars years of high-resolution imagery to provide...
Bladed Terrain on Pluto consists of deposits of massive CH4, which are observed to occur within latitudes 30° of the equator and are found almost exclusively at the highest elevations (> 2 km above the mean radius). Our analysis indicates that these deposits of CH4 preferentially precipitate at low latitudes where net annual solar energy input is lowest. CH4 and N2 will both precipitate at low...
We identified and mapped 129 mare basalt deposits in and around the South Pole–Aitken (SPA) basin, and determined absolute model ages (AMAs) for 101 of these units by performing crater size-frequency distribution (CSFD) measurements. The derived AMAs range from 2.2 Ga to 3.7 Ga, with the youngest deposits within Antoniadi crater and the oldest deposits at Jules Verne crater. Our investigations indicate...
We determine the depth of fracture penetration in multiple regions of Enceladus by performing self-similar clustering and length distribution analysis of fractures. The statistical characterization of fault-population attribute, such as length and clustering, provide a productive avenue for exploring deformation rate, stress transmission mode, rheology of the medium, and mechanical stratification...
As the youngest features on Ganymede, ray craters are useful in revealing the sources of recent impactors and surface modification processes on the satellite. We examine craters with D> 10km on Ganymede from images obtained by the Voyager and Galileo spacecraft to identify ray craters and study their spatial distributions. Furthermore, we carefully select images of appropriate solar and emission...
This work investigates the macroscopic thermomechanical behavior of lunar boulders by modeling their response to diurnal thermal forcing. Our results reveal a bimodal, spatiotemporally-complex stress response. During sunrise, stresses occur in the boulders’ interiors that are associated with large-scale temperature gradients developed due to overnight cooling. During sunset, stresses occur at the...
As the target of the proposed Asteroid Impact & Deflection Assessment (AIDA) mission, the near-Earth binary asteroid 65803 Didymos represents a special class of binary asteroids, those whose primaries are at risk of rotational disruption. To gain a better understanding of these binary systems and to support the AIDA mission, this paper investigates the creep stability of the Didymos primary by...
Solar system small bodies come in a wide variety of shapes and sizes, which are achieved following very individual evolutional paths through billions of years. Nevertheless, some common mechanisms can still be found during these processes, e.g., rubble-pile asteroids tend towards fluid equilibrium as they are reshaped by external disturbances. This paper focuses on the reshaping process of rubble-pile...
The highlands region north and east of Sputnik Planitia can be subdivided into seven terrain types based on their physiographic expression. The northern rough uplands are characterized by jagged uplands and broad troughs, and it may contain a deeply-eroded ancient mantle. Dissected terrain has been interpreted to have been eroded by paleo-glaciation. The smooth uplands and pits terrain contains broad,...
Surface roughness is a key property of soils that controls many surface processes and influences the scattering of incident electromagnetic waves at a wide range of scales. Hapke (2012b) designed a photometric model providing an approximate analytical solution of the Bidirectional Reflectance Distribution Function (BRDF) of a particulate medium: he introduced the effect of surface roughness as a correction...
We obtained laboratory measurements of nitrogen solubility in mixed solutions of ethane and methane at temperatures and pressures relevant to Titan's lakes and seas. Our results show that nitrogen solubility is increased at higher methane concentration, lower temperature, and higher pressure. We developed an empirical fit that agrees well with our measurements. We show that significant volumes of...
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