Search Publications
Modeling microwave backscatter and thermal emission from linear dune fields: Application to Titan
Lorenz, R. D.; Janssen, M. A.; Kirk, R. L. +1 more
We present an electromagnetic model that relates the microwave backscatter and thermal emission from linear dune fields to their compositional, physical (roughness, subsurface porosity/heterogeneity) and geometrical (slope, orientation) properties. This model shows the value of exploring these highly directional and geometrical features in light o…
An estimate of the dust pickup current at Enceladus
Gurnett, D. A.; Kurth, W. S.; Wahlund, J. -E. +3 more
We demonstrate that the acceleration of submicron dust originating at Enceladus by a reduced co-rotating E-field is capable of creating a dust pickup current perpendicular to the magnetic field with values ranging from 3 to 15 kA (depending upon the effective grain charge). Such a current represents a new contribution to the total pickup current i…
Quantitative analysis of the morphology of martian gullies and insights into their formation
Yue, Z.; Hu, W.; Liu, B. +4 more
The process of formation of observed geologically recent gully features on Mars has remained a topic of intense debate since their discovery. In this study, we performed quantitative morphological analysis on certain parameters of gullies from different settings, such as crater walls, terraces, and sand dunes, on the martian surface in addition to…
First observations of the Phoebe ring in optical light
Hedman, Matthew M.; Burns, Joseph A.; Tamayo, Daniel
The Phoebe ring, Saturn’s largest and faintest ring, lies far beyond the planet’s well-known main rings. It is primarily sourced by collisions with Saturn’s largest irregular satellite Phoebe, perhaps through stochastic macroscopic collisions, or through more steady micrometeoroid bombardment. The ring was discovered with the Spitzer Space Telesco…
Non-uniform global methane distribution in Titan’s troposphere evidenced by Cassini radio occultations
Tokano, Tetsuya
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 e…
Mid-infrared spectroscopy of components in chondrites: Search for processed materials in young Solar Systems and comets
Lisse, C. M.; Grady, M. M.; Morlok, A. +2 more
We obtained mid-infrared spectra of chondrules, matrix, CAIs and bulk material from primitive type 1-4 chondrites in order to compare them with the dust material in young, forming Solar Systems and around comets. Our aim is to investigate whether there are similarities between the first processed materials in our early Solar System and protoplanet…
Properties of a large-scale flux rope and current sheet region on the dayside of Mars: MGS MAG/ER and MEX ASPERA-3 ELS observations
Barabash, Stas; Coates, Andrew J.; Frahm, Rudy A. +6 more
We present dual spacecraft observations by MGS MAG/ER and MEX ASPERA-3 ELS of a large-scale magnetic flux rope on the dayside of Mars that occurs in close proximity to the crustal magnetic fields and a dayside current sheet region. A current sheet (including the large-scale flux rope) was observed on repeated MGS orbits when the draped solar wind …
Searching for springtime zonal liquid interfacial water on Mars
Kereszturi, Akos; Appéré, Thomas
We analyzed the spatial and temporal characteristics of the surface temperature at the northern water ice annulus on Mars that is left behind the receding seasonal carbon dioxide cap in springtime. Using OMEGA hyperspectral images we show that water ice without carbon dioxide ice coverage lasts for 10-30 days between 55° and 70°N. The longest wate…
The orbit of transneptunian binary Manwë and Thorondor and their upcoming mutual events
Grundy, W. M.; Noll, K. S.; Benecchi, S. D. +1 more
A new Hubble Space Telescope observation of the 7:4 resonant transneptunian binary system (385446) Manwë has shown that, of two previously reported solutions for the orbit of its satellite Thorondor, the prograde one is correct. The orbit has a period of 110.18 ± 0.02 days, semimajor axis of 6670 ± 40 km, and an eccentricity of 0.563 ± 0.007. It w…
Analysis of clumps in Saturn's F ring from Voyager and Cassini
Showalter, Mark R.; French, Robert S.; Hicks, Shannon K. +2 more
Saturn's F ring is subject to dynamic structural changes over short periods. Among the observed phenomena are diffuse extended bright clumps (ECs) ∼3-40° in longitudinal extent. These ECs appear, evolve, and disappear over a span of days to months. ECs have been seen by the two Voyager spacecraft, the Cassini Orbiter, and various ground- and space…