10 research outputs found
Obliquity of the Galilean satellites: The influence of a global internal liquid layer
The obliquity of the Galilean satellites is small but not yet observed.
Studies of cycloidal lineaments and strike-slip fault patterns on Europa
suggest that Europa's obliquity is about 1 deg, although theoretical models of
the obliquity predict the obliquity to be one order of magnitude smaller for an
entirely solid Europa. Here, we investigate the influence of a global liquid
layer on the obliquity of the Galilean satellites. Io most likely has a fully
liquid core, while Europa, Ganymede, and Callisto are thought to have an
internal global liquid water ocean beneath an external ice shell. We use a
model for the obliquity based on a Cassini state model extended to the presence
of an internal liquid layer and the internal gravitational and pressure torques
induced by the presence of this layer. We find that the obliquity of Io only
weakly depends on the different internal structure models considered, because
of the weak influence of the liquid core which is therefore almost impossible
to detect through observations of the obliquity. The obliquity of Europa is
almost constant in time and its mean value is smaller (0.033-0.044 deg) with an
ocean than without (0.055 deg). An accuracy of 0.004 deg (about 100 m on the
spin pole location at the surface) would allow detecting the internal ocean.
The obliquity of Ganymede and Callisto depends more on their interior structure
because of the possibility of resonant amplifications for some periodic terms
of the solution. Their ocean may be easily detected if, at the measuring time,
the actual internal structure model lead to a very different value of the
obliquity than in the solid case. A long-term monitoring of their shell
obliquity would be more helpful to infer information on the shell thickness.Comment: 27 pages, 6 tables, 7 figure
A factor contained in plasma is required for IGF binding protein-1 to potentiate the effect of IGF-I on smooth muscle cell DNA synthesis
SchlĂĽsselstunden im Verlauf kognitiver Verhaltenstherapie von schizophrenen Patienten: Ein Beitrag zur Prozessforschung
Behavior of nearby synchronous rotations of a Poincaré–Hough satellite at low eccentricity
International audienc
Hepatic PTEN deficiency improves muscle insulin sensitivity and decreases adiposity in mice
Behavior of nearby synchronous rotations of a Poincaré–Hough satellite at low eccentricity
Methods in Planetary Topographic Mapping: A Review
Elevation data can characterize geology, from global to local scales. For centuries, however, the only
planetary topographic data were those of lunar peaks and craters. In the last few decades, several
independent techniques have been developed to extract topographic information from diverse types of
planetary datasets, which provide key information for the distinction and geologic interpretation of surface
features. In this chapter, we discuss techniques to obtain, reconstruct, and visualize elevation data