Showing papers in "Icarus in 1999"

TL;DR: In this article, the authors used a smooth particle hydrodynamics method to simulate colliding rocky and icy bodies from centimeter scale to hundreds of kilometers in diameter in an effort to define self-consistently the threshold for catastrophic disruption.

TL;DR: In this paper, a model was proposed to assess the thermal stability of polar ice deposits on the surface of either body by calculating temperatures of flat surfaces and surfaces within bowl-shaped and flat-floored polar impact craters on Mercury and the Moon.

TL;DR: In this paper, a simple one-dimensional geometrical-optics model for spectral albedo of powdered surfaces, in particular of lunar regolith, has been presented.

TL;DR: In this paper, the authors performed three-dimensional N-body integrations of the final stages of terrestrial planet formation and determined the spin angular momentum states of the growing planets by summing the contributions from each collisional encounter, with an emphasis on the type of impact which is believed to have triggered the formation of Earth's Moon.

TL;DR: Paleolakes in impact craters on Mars were characterized at global scale using the Viking Orbiter data as discussed by the authors, and 179 paleolakes were identified in impact structures formed by the influx of water and sediment derived from valley networks and channels that can be classified into three different fluviolacustrine systems: closed, open and lake-chain systems.

TL;DR: In this paper, the integrated spectral absorbances (ISA) for HCOOH and HCO trapped in H2O ice were measured for the first time, along with published A's for H2CO and CH3OH, were used to calculate radiation yields and conventional percentage yields.

TL;DR: The Megallan Doppler radiometric tracking data provides unprecedented precision for spacecraft based gravity measurements with the maximum resolution approaching spherical harmonic degree and order 180 in selected equatorial regions as discussed by the authors.

TL;DR: It is found that the observed stratospheric hazes do not warm this region appreciably and that any postulated hazes capable of warming the stratosphere sufficiently are inconsistent with Voyager and ground-based constraints.

TL;DR: In this paper, the analysis of near-infrared observations of the icy surface of Triton, recorded on 1995 September 7, with the cooled grating spectrometer CGS4 at the United Kingdom Infrared Telescope (Mauna Kea, HI), was performed in two steps.

TL;DR: In this paper, a scaling model based on the concept that fragmentation is accomplished through the growth and coalescence of preexisting flaws is used to validate the model, which is believed to apply to the shattering of a wide range of rock types.

TL;DR: Using a dual-layered crustal thickness model of the Moon, the excavation cavities of some nearside multiring basins (Grimaldi and larger, and younger than Tranquillitatis) were reconstructed by restoring the uplifted Moho to its preimpact location as mentioned in this paper.

TL;DR: In this article, the authors show that at least 18% of the surface of Europa is fresh appearing chaos, an additional 4% is slightly modified chaos, and much more older chaotic terrain has been overprinted by tectonic structures.

TL;DR: In this article, an analysis of Clementine data obtained from a UVVIS camera and simulating laboratory photometric and polarimetric measurements is presented with the use of a new photometric three-parameter function combining the shadow-hiding and coherent backscatter mechanisms.

TL;DR: In this article, a systematic exploration of the chaotic structure of the asteroid belt is presented, first taking into account only the perturbations provided by the four giant planets and then including also the effects of the inner planets.

TL;DR: In this article, the authors study the evolution of long-period comets by numerical integration of their orbits, a more realistic dynamical approach than the Monte Carlo and analytic methods previously used to study this problem.

TL;DR: In this article, a simplified analytical model of an evolutionary nebula is used to generate temperature-density radial profiles following the procedure elaborated by Dubrulle (Icarus106, 59, 1993).

TL;DR: In this article, the authors investigated the growth rate of a migrating protoplanet accreting planetesimals in the solar nebula and derived the criterion of the migration speed for the shepherding of planetsimals through numerical simulations and an analytical estimate.

TL;DR: In this paper, the Galileo Solid State Imager (SSI) detected lightning from 26 storms on the night side of Jupiter and used these widths to infer the depth of the strikes, assuming that the appearance of each is the result of light scattering from a point source below the cloudtops.

TL;DR: In this paper, the authors investigate this regime for internally heated convection with temperature and pressure-dependent power-law viscosity (dislocation creep) and obtain scaling relationships for large aspect ratio convection.

TL;DR: In this article, the authors studied the dynamics of the three-body problem when two objects are in the 1:1 mean motion commensurability and can experience close encounters, and three orbit families are relevant to the dynamics: horseshoe orbits, passing orbits, and retrograde satellite orbits.

TL;DR: In this paper, the authors suggest that the failures of the previous models were due to the fact that geometric effects were not taken into account, and they find that steep size distributions are necessarily produced by fragmentations of the parent bodies.

TL;DR: In this paper, the authors present new 1.20 to 2.35 μm spectra of satellites of Jupiter, Saturn, and Uranus, and the rings of Saturn, obtained in 1995 and 1998 at Lowell Observatory.

TL;DR: In this paper, the authors investigated the Brownian stage of dust growth in the cold part of a protoplanetary disc around a young stellar object and found that the friction time of the grains scales with the fifth root of the particle radius although the average fractal dimension of the growing grains is smaller than two.

TL;DR: Yeomans et al. as discussed by the authors analyzed the surface morphology of Mathilde and found that it is dominated by large craters, at least four of which have diameters comparable to Mathilde.

TL;DR: In this paper, the authors present results from observations by the Near-Infrared Mapping Spectrometer (NIM) for the first ten orbits of the Galileo spacecraft, correlate them with results from the Solid State Imaging System (SSI) and from ground-based observations, and compare them to what was known about Io's volcanic activity from observations made during the two Voyager fly-bys in 1979.

TL;DR: In this paper, the authors applied computer stereophotogrammetry to Apollo Lunar Surface Closeup Camera (ALSCC) pictures of the lunar surface to construct the first-ever digital topographic relief maps of undisturbed lunar soil over spatial scales from 85 μm to 8.5 cm.

TL;DR: Basilevsky et al. as mentioned in this paper proposed that the plains have been built up by lavas erupted in a number of different styles, each occurring throughout the history represented by the exposed stratigraphy of the planet.

TL;DR: The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on the icy Galilean satellites of Jupiter as discussed by the authors, of which Callisto exhibits discrete mass movements that are larger and apparently more common than seen elsewhere.

TL;DR: In this paper, the authors studied the dynamical excitation that large planetesimals, scattered either by Neptune or Jupiter, could have provided to the primordial Edgeworth-Kuiper belt and the asteroid belt.

TL;DR: In this article, a multispectral photometric study of the Moon between solar phase angles of 0 and 85° was performed using the Clementine UV/Vis camera and a correction factor of 0.532 was determined to convert the web site (www.planetary.brown.edu/clementine/calibration.html) reflectances to absolute values.