Showing papers in "Icarus in 1997"

TL;DR: In this article, numerical integrations of thousands of massless particles as they evolve from Neptune-encountering orbits in the Kuiper belt for up to 1 Gyr or until they either impact a massive body or are ejected from the Solar System were presented.

TL;DR: In this article, a detailed study of the production of melt and vapor in planetary impact events is carried out with hydrocode simulations, where Sandia's two-dimensional axisymmetric hydrocode CSQ was used to estimate the amount of melting and vapor produced for widely varying initial conditions: 10 to 80 km/sec for impact velocity, 0.2 to 10 km for the projectile radius.

TL;DR: In this article, the authors present results of three-dimensional simulations of the atmospheres of such planets, and comment on their possible habitability, concluding that these planets orbiting M stars can support atmospheres over a large range of conditions and, despite constraints such as stellar activity, are very likely to be habitable.

TL;DR: In this paper, the authors present results of numerical simulation of the growth of cometesimals, beginning with a uniform mixture of microscopic grains in the nebular gas, and showing that a thin, dense layer of small aggregates in the central plane of the nebula produces turbulence that initially inhibits gravitational instability.

TL;DR: Spaute et al. as mentioned in this paper used a multi-zone simulation code to model numerically the accretion of a swarm of planetesimals in the region of the terrestrial planets.

TL;DR: In this article, the authors derived the bulk chemical composition, physical properties, and trace element abundances of Mars from two assumptions: (1) Mars is the parent body for the Shergottite-Nakhlite-Chassignite (SNC) meteorites, and (2) the oxygen isotopic composition of Mars was determined by the oxygen-observable compositions of the different types of nebular material that accreted to form Mars.

TL;DR: In this article, the effects of fine particles that are approximately the same size as the wavelength of light on reflectance spectra were modeled, with the greatest few investigations of the systematic effects of the finest particles discrepancies in the restrahlen bands and the overall spectral on reflectances spectra, and on the ability of quantitative models contrast.

TL;DR: In this article, the authors used high precision spectrophotometry of 4 Vesta, the third largest asteroid, to establish the surface composition of this body and to investigate mineralogical variations across its surface.

TL;DR: In this article, the authors used a numerical code developed originally to study asteroid collisional evolution but modified to reflect collision rates in the Edgeworth-Kuiper Belt to model the evolution of the collisional process.

TL;DR: Laskar and Robutel as discussed by the authors used an energy-balance climate model to simulate Earth's climate at obliquities up to 90 degrees, and showed that Earth would become regionally severe in such circumstances, with large seasonal cycles and accompanying temperature extremes on middle and high-latitude continents which might be damaging to many forms of life.

TL;DR: Zellneret et al. as discussed by the authors investigated the spectral properties of 20 representative surface regions and found a correlation between the 1 μm absorption band depth and albedo: the units with lower albedos have shallower band depths.

TL;DR: In this article, the authors presented near-infrared laboratory spectra of pure ices of CH4, C2H4, CO, and CO2, as well as a systematic study of changes in their spectral behavior when isolated in a matrix of nitrogen ice.

TL;DR: In this article, the authors present a new mechanism for number density enhancement and size segregation of particles in a nonlaminar accretion disk, e.g., the solar nebula.

TL;DR: In this paper, the authors used HST images obtained over an interval of 71 hr at a scale of 52 km/pixel to determine the spin pole, size, and shape of Vesta.

TL;DR: In this article, the dynamical structure of the 2/3 resonance at small inclination was explored using numerical integrations of test particles to compute the evolution of proper elements with time, and the basic features are related to the analytically computed geography of secular resonances.

TL;DR: In this article, a numerical model of asteroid collisional evolution is presented, which is based on Dohnanyi's scaling law and is used to place constraints on the impact strength of asteroids.

TL;DR: In this paper, a combination of scaling laws and direct hydrocode computations that include material strength was used to show that the impact energy needed to disperse an asteroid is greater than that to thoroughly shatter it for asteroids larger than about 400 m in radius.

TL;DR: In this paper, two new Laplace-like resonances characterized by ω1/ω2≈ 3/2 and ω 1/ω 2≈ 2 can pump Ganymede's free eccentricity to ∼0.07, producing tidal heating several hundred times higher than at the present epoch and 2 to 30 times greater than that occurring in the ω(1/ϵ2)-1/2 resonance identified previously by Malhotra.

TL;DR: In this article, the authors test the hypotheses that the Moon opposition effect is due to shadow-hiding, coherent backscatter, or some combination of the two phenomena and conclude that the submicron sized grains responsible for the shadow hiding contribution behave like opaque grains, consistent with complex structure of lunar regolith particles at much larger scales than those which control the coherent back scatter contribution.

TL;DR: Wirtanen et al. as discussed by the authors showed that standing shock structures appear in the gas CNC when a sufficiently deep concave region of the surface is sunlit and even a shallow concavity gives birth to sharp dust density enhancements that, on CNC images, might look like pseudo-jet structures.

TL;DR: In this paper, the delivery dynamics of martian meteorites are examined by means of a direct numerical simulation of their orbital evolution, and it is shown that the dynamics in the martian region are dominated by secular resonant effects, not by close encounters with Mars.

TL;DR: The color of Pluto and Charon was found to be 0.873 ± 0.002 at 123° and 289° east longitude, respectively, with a peak-to-peak variation of 0.6° to 2.0° as mentioned in this paper.

TL;DR: In this paper, the authors explore the conditions under which Ganymede can undergo global thermal runaway, assuming that the Q/k of Ganyme is strongly dependent on internal temperature.

TL;DR: Rodriguez et al. as mentioned in this paper presented a 3D model of the circumnuclear coma (CNC) of a Comet P/Wirtanen (P/W).

TL;DR: In this article, the rate at which cratering events currently occur on the Moon is considered in light of their influence on the use of the Moon as a radiometric standard, and the radiometric effect of small impact events is determined empirically from the study of Clementine images.

TL;DR: In this article, the authors present spectra of Comet Hale-Bopp (C/1995 O1) covering the range 1.4-2.5 μm that were recorded when the comet was 7 AU from the Sun.

TL;DR: A simple, approximate method for the recalculation of asteroid diameters and geometric albedos given new, improved absolute visual magnitudes was presented by Tedesco et al..

TL;DR: In this paper, the authors examined previously published Earth-based telescopic spectra of Mercury with the goal of obtaining clues to the planet's surface composition and found that the mercurian spectra least affected by telluric absorptions imply FeO + TiO2≈ 4%.

TL;DR: In this article, an infrared nulling interferometer dedicated to the detection and spectroscopy of exoplanetary systems must provide very strong suppression of the light originating from the target star and good spectral coverage with a fixed baseline and must be able to distinguish planets from local dust disc emission without any ambiguity.