Results 191 to 200 of about 312,980 (227)

Temperatures within comet nuclei

Journal of Geophysical Research: Solid Earth, 1985
We have performed a theoretical study of temperatures beneath the surface of a comet's nucleus. We solve the one‐dimensional heat conduction equation for the outer portion of the comet. The upper boundary condition of the model is given by energy balance at the surface of the nucleus, including conduction of heat inward, radiation, insolation as ...
S W, Squyres, C P, McKay, R T, Reynolds
openaire   +2 more sources

Origin and Early Evolution of Comet Nuclei [PDF]

Space Sciences Series of ISSI, 2008
Foreword.- Origins of Cometary Materials.- Origin of Comet Nuclei and Dynamics.- Reservoir for Comet Material: Circumstellar Grains.- Interstellar Reservoirs of Cometary Matter.- Cometary Refractory Grains: Interstellar and Nebular Sources.- Dynamical Origin of Comets and Their Reservoirs.- Reservoirs for Comets: Compositional Differences Based on ...
exaly   +2 more sources

Disintegration of comet nuclei

Physics-Uspekhi, 2012
The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is
exaly   +2 more sources

Mid-infrared spectra of comet nuclei [PDF]

Icarus, 2017
Abridged abstract; 46 pages, 10 figures; Author's accepted manuscript with revised ...
David Harker, Charles E Woodward, William Reach   +2 more
exaly   +3 more sources

Comet nuclei and Trojan asteroids: A new link and a possible mechanism for comet splittings

Icarus, 1990
Relatively elongated shapes, implied by recent evidence of a greater incidence of high amplitude lightcurves for comet nuclei and Trojan asteroids than for similarly scaled main belt asteroids, are suggested to have evolved among comet nuclei and Trojans due to volatile loss.
William Hartmann
exaly   +2 more sources

On the visibility of nuclei of dusty comets

Icarus, 1981
Abstract The problem of visibility of a cometary nucleus discussed in general terms for single scattering by dust grains. The ratio of radiatio scattered in the dust column above the surface and that reflected from the nucleus determines the visibility of features on the nuclear surface.
R. Hellmich, H.U. Keller
openaire   +1 more source

Observational Constraints on Surface Characteristics of Comet Nuclei

Earth, Moon, and Planets, 2000
Direct observations of the nuclear surfaces of comets have been difficult; however a growing number of studies are overcoming observational challenges and yielding new information on cometary surfaces. In this review, we focus on recent determinations of the albedos, reflectances, and thermal inertias of comet nuclei. There is not much diversity in the
Humberto Campins, Yanga Fernández
openaire   +1 more source

Numerical simulation of comet nuclei I. Water-ice comets

Icarus, 1985
A one-dimensional numerical model of pure water-ice cometary nuclei is presented, and the influence of the nuclear interior as a heat reservoir on the behavior of the nuclear surface is examined. It is shown that a number of effects, including the thermal inertia due to heat stored in the core and the release of latent heat, which goes entirely into ...
G. Herman, M. Podolak
openaire   +1 more source

Rotational Behaviour of Comet Nuclei

1991
Numerical experiments of the rotational behaviour of comet nuclei have been performed, including the Sun and Jupiter’s disturbing torques in the models. In a stable configuration, the solar torque induces great librations that remain unchanged along the orbit.
P. Oberti, E. Bois, C. Froeschlé
openaire   +1 more source

Radioactive Heating of Porous Comet Nuclei

Icarus, 1995
Abstract Radioactive heating is the main energy source of comets residing in the distant parts of the Solar System. It should determine whether liquid water could have existed in comets and whether comets, presumably formed of amorphous ice, could have retained the ice, at least partly, in this pristine form.
D. Prialnik, M. Podolak
openaire   +1 more source