Results 181 to 190 of about 7,027 (228)

Dynamics of the AMPTE artificial comet

Nature, 1986
Sweeping the plasma before it, the interplanetary magnetic field quickly penetrated into an initially diamagnetic barium plasma cloud. The field was strongly compressed and extended in the flow direction. Ions accelerated by electric polarization fields formed a visible tail at the rear of the cloud; their recoil balancing the magnetic stresses.
G. Haerendel, G. Paschmann, W. Baumjohann, C. W. Carlson   +3 more
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Dynamical Relation of Meteorids to Comets and Asteroids

Earth, Moon, and Planets, 2004
We tested four criteria used for discrimination between asteroidal and cometary type of orbits: Whipple criterion K, Kresak criterion Pe, Tisserand invariant T and aphelion distance Q. To estimate their reliability, all criteria were applied to classify the 2225 orbits of NEAs and 582 orbits of comets, for several epochs spanning the time interval of ...
S. Starczewski, T. J. Jopek
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Dynamics of periodic comets and meteor streams

Celestial Mechanics and Dynamical Astronomy, 1992
The methods for an investigation of the evolution of orbits with large eccentricities are presented. The role of resonances in the motion of comets is considered. The expansion of the disturbing function in the restricted three-body problem is obtained for cometary orbits. The method is based on the proximity of cometary eccentricities to 1.
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Rapid dynamical evolution of giant comet Chiron

Nature, 1990
Numerical simulation of orbits like that of the giant comet Chiron show a distinct asymmetry between past and future. Simulations extending ±100,000 years from the present suggest that on this time-scale, Chiron is about twice as likely to have been a short-period comet at some time in the past as to become one in the future.
G. Hahn, M. E. Bailey
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Origin of Comet Nuclei and Dynamics

Space Science Reviews, 2007
We present a review of the main physical features of comet nuclei, their birthplaces and the dynamical processes that allow some of them to reach the Sun’s neighborhood and become potentially detectable. Comets are thought to be the most primitive bodies of the solar system although some processing—for instance, melting water ice in their interiors and
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Dynamically New Comets in the Solar System

2001
Traditional definition of a dynamically ‘new’ comet, which is the comet for the first time visiting our planetary system, is that it should have its 1/a < 1 × 10−4 AU−1 (eg. Oort and Schmidt, 1951). This definition is based on the value of semimajor axis of the comet at the moment it is observed, but it does not take into regard its dynamical history ...
Piotr A. Dybczyński, Halina Prfętka-Ziomek   +1 more
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Dynamical Evolution and Disintegration of Comets

1982
Current concepts of the origin and evolution of comets are reviewed. The place of their formation from which they have been delivered into the Oort reservoir is still an open problem, but the region of the outermost planets appears most probable. The interplay of stellar and planetary perturbations can be traced by model computations which reveal both ...
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Dynamical Features of the Oort Cloud Comets

2009
The Oort cloud which corresponds to the outer boundary of our Solar system, is considered to be the main reservoir of long period comets. At such distance from the Sun (several times 10 000 AU), the comet trajectories are affected by the galactical environment of the Solar System.
M. Fouchard, C. Froeschlé, H. Rickman, G. B. Valsecchi   +3 more
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Dynamical Origin of Comets and Their Reservoirs

Space Science Reviews, 2008
It is widely believed that cometary orbits contain important clues to both the outer solar system’s current structure and its past dynamical evolution. The first part of this paper summarizes the results of numerical simulations designed to study the dynamical origins of observed comets and to link the observed populations to the reservoirs from which ...
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Origin and dynamics of comets and star formation

Planetary and Space Science, 1997
Abstract Several important consequences that would arise for the solar system's comet population if the Sun formed in an embedded star cluster are outlined. Owing to the higher stellar number density and larger tidal fields in this environment, formation of the comet cloud would proceed differently from that envisaged in a usually assumed isolated ...
Eggers, S., Keller, H., Kroupa, P., Markiewicz, W.   +3 more
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