Sun-grazing comets and tidal disruption.
Data interpretation for sun grazing family of comets deriving formulas for compressive and tensile stress in spherical bodies for tidal, rotational and self-gravitating fields
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Data interpretation for sun grazing family of comets deriving formulas for compressive and tensile stress in spherical bodies for tidal, rotational and self-gravitating fields
Cometary dust studied by analysis of scattered sunlight in heads and tails of comets
Comet mission study using space probes boosted by Atlas Agena and Atlas Centaur launch vehicles for interception from 1967 to 1975
The NASA Discovery STARDUST Mission will fly by comet P/Wild 2 in January 2004 and return cometary dust particles to earth in January 2006.
In situ analysis of a cometary nucleus and return of a sample are high priority scientific goals. Rendezvous and sample return trajectories to comets using low-thrust ion propulsion are presented.
The temporal distribution of the Kreutz group of sungrazing comets has been known to have an episodic character on timescales from weeks to tens of years.
Extensive observations of comet Hale-Bopp from the ground and space have considerably expanded our knowledge of cometary dust.
Odyssey is an exciting comet nucleus orbiter mission submitted to the Discovery 2000 Annoucement of Opportunity.
Comets occasionally give a dazzling light displays in the night sky, but they may also help us to understand the chemical processes that led to our existence on Earth.
Target Selection: emphasis on diversity and unique objects. Flybys of three comets.
Silicates in comets appear to be a mix of high-temperature crystalline enstatite and forsterite plus glassy or amorphous grains that formed at lower temperatures.
Using the available observations in 1699, 1865-66, and 1965, and orbit has been re-computed for periodic comet 55P/Tempel-Tuttle, the parent body of the Leonid Meteors.
Covers observations and nuclear splitting of comet 73P/Schwassmann-Wachmann 3. Gives evidence in the data which argues against models of strengthless cometary nucleus.
Surface water ice on a comet nucleus is the major source of coma gas. Dust, entrained by coma gas, fragments and vaporizes, forming a second, distributed source of coma gas constituents. Ice species more volatile than water ice below the surface of the nucleus are a third source of coma gas. Vapors from these ices, produced by heat penetrating into the nucleus, diffuse through pores outward into the coma. The second and third sources provide minor, but sometimes easily detectible, gaseous species in the coma. We present mixing ratios of observed minor coma constituents relative to water vapor as a function of heliocentric and cometocentric distances and compare these ratios with model predictions, assuming the sources of the minor species are either coma dust or volatile ices in the nucleus.
An attempt to detect Doppler effects on Jupiter during the impact of fragment A of the Shoemaker-Levy 9 comet is discussed. A short description is given of the technique used to observe the impact. Observations are presented, and a theoretical analysis and inter- pretation are given. The instrumentation used is an advanced and more sensitive version of the Magneto-Optical Filter & a 40 cm telescope.
The impacts of fragments K and R of comet Shoemaker-Levy 9 are examined with the aim to interpret the timing of the observed precursors to the main thermal emission event and to correlate the results of ground-based infrared observations with a variety of observations made onboard the Galileo spacecraft. Independent observations of the impact phenomena (of K & R) are combined.
The results of observations of Jupiter's synchrotron radiation during the period surrounding the impacts of comet SL-9 are reported. The observations were made at the Naval Research Laboratory's Maryland Point Observatory 85 foot radio antenna operating at 1665 MHz (18 cm). The data indicate that an increase in the intensity of the synchrotron emission of 23% took place over the full duration of the impact period. The increase was accompanied by two characteristic changes in the beaming curve: a flattening and the creation of brightness temperature variations on hourly timescales. We interpret the latter as longitudinal variations in the beaming curve which suggests a localized mechanism resulting in a redistribution of the radiating electronis in the Jovian radiation belts.
Changes to Jupiter's synchrotron radiation following the impact of Comet Shoemaker-Levy/9 are reported. Also, the consequences are reported for three possible mechanisms that might have caused those changes.