DPS Pasadena Meeting 2000, 23-27 October 2000
Session 37. Comets Posters - Orbital Dynamics, Nuclei
Displayed, 1:00pm, Monday - 1:00pm, Friday, Highlighted Tuesday and Thursday, 3:30-6:30pm, C101-C105, C211

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[37.02] Characteristics of a Weak Stellar Shower of Oort Cloud Comets

J. J. Matese (University of Louisiana), J. J. Lissauer (NASA ARC)

We have developed a model of the tidal perturbations of the adiabatic galactic force and a stellar impulse acting on the Sun and outer Oort cloud of comets. The six dimensional phase space of near-parabolic comet orbital elements has been subdivided into 5\times106 cells. A mapping of the evolution of these elements from beyond the loss cylinder boundary into the inner planetary region over the course of a single orbit is possible. This is done treating each perturbation separately, and in combination, during a time interval of 5 My. The time dependence of a wide range of comet flux characteristics is then obtained. These include the flux distributions of energy, perihelion distance, major axis orientation and angular momentum orientation. Correlations between these variables are also determined. We show that substantive errors occur if one superposes the separately obtained flux results of the galactic tide and the stellar impulse rather than superposing the tidal and impulsive perturbations into a single analysis. Detailed illustrations will be given for an example case where the stellar mass and relative velocity have the ratio M\star/Vrel = 0.02 \rm{M\sun(km/s)-1} and the solar impact parameter is 60000 AU. In this case the peak in the observable comet flux exceeds the steady state value due to the galactic tide alone by 25%, while the superposition of separately obtained flux results gives a peak increase only half as large. Further, the latter case significantly underestimates the increase at early shower stages and overestimates it at later stages. This occurs because the stellar impulse alone underestimates the increase in small-a early arriving comets and similarly overestimates the increase in large-a late arriving comets. \newline \em{JJM acknowledges the support of a NSF-AAS Small Research Grant and a NASA-ASEE Summer Faculty Fellowship at Ames Research Center.}

If you would like more information about this abstract, please follow the link to http://www.ucs.louisiana.edu/~jjm9638/matese.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: matese@louisiana.edu

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