DPS 2001 meeting, November 2001
Session 31. Cometary Nuclei and Dynamics
Oral, Chairs: D. Scheeres, C. Lisse, Thursday, November 29, 2001, 2:40-4:20pm, Regency E

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[31.06] Frequency of Weak Stellar Showers of Oort Cloud Comets

J. J. Matese (University of Louisana and NASA ARC), J. J. Lissauer (NASA ARC)

We have developed a semi-analytic model of the combined effects of tidal perturbations of the galactic force and a stellar impulse acting on the Sun and the outer Oort cloud of comets. The six dimensional phase space of near-parabolic comet orbital elements has been subdivided into 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. The time dependence of the comet flux interior to 5 AU is then obtained for a period of 5 Myr subsequent to the impulse. The peak flux and the time integrated net shower flux are obtained over a wide range of stellar impact parameters bsolar > 30 000 AU and stellar mass to relative velocity ratios, M*/Vrel, such that the peak flux enhancement is <1.5 times the background flux due to the galactic tide alone. Loci of the results for the peak flux enhancement and the time integrated net shower flux versus bsolar and M*/Vrel are given. Using the number densities and dispersion velocities of stellar populations we also obtain the time dependent probability of a stellar impulse versus bsolar and M*/Vrel. Finally, we employ Monte Carlo sampling to estimate the frequency of stellar encounters as functions of the peak flux enhancement and also of the time integrated net shower flux. A graph of the cumulative number of stellar impulses expected over 4 Gyr as a function of the shower strength will also be given.

\em{JJM acknowledges the support of a NASA-AAS Small Research Grant and a NASA-ASEE Summer Faculty Fellowship at Ames Research Center. JJL received support from Planetary Geology and geophysics grant 334-30-50-01}

If you would like more information about this abstract, please follow the link to http://www.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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