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John J. Matese (The University of Southwestern Louisiana)
The orbital elements of new (aorig>10000AU) class I Oort cloud comets have been investigated. Evidence will be presented that there are mutual correlations between four independent orbital elements. It is found that comets with aphelia directions within an overpopulated "great circle band" have anomalously large perihelion distances as well as anomalously small semimajor axes. The fourth element is an orientation coordinate of the angular momentum vector which determines the signature of perihelion distance changes due to the galactic tidal torque, the dominant mechanism making Oort cloud comets observable during the present epoch. These statistically significant correlations are unlikely to be attributable to observational uncertainties or selection effects. The elements are associated in a way that is consistent with a model in which the Jupiter-Saturn produced loss cylinder radius is effectively reduced for comets having aphelia within the great circle band as compared to comets whose aphelia are outside the band. A potential dynamical explanation for this phenomenology is that the Solar System contains a brown dwarf of mass \approx 3MJupiter which can impart to comets in the great circle band a small impulsive angular momentum change as they recede from the planetary region. This impulse predominantly serves to smear the loss cylinder boundary inward from its nominal value of 15 AU for comets in the great circle. Thus it is easier for the galactic disk tide to further reduce the perihelion distance of small-a comets to observable values during the same orbit. A more complete discussion of this work is in press in {\em ICARUS}. The preprint can be downloaded from http://www.ucs.usl.edu/jjm9638/matese.html
This research was partially funded by the NASA-AAS Small Research Grant Program.
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The author(s) of this abstract have provided an email address for comments about the abstract: matese@usl.edu