[6.11] The Scattered Disk as a Source of Halley-Type Comets

35th Meeting of the AAS Division on Dynamical Astronomy, April 2004
Session 6 Asteroids \& TNOs
Oral, Thursday, April 22, 2004, 2:15-6:50pm,

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[6.11] The Scattered Disk as a Source of Halley-Type Comets

H.F. Levison (SwRI), M.J. Duncan (Queen's U), L Dones (SwRI)

We will describe a new dynamical mechanism for producing Halley-type comets from the scattered disk of comets. Levison & Duncan~(1997) and Duncan & Levison~(1997) showed that a significant number of objects leave the scattered disk by evolving to semi-major axes greater than 1000\,AU. We find that once these objects reach semi-major axes on the order of 10⁴\,AU, a significant fraction immediately have their perihelia driven inward by the Galactic tides. Approximately 0.01% of these objects evolve onto orbits similar to the observed Halley-like comets due to gravitational interactions with the giant planets. The orbital element distribution resulting from this process is statistically consistent with observations. In order for the scattered disk to supply all the known HTCs, it must contain roughly 5 billion comet-sized objects.

This research was supported by NASA's Origins and PGG programs.

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