Angular Momentum Transfer in Star‐Disk Encounters: The Case of Low‐Mass Disks

A prerequisite for the formation of stars and planetary systems is thatangular momentum is transported in some way from the inner regions of theaccretion disc. Tidal effects may play an important part in this angularmomentum transport. Here the angular momentum transfer in an star-discencounter is investigated numerically for a variety of encounter parameters inthe case of low mass discs. Although good agreement is found with analyticalresults for the entire disc, the loss {\it inside} the disc can be up to anorder of magnitude higher than previously assumed. The differences in angularmomentum transport by secondaries on a hyperbolic, parabolic and ellipticalpath are shown, and it is found that a succession of distant encounters mightbe equally, if not more, successful in removing angular momentum than singleclose encounter.Comment: 11pages, 8 figures, 1 tabl