ACCRETION DISK RESPONSE TO A STELLAR FLY-BY

We investigate the effect on an accretion disc around one star of a parabolic fly-by of another. In the prograde, coplanar encounter, the disc is tidally stripped down to about one half of the periastron radius, and a substantial fraction of the stripped material is captured by the intruder. In the retrograde, coplanar encounter, the disc is essentially unaffected within periastron. We also consider an encounter in which the disc and orbit are initially orthogonal. Here the disc outside periastron is only partially tidally stripped, essentially no material is captured by the intruder, and the disc which remains is twisted. We comment briefly on the significance of the above results to models of binary star formation.