POSSIBLE BENDING MECHANISMS OF PROTOSTELLAR JETS

Observations of several bipolar jet flows from young stellar objects r eveal a slight difference in the apparent direction of propagation for jet and counter jet. In this paper, possible mechanisms leading to su ch a jet deflection are investigated. We discuss various effects, such as the motion of the jet source within a binary system, gravitational pull due to an asymmetric external mass distribution, dynamical press ure of the external medium, inertial effects due to proper motion of t he jet source, an inclined interstellar magnetic field, and the coupli ng between a magnetic jet and an external magnetic field. We find that for typical protostellar jet parameters the most likely mechanisms le ading to a bent jet structure are Lorentz forces on the magnetic jet a nd/or motion of the jet source in a binary system. Dynamical pressure of a dense external medium or a stellar wind from a companion star can not be excluded as source of jet bending.