ENTRAINMENT BY THE JET IN HH-47

Fabry-Perot images of the HH 47 optical jet show that the velocity dec reases from the center toward the edges which is interpreted as eviden ce for entrainment. Those images can be used to investigate the rate o f entrainment required to account for the observed luminosity. Entrain ment along the jet can account for only small fractions of the jet mas s and the molecular outflow seen in CO. We compare the density, excita tion, and velocity structure of the jet with the predictions of viscou s entrainment models and models of entrainment by expulsion of jet mat erial by internal shocks, and find that either type of model can expla in the general features of the observations.