THE PRECESSION OF THE HERBIG-HARO 111 FLOW IN THE INFRARED

We present Spitzer Infrared Array Camera images of the Herbig-Haro (HH) 111 outflow that show a wealth of condensations/knots in both jet and counterjet. Studying the positional distribution of these knots, we find very suggestive evidence of a mirror symmetric pattern in the jet/counterjet flow. We model this pattern as the result of an orbital motion of the jet source around a binary companion. From a fit of an analytic, ballistic model to the observed path of the HH 111 system, we find that the motion in a binary with two ∼1 Msun stars (one of them being the HH 111 source), in a circular orbit with a separation of ∼186 AU, would produce the mirror symmetric pattern seen in the outflow.