We present an analytic, ballistic model for quasi-symmetric jet/counterjet systems, considering both the non-relativistic and the relativistic cases. The model considers the presence of ejection time and velocity asymmetries, which produce offsets between the positions of the knots in jet/counterjet…

Within ≈30" from the outflow source, the HH34 jet has a chain of well aligned knots. The positions and proper motions of these knots can be used to determine dynamical timescales, and estimates of the ejection period (by taking differences…