THE DYNAMICS OF A JET IN A SUPERSONIC SIDE WIND

We study the problem of a jet ejected from a source, which has a super sonic relative velocity with respect to the surrounding environment. W e find that while the adiabatic problem (appropriate for extragalactic jets) has to be solved numerically, the isothermal problem (appropria te for Herbig-Haro jets) does have a complete analytic solution. Furth ermore, we show that the adiabatic solutions (for any value of the spe cific heat ratio gamma) converge to the isothermal solution in the reg ion close to the stagnation point of the flow. Because of this, the an alytic isothermal solution can be used for comparisons with observatio ns of curved jets in both the isothermal and adiabatic regimes. Finall y, we present a comparison of our model with observations of the curve d Herbig-Haro now HH 30.