On the structure of steady stellar jets: an analytic model.

The authors present the results of an analytic study of the internal structure of steady stellar jets as a complement to previous numerical investigations. Special emphasis is made on the properties (shape, separation, etc.) of the crossing-shocks within the jet. The model is restricted to initially underexpanded, highly supersonic narrow jets moving into a uniform medium. Simple analytic expressions are given for the main parameters of the flow, such as the distance between crossing-shocks and the shock velocity. It is found that the shape of the incident shock is an arc of circumference passing through the injection point. Also, the authors show that the shock velocity is always ≡20 km s^-1 for radiative shocks with equilibrium temperature of ≡10⁴K, a result which is independent of the parameters of the jet as well as those of the ambient medium.