SIMBAD references

A new solution method is presented for steady state, momentum-conserving, nonaxisymmetric bow shocks and colliding winds in the thin-shell limit. This is a generalization of previous formulations to include a density gradient in the preshock ambient medium as well as anisotropy in the preshock wind. For cases where the wind is unaccelerated, the formalism yields exact, analytic solutions.

Solutions are presented for two bow shock cases: (1) that due to a star moving supersonically with respect to an ambient medium with a density gradient perpendicular to the stellar velocity, and (2) that due to a star with a misaligned, axisymmetric wind moving in a uniform medium. It is also shown under quite general circumstances that the total rate of energy thermalization in the bow shock is independent of the details of the wind asymmetry, including the orientation of the nonaxisymmetric driving wind, provided the wind is nonaccelerating and point-symmetric. A typical feature of the solutions is that the region near the standoff point is tilted so that the star does not lie along the bisector of a parabolic fit to the standoff region. The principal use of this work is to infer the origin of bow shock asymmetries, whether due to the wind or ambient medium or both.