What is bow shock?

In aerodynamics, bow shock is a normal shock that occurs in front of an object within a supersonic flow. Unlike an oblique shock, the bow shock is not attached to the tip of the object in the flow. Oblique shock angles are limited in formation based on the corner angle and upstream Mach number. When these limitations are exceeded, a bow shock occurs instead of an oblique shock. So bow shocks are often seen forming around blunt objects. In astrophysics, bow shock is a boundary between a magnetosphere and an ambient medium. For stars, this is the boundary between their stellar wind and the interstellar medium. In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops because of its approach to the magnetopause.