What is the angle between the asymptotes of a hyperbolic trajectory known as?

Angle of deflection. The angle between the asymptotes of a hyperbolic trajectory is referred to as the angle of deflection. This angle is a characteristic parameter of hyperbolic trajectories, which are followed by objects that have excess kinetic energy compared to the gravitational potential energy between them and the central body. The asymptotes of a hyperbola represent the straight lines that the trajectory approaches as it extends to infinity. The angle of deflection, measured between these asymptotes, provides a way to describe the shape and orientation of the hyperbolic path. In gravitational slingshot maneuvers used by spacecraft for velocity boosts, the angle of deflection is a crucial factor in determining the change in the spacecraft's trajectory and the resulting increase in speed.