The term heating is used in astronomy in its normal sense but also occasionally for an analogous phenomenon, and you sometimes have to infer the intended meaning. The analogous phenomenon is the dynamics of large groups of astronomical objects, particularly stars, treating them as you would the particles moving around in a gas in the kinetic theory of gases, i.e., heating is increasing the average velocities of the moving particles/objects. This usage is most common for the stars of a galaxy or stellar cluster. Such stars attract and basically never "bounce", but their near misses do drastically change the velocities of the objects, much as do the colliding molecules of a gas. Such near misses of the objects are analogously termed collisions. Some phrases:
Equations originally for modeling the temperature of gases have been borrowed for modeling the stellar interactions in globular clusters and galactic bulges.