What is indicated by a waypoint with a circle around it on a STAR?

A waypoint with a circle around it on a Standard Terminal Arrival Route (STAR) signifies that the aircraft must fly over that specific point. This is important for ensuring that the aircraft follows the designated route as they transition into the terminal airspace. Flyover points can be critical for maintaining spacing and managing traffic, as they ensure that the aircraft is precisely navigated over certain locations for optimal operations during arrival.

In contrast, a mandatory altitude requirement would generally be indicated through specific altitude restrictions noted on the chart, while a holding pattern would usually be marked differently within the context of the routing. The need for a descent at a particular point may be indicated by different markings or annotations, emphasizing specific vertical speeds rather than a flyover requirement.