Structurally relevant objects vs. satellites
Structurally relevant objects indicate the distinctive feature of a model, while satellites add additional information.
The Event and Function objects are typical of the Event-driven process chain model type and are therefore structurally relevant to a business process. You can use them to define the typical control flow.
The Organizational unit, Role, and Person objects can also be inserted into an Event-driven process chain. However, these objects do not represent the distinctive feature of a business process. As structurally irrelevant objects, they act as satellites, adding more detailed information to the process model. For example, you can insert organizational units and link them to functions to illustrate who carries out those functions. An object that can be inserted into a model or diagram but is not a structurally relevant object is called a satellite.