From Pluralpedia, the collaborative plurality dictionary
cosmogenic (adj.)
Applies tosystems, headmates
CoinerPenumbra of the Infinity's End System

A cosmogenic system or headmate identifies the cause of their manifestation to be or relate to the cosmos or celestial forces to which Earth is, but one infinitesimal mote amongst the reaches of space and time.

This does not refer to a headmate who identifies as cosmic, only their origin (though a cosmic headmate may identify as cosmogenic as well).