Abstract

Even when we cannot resolve two (or more) sources we can often still identify a multiple star system from its motion. The Gaia survey has brought the level of astrometric precision down to the point where binary(+) systems can be found in their thousands. In this talk I’ll show how even in existing data, limited to single-body fits and the associated error, the persistent excess motion caused by a binary translates into an identifiable signal. Furthermore the most recent data release (eDR3) allows us to track astrometric errors over time and by comparing to previous observations allows us to better seperate multiple stellar systems from background noise. Finally, I’ll talk about the future capacity of the survey to detect astrometric binaries, including which pairings of stellar types and compact objects will give the largest signals and most numerous additions to the census of binary systems.