Understanding Fomalhaut as a Cooper pair

Understand

Fomalhaut is a nearby stellar system and has been found to be a triple based on astrometric observations.

• With new radial velocity and astrometric data, we study the association between Fomalhaut A, B, and C in a Bayesian framework finding that the system is gravitationally bound or at least associated.
• Based on simulations of the system, we find that Fomalhaut C can be easily destabilized through combined perturbations from the Galactic tide and stellar encounters.
• Considering that observing the disruption of a triple is probably rare in the solar neighbourhood, we conclude that Fomalhaut C is a so-called "gravitational pair" of Fomalhaut A and B.