A Strong Candidate for a Previously Unreported Hierarchical Triple System in Gaia DR3

Abstract

We report a strong candidate for a previously unreported hierarchical triple system identified in Gaia Data Release 3. The inner system, Gaia DR3 6421608365364830848, has a high-significance astrometric orbital solution with a period of 605.5067 ± 0.8835 days and eccentricity 0.0526 ± 0.0096. A second Gaia source, 6421608365364830976, lies at an angular separation of 2.8402 arcsec and shows highly consistent parallax and proper motion. The projected physical separation is approximately 971 AU at the Gaia parallax distance of about 342 pc. Local Gaia density tests find no other source within 60 arcsec satisfying the same broad astrometric criteria. These results strongly support the interpretation of the system as a hierarchical triple candidate. A spectroscopic radial-velocity measurement for the wide component is still required for a definitive three-dimensional confirmation of physical binding.