Binary star orbits from speckle interferometry. 7: The multiple system XI Ursae Majoris

Abstract

Xi Ursae Majoris (HR 4374/5) consists of a visual binary having a period of nearly 60 yr, the primary component of which is a 669 day astrometric and spectroscopic subsystem, and the secondary is a 4 day spectroscopic binary. We report here improved elements for the long-period visual system (AB) and the short-period astrometric system (Aa). We also report the first direct detection of a fifth component to the multiple system (Bc) from speckle observations obtained in 1988 at the Canada-France-Hawaii Telescope.