Orbits of Twelve Multiple Stars

TL;DR

This study determines the orbits and component masses of twelve hierarchical stellar systems by combining high-resolution speckle imaging, CHIRON radial velocities, and space-based parallaxes. A joint orbit-fitting approach accounts for wobble from unresolved inner subsystems and uses photometric masses as constraints, yielding orbital solutions for inner and outer pairs across 8 triples and 4 3+1 quadruples. Notable results include the discovery of a new contact eclipsing pair in HIP 97922 and the Gaia-confirmed compact quadruple HIP 102855, with mutual inclinations measured where data permit. The work provides robust dynamical masses and detailed architectures that inform formation and dynamical-evolution scenarios for stellar hierarchies, while highlighting the continued need for targeted ground-based observations to complement Gaia in complex systems.

Abstract

Inner and outer orbits in twelve hierarchical stellar systems are determined using high-resolution speckle imaging, radial velocities, or both. Masses and fluxes of the components are estimated. The Hipparcos numbers of the main stars are 7111, 12912, 17895, 20375, 42424, 68717, 77439, 79076, 90253, 97922, and 102855; the faint triple WDS J10367+1522 has no HIP number. Four systems are quadruple of 3+1 hierarchy, the rest are triple. Two triples with low-mass M-type components are approximately planar, with moderately eccentric orbits and near-unit mass ratios. The shortest inner period of 0.27d is found in the newly identified contact eclipsing pair belonging to the misaligned quadruple HIP 97922. The compact system HIP 102855 (periods 15.4 and 129 days) identified by Gaia is confirmed here and has additional companion at 6 arcseconds. This work contributes new data for the study of diverse architectures of stellar hierarchies in the field.