Spectroscopic Orbits of Subsystems in Multiple Stars. XI

TL;DR

This paper reports spectroscopic orbits for four multiple star systems and evaluates Gaia data on low-mass dwarf systems, highlighting the importance of combined observational methods for understanding stellar hierarchies.

Contribution

It provides new spectroscopic orbits for four hierarchical systems and assesses Gaia's capabilities in detecting and confirming multiple star configurations.

Findings

Confirmed five Gaia orbits of low-mass dwarf systems

Identified hierarchical structures including quadruples, quintuple, and triple systems

Highlighted the strengths and limitations of Gaia data for multiple star analysis

Abstract

Adding to the large radial velocity survey of nearby solar-type stars (summary in Tokovinin, 2023a), spectroscopic orbits are determined for four hierarchical systems: HIP 49442 (inner and outer periods of 164.55 d and 34 yr, respectively), HIP 55691 (2.4 and 415 yr), HIP 61465 (86.8 d), and HIP 78662C (0.82 d). Each system is discussed individually. Seven Gaia orbits of low-mass dwarfs, each with two additional resolved (interferometric and wide) companions, i.e. potential quadruples, are tested by monitoring radial velocities; five orbits are confirmed and two are refuted. Five of these systems are quadruples of 3+1 hierarchy, one is quintuple, and one is triple. Strengths and limitations of the Gaia data on multiple systems and the need of complementary observations are highlighted.