Inner and Outer Orbits in 13 Resolved Hierarchical Stellar Systems

TL;DR

This study computes and updates the orbits of 13 hierarchical stellar systems to analyze their orbital inclinations, period ratios, and masses, providing new orbital data and insights into their dynamics.

Contribution

It presents new orbital solutions for several systems and models the impact of subsystems on outer orbit motion, enhancing understanding of hierarchical stellar system dynamics.

Findings

Four astrometric inner orbits and one outer orbit are computed for the first time.

Inner periods range from 1.7 to 49 years, outer periods from 83 to 2400 years.

Some long-period outer orbits are poorly constrained.

Abstract

Orbits of inner and outer subsystems in 13 triple or higher-order stellar systems are computed or updated using position measurements and, in three cases, radial velocities. The goal is to determine mutual orbital inclinations, period ratios, and masses to complement the statistics of hierarchical systems. Effect of the subsystems on the motion in the outer orbits (wobble) is explicitly modeled to determine inner mass ratios. Stars studied here (HD 5408, 8036, 9770, 15089, 29310, 286955, 29316, 140538, 144362, 154621, 156034, 185655, and 213235) are bright and nearby (from 15\,pc to 150\,pc). Their inner periods range from 1.7 yr to 49 yr, and the outer periods from 83 to 2400 yr. Some long-period outer orbits are poorly constrained. Four astrometric inner orbits and one outer orbit are computed for the first time.