Spectroscopic orbits of subsystems in multiple stars. IV. Double-lined pairs

TL;DR

This paper presents spectroscopic orbits for inner pairs in nine hierarchical multiple star systems, revealing their orbital parameters, mass ratios, and hierarchical structures, including some quadruple systems, through detailed analysis of double-lined spectroscopic binaries.

Contribution

It provides new spectroscopic orbital solutions for subsystems in multiple stars, including detailed parameters and hierarchical configurations, expanding understanding of stellar multiplicity.

Findings

Orbits for nine hierarchical systems' inner pairs are determined.

Five binaries are twins with equal masses.

Some systems are identified as 2+2 quadruples.

Abstract

Spectroscopic orbits are computed for inner pairs in 9 hierarchical multiple systems (HIP 19639, 60845, 75663, 76816, 78163, 78416, 80448, 84789, and HD 105080) and for one simple binary HIP 61840. All subsystems are double-lined, and their periods range from 2.27 to 30.4 days. Five spectroscopic binaries are twins with equal masses. Each hierarchical system is discussed individually, providing estimates of outer periods, masses, orbital inclination, and axial rotation. For systems with three resolved visual components (HIP 60845 and 80448), the outer and inner visual orbits are determined, complementing the description of their architecture. The radial velocities of HIP 75663A, 76816B, and 78163B are found to be variable with long periods, implying that these hierarchies are 2+2 quadruples. The period-eccentricity relation for spectroscopic subsystems is discussed.