On utmost multiplicity of hierarchical stellar systems

TL;DR

This study investigates the maximum possible multiplicity of hierarchical stellar systems by analyzing catalog data, finding systems with up to 12 components and discussing why higher multiplicities are rare.

Contribution

It provides a catalog of high-multiplicity stellar systems and explores reasons for the observed upper limit in system complexity.

Findings

Identified 10 candidate systems with up to 12 components.

Confirmed some systems contain binary or multiple subsystems.

Discussed potential explanations for the rarity of higher multiplicity systems.

Abstract

According to theoretical considerations, multiplicity of hierarchical stellar systems can reach, depending on masses and orbital parameters, several hundred, while observational data confirm existence of at most septuple (seven-component) systems. In this study, we cross-match very high multiplicity (six and more components) stellar systems in modern catalogues of visual double and multiple stars, to find candidates to hierarchical systems among them. After cross-matching with catalogues of closer binaries (eclipsing, spectroscopic, etc.), some of their components were found to be binary/multiple themselves, which increases the system's degree of multiplicity. Optical pairs, known from literature or filtered by the authors, are flagged and excluded from the statistics. We have compiled a list of potentially very high multiplicity hierarchical systems that contains 10~objects. Their multiplicity does not exceed 12, and we discuss a number of ways to explain the lack of extremely high multiplicity systems.