Dancing twins: stellar hierarchies that formed sequentially?

Abstract

This paper attracts attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer component. Such systems could be formed either sequentially (inside-out) by disk fragmentation with subsequent accretion and migration or by a cascade hierarchical fragmentation of a rotating cloud. Orbits of the outer and inner subsystems are computed or updated in four such hierarchies: LHS 1070 (GJ 2005, periods 77.6 and 17.25 years), HIP 9497 (80 and 14.4 years), HIP 25240 (1200 and 47.0 years), and HIP 78842 (131 and 10.5 years).

8 pages, 7 figures, 4 tables. Accepted by Astronomical Journal

References in corpus (7)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• Comparative statistics and origin of triple and quadruple stars
• The Updated Multiple Star Catalog
• Orbit alignment in triple stars
• Orbits and Masses in the multiple system LHS 1070
• The unusual quadruple system HD 91962 with a "planetary" architecture

Cited by in corpus (23)

• Photodynamical analysis of the triply eclipsing hierarchical triple system EPIC 249432662
• Speckle interferometry at SOAR in 2018
• Speckle interferometry at SOAR in 2016 and 2017
• Orbital Parameter Determination for Wide Stellar Binary Systems in the Age of Gaia
• CoBiToM Project -- I. Contact Binaries Towards Merging
• Eclipse timing variation analysis of OGLE-IV eclipsing binaries toward the Galactic Bulge. I. Hierarchical triple system candidates
• Doubly eclipsing systems
• The HD 98800 quadruple pre-main sequence system. Towards full orbital characterisation using long-baseline infrared interferometry
• Inner and Outer Orbits in 13 Resolved Hierarchical Stellar Systems
• Speckle observations and orbits of multiple stars
• BG Ind: the nearest doubly eclipsing, compact hierarchical quadruple system
• Shrinking orbits in hierarchical quadruple star systems
• Constraints on star formation in NGC2264
• Von Zeipel - Lidov - Kozai cycles in action: $Kepler$ triples with eclipse depth variations: KICs 6964043, 5653126, 5731312 and 8023317
• Eclipse timing variation analysis of OGLE-IV eclipsing binaries toward the Galactic Bulge. II. Short periodic triple stellar systems
• The Dynamical Roche Lobe in Hierarchical Triples
• Long-term stability of planets in and around binary stars
• Mergers prompted by dynamics in compact, multiple-star systems: a stellar-reduction case for the massive triple TIC 470710327
• The McDonald Accelerating Stars Survey (MASS): Architecture of the Ancient Five-Planet Host System Kepler-444
• Tidal breakup of quadruple stars in the Galactic Centre
• Exploring Thousands of Nearby Hierarchical Systems with Gaia and Speckle Interferometry
• Bayes-based orbital elements estimation in triple hierarchical stellar systems
• Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids: Final Results