Growth and Dissipation of Be Star Discs in Misaligned Binary Systems

Abstract

We use a three-dimensional smoothed particle hydrodynamics code to simulate growth and dissipation of Be star discs in systems where the binary orbit is misaligned with respect to the spin axis of the primary star. We investigate six different scenarios of varying orbital period and misalignment angle, feeding the disc at a constant rate for 100 orbital periods, and then letting the disc dissipate for 100 orbital periods. During the disc growth phase, we find that the binary companion tilts the disc away from its initial plane at the equator of the primary star before settling to a constant orientation after 40 to 50 orbital periods. While the mass-injection into the disc is ongoing, the tilting of the disc can cause material to reaccrete onto the primary star prematurely. Once disc dissipation begins, usually the disc precesses about the binary companion's orbital axis with precession periods ranging from 20 to 50 orbital periods. In special cases we detect phenomena of disc tearing, as well as Kozai-Lidov oscillations of the disc. These oscillations reach a maximum eccentricity of about 0.6, and a minimum inclination of about \ang{20} with respect to the binary's orbit. We also find the disc material to have highly eccentric orbits beyond the transition radius, where the disc changes from being dominated by viscous forces, to heavily controlled by the companion star, in contrast to its nearly circular motion inward of the transition radius. Finally, we offer predictions to how these changes will affect Be star observables.

arXiv comment14 pages, 14 figures

References in corpus (36)

• Modelling Accretion in Protobinary Systems
• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• Classical Be Stars: Rapidly Rotating B Stars with Viscous Keplerian Decretion Disks
• Secular Dynamics in Hierarchical Three-Body Systems
• The tidally induced warping, precession and truncation of accretion discs in binary systems: three-dimensional simulations
• NLTE Monte Carlo Radiative Transfer: I. The Thermal Properties of Keplerian Disks around Classical Be Stars
• Viscous Effects on the Interaction between the Coplanar Decretion Disc and the Neutron Star in Be/X-Ray Binaries
• Tidal Truncation of Inclined Circumstellar and Circumbinary Discs in Young Stellar Binaries
• The Kozai-Lidov Mechanism in Hydrodynamical Disks
• Giant Outbursts in Be/X-ray Binaries
• Dynamical Evolution of Viscous Disks around Be Stars. I: photometry
• A naked-eye triple system with a nonaccreting black hole in the inner binary
• Tidal Torques on Misaligned Disks in Binary Systems
• Tearing up a misaligned accretion disc with a binary companion
• Investigating the lack of main-sequence companions to massive Be stars
• Short-term variability and mass loss in Be stars I. BRITE satellite photometry of $\eta$ and $\mu$ Centauri
• The life cycles of Be viscous decretion discs: fundamental disc parameters of 54 SMC Be stars
• Prevalence of SED turndown among classical Be stars: Are all Be stars close binaries?
• Tidal Warping of Be Star Decretion Discs
• Be discs in binary systems I. Coplanar orbits
• The Kozai-Lidov Mechanism in Hydrodynamical Disks. II. Effects of binary and disk parameters
• Dynamical Evolution of Viscous Disks around Be Stars. II : polarimetry
• The life cycles of Be viscous decretion discs: The case of ω CMa
• Be discs in coplanar circular binaries: Phase-locked variations of emission lines
• The Kozai-Lidov Mechanism in Hydrodynamical Disks. III. Effects of Disk Mass and Self-Gravity
• Lidov-Kozai Mechanism in Hydrodynamical Disks: Linear Stability Analysis
• Be discs in binary systems: II. Misaligned orbits
• Kozai-Lidov Disc Instability
• On the Intrinsic Continuum Linear Polarization of Classical Be Stars during Disk Growth and Dissipation
• The binary fraction and mass-ratio of Be and B stars: a comparative VLT/NACO study
• The Be Star 66 Ophiuchi: 60 Years of Disk Evolution
• A Multi-observing-technique Study of the Dynamical Evolution of the Viscous Disk around the Be Star $\omega$ CMa
• Modelling decretion discs in Be/X-ray binaries
• The frequency of Kozai-Lidov disc oscillation driven giant outbursts in Be/X-ray binaries
• $\nu$ Gem: a hierarchical triple system with an outer Be star
• A fast-growing tilt instability of detached circumplanetary disks

Cited by in corpus (16)

• To Be or not to Be: the role of rotation in modeling Galactic Be X-ray Binaries
• Ultraviolet Spectropolarimetry: on the origin of rapidly rotating B stars
• The Role of Disk Tearing and Precession in the Observed Variability of Pleione
• The X-ray emission of gamma Cassiopeiae during the 2020-2021 disc eruption
• Eccentric neutron star disk driven type II outburst pairs in Be/X-ray binaries
• The binary system of the spinning-top Be star Achernar
• High-spatial-resolution simulations of Be star disks in binary systems: I. Structure and kinematics of coplanar disks
• Superorbital periods of Be/X-ray binaries driven by stellar spin precession
• Tidal truncation of circumplanetary disks fails above a critical disk aspect ratio
• A Time-Dependent Spectral Analysis of $\gamma$ Cassiopeiae
• Fast nodal precession of the disc around Pleione requires a broken disc
• Retrograde discs around one component of a binary are unstable to tilting
• A precessing stellar disk model for superorbital modulations of the gamma-ray binary LS I+61${}^{\circ }$ 303
• Strong Variability in AzV 493, an Extreme Oe-Type Star in the SMC
• Disc breaking through forced eccentricity growth
• Non-periodic type I Be/X-ray binary outbursts