Excitation of post-AGB Star Binary Eccentricity by Massive Polar-Aligned Circumbinary Disks
arXiv:2504.17125 · doi:10.3847/1538-4357/adcf1f
Abstract
Many post-AGB star binaries are observed to have relatively high orbital eccentricities (up to 0.6). Recently, AC Her was observed to have a polar-aligned circumbinary disk. We perform hydrodynamic simulations to explore the impact of a polar-aligned disk on the eccentricity of a binary. For a binary system with central masses of 0.73 M_sun and 1.4 M_sun, we find that a disk with a total mass of 0.1 M_sun can enhance the binary eccentricity from 0.2 to 0.7 within 5000 years, or from 0.01 to 0.65 within 15000 years. Even if the disk mass is as low as 0.01 M_sun, the binary eccentricity grows within our simulation time while the system remains stable. These eccentricity variations are associated with the variations of the inclination between the disk and the binary orbit due to von Zeipel-Kozai-Lidov oscillations. The oscillations eventually damp and leave the binary eccentricity at a high value. The numerical results are in good agreement with analytical estimates. In addition, we examine the AC-Her system and find that the disk mass should be on the order of 10^(-3)M_sun for the disk to remain polar.
Accepted for publication in The Astrophysical Journal. 11 pages, 11 figures
References in corpus (19)
- Smoothed Particle Hydrodynamics and Magnetohydrodynamics
- Keplerian discs around post-AGB stars: a common phenomenon?
- The Kozai-Lidov Mechanism in Hydrodynamical Disks
- Circumbinary Accretion from Finite and Infinite Disks
- Misaligned Disks in the Binary Protostar IRS 43
- Misaligned gas discs around eccentric black-hole binaries and implications for the final-parsec problem
- Interacting Binaries with Eccentric Orbits. Secular Orbital Evolution Due To Conservative Mass Transfer
- Polar alignment of a protoplanetary disk around an eccentric binary
- Inclination Evolution of Protoplanetary Disks Around Eccentric Binaries
- Linear Analysis of the Evolution of Nearly Polar Low Mass Circumbinary Discs
- Eccentricity and Spin-Orbit Misalignment in Short-Period Stellar Binaries as a Signpost of Hidden Tertiary Companions
- The Kozai-Lidov Mechanism in Hydrodynamical Disks. II. Effects of binary and disk parameters
- Alignment of a circumbinary disc around an eccentric binary with application to KH 15D
- The evolved circumbinary disk of AC Her: a radiative transfer, interferometric and mineralogical study
- Circumbinary discs for stellar population models
- Rocking shadows in broken circumbinary discs
- Keplerian disks and outflows in post-AGB stars: AC Herculis, 89 Herculis, IRAS 19125+0343, and R Scuti
- The eclipse of the V773 Tau B circumbinary disk
- Optical and Radio Observations of the T Tauri Binary KH 15D (V582 Mon): Stellar Properties, Disk Mass Limit and Discovery of a CO Outflow