Document Type

Article

Publication Date

4-10-2019

Publication Title

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press

Volume

486

Issue

2

First page number:

2919

Last page number:

2932

Abstract

We analyse the evolution of a mildly inclined circumbinary disc that orbits an eccentric orbit binary by means of smoothed particle hydrodynamics (SPH) simulations and linear theory. We show that the alignment process of an initially misaligned circumbinary disc around an eccentric orbit binary is significantly different than around a circular orbit binary and involves tilt oscillations. The more eccentric the binary, the larger the tilt oscillations and the longer it takes to damp these oscillations. A circumbinary disc that is only mildly inclined may increase its inclination by a factor of a few before it moves towards alignment. The results of the SPH simulations agree well with those of linear theory. We investigate the properties of the circumbinary disc/ring around KH 15D. We determine disc properties based on the observational constraints imposed by the changing binary brightness. We find that the inclination is currently at a local minimum and will increase substantially before settling to coplanarity. In addition, the nodal precession is currently near its most rapid rate. The recent observations that show a reappearance of star B impose constraints on the thickness of the layer of obscuring material. Our results suggest that disc solids have undergone substantial inward drift and settling towards to disc mid-plane. For disc masses ∼0.001 M⊙, our model indicates that the level of disc turbulence is low (α ≪ 0.001). Another possibility is that the disc/ring contains little gas.

Keywords

Accretion; Accretion discs; Hydrodynamics; Planets and satellites: formation; Binaries: general

Disciplines

Physical Processes | Stars, Interstellar Medium and the Galaxy

File Format

pdf

File Size

3.009 KB

Language

English

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