Award Date


Degree Type


Degree Name

Master of Science (MS)


Physics and Astronomy

First Committee Member

Rebecca Martin

Second Committee Member

Zhaohuan Zhu

Third Committee Member

Stephen Lepp

Fourth Committee Member

Laurel Raftery

Number of Pages



To understand the observed circumbinary planetary systems, we must first explain the dynamics of the circumbinary discs in which they formed. Observations of circumbinary discs show that misalignments to the binary orbital plane may be common. Here we investigate these systems by exploring the orbital dynamics of three-body systems and circumbinary discs. A test particle orbit around an eccentric binary has two stationary states in which there is no nodal precession: coplanar and polar. Nodal precession of a misaligned test particle orbit centres on one of these stationary states. A low mass circumbinary disc undergoes the same precession and moves towards one of these states through dissipation within the disc. For a massive particle orbit, the stationary polar alignment occurs at an inclination less than $90^{\circ}$, this is the prograde stationary inclination. A sufficiently high angular momentum particle has an additional higher inclination stationary state, the retrograde stationary inclination. Misaligned particle orbits close to the retrograde stationary inclination are not nested like the orbits close to the other stationary points. We investigate the evolution of a gas disc that begins close to the retrograde stationary inclination. With hydrodynamical disc simulations, we find that the disc moves through the unnested crescent shape precession orbits and eventually moves towards the prograde stationary inclination thus increasing the parameter space over which circumbinary discs move towards polar alignment. This has implications for the alignment of circumbinary planets.


accretion; accretion discs; binaries; circumbinary disc; orbital dynamics


Astrophysics and Astronomy

File Format


File Size

1581 KB

Degree Grantor

University of Nevada, Las Vegas




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