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Articles 1 - 30 of 208
Full-Text Articles in Astrophysics and Astronomy
The Response Of Atomic-To-Molecular Hydrogen Transition Points In Photodissociation Regions Due To A Hard X-Ray Spectrum, Gregory Joseph Colarch
The Response Of Atomic-To-Molecular Hydrogen Transition Points In Photodissociation Regions Due To A Hard X-Ray Spectrum, Gregory Joseph Colarch
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation develops a model for the response of the transition points in the density profiles from atomic (H0) to molecular (H2) hydrogen in a photodissociation region (PDR) due to a hard X-ray flux (HXR). A model for a steady-state PDR due to the photodissociation of H2 by the far-ultraviolet (FUV) Lyman-Werner radiation band is presented both analytically and computa- tionally. A steady state X-ray dissociation region (XDR) from an HXR in the 1 - 100 keV energy range is also developed both analytically and computationally. An analytic model is then developed by combining these two different steady state models. …
On Outflows Due To Radiation, Randall Cody Dannen
On Outflows Due To Radiation, Randall Cody Dannen
UNLV Theses, Dissertations, Professional Papers, and Capstones
Observations of ionized AGN outflows have provided compelling evidence that the radiation field transfers both momentum and energy to the plasma. At parsec scale distances in AGN, energy transfer can dominate, in which case the only force needed to launch an outflow is due to gas pressure. Much closer to the black hole, gravity dominates thermal energy due to insufficient heating by the radiation and the gas is in the so-called ’cold wind solution’ regime. Only magnetic or radiation forces can lead to outflow, but it is unclear how these forces depend on the spectral energy distribution (SED) and the …
Simulating Radial Ring Structure With An Ambipolar Elsasser (Am) Bump In Non-Ideal Magnetohydrodynamics Of Protoplanetary Disks, Aleksey S. Mohov
Simulating Radial Ring Structure With An Ambipolar Elsasser (Am) Bump In Non-Ideal Magnetohydrodynamics Of Protoplanetary Disks, Aleksey S. Mohov
UNLV Theses, Dissertations, Professional Papers, and Capstones
Rings are one of the most ubiquitous substructures observed in protoplanetary disks. They are known to be a robust site for planetesimal formation; thus we look for mechanisms that can originate stable rings. From chemical modelling of snow lines, we expect a bump in the Ambipolar Diffusion (AD) Elssaser number (Am) in the radial direction. We use the Athena++ code to model the non-ideal Magentohydrodynamics (MHD) behavior of an Am bump. We explore a parameter space of Gaussian bumps with Am = 5, 1, 0.5 peak strength and σ = 0.25, 1, 5. The Gaussian profile is inserted into the …
Inferring The Compositions And Interior Structures Of Small Planets, David R. Rice
Inferring The Compositions And Interior Structures Of Small Planets, David R. Rice
UNLV Theses, Dissertations, Professional Papers, and Capstones
Although there are now over 10,000 confirmed and candidate extrasolar planets, accurate masses and radii have been determined for around 200 planets of less than 10 Earth-masses. This number will grow exponentially over the next decade as extreme precision radial velocity spectrographs see first light. The densities of small planets hint at a diverse range of compositions for terrestrial worlds from super-Mercuries to super-Ganymedes. Uncertainty in density is as low as 3% in the Trappist-1 system. To determine composition from observed parameters, the community uses a variety of interior structure models. Underlying these models are multiple computational techniques, numerous experimental …
Joint Constraints On Kepler-36 From Kepler And New Keck-Hires Data, Nicholas Juliano
Joint Constraints On Kepler-36 From Kepler And New Keck-Hires Data, Nicholas Juliano
UNLV Theses, Dissertations, Professional Papers, and Capstones
I analyze new HIRES Radial Velocity (RV) data in conjunction with transit mid-times and uncertainties from the full 17 quarters of Kepler data to reassess the orbital parameters of the Kepler-36 system. Six additional RV measurements were taken by the Keck-HIRES spectrograph from September 21, 2021 to October 11, 2021. I carry out a differential evolution Markov Chain Monte Carlo-based (DEMCMC) analysis to infer improved orbital elements for the two known planets in the system. Leveraging additional information provided by the new RV measurements, I extend this DEMCMC analysis to a possible three-planet configuration. I explore the likelihood of a …
The Analysis Of Radio And X-Ray Energetics Of Fast Radio Bursts, Emily Huerta
The Analysis Of Radio And X-Ray Energetics Of Fast Radio Bursts, Emily Huerta
Undergraduate Research Symposium Posters
Here, we analyze the graphs and figures presented in Laha et al. (2022) and compare their slopes to our figures. Laha et al. (2022) includes two graphs, one that shows a comparison between radio fluence vs. x-ray fluence and radio energy vs. x-ray energy. In these graphs, the slopes are anywhere from 3.3e-14 to 2e-5, which are much less than unity. Our figures are consistent with these values, also providing slopes anywhere between the same range. Strong limits on this ratio between radio and x-ray energetics can either support the magnetar progenitor model, or completely dismiss it. Since we found …
3-D Visualizations Of Terrestial Exoplanet Interiors Generated With Magrathea In Blender, Tristan Benally, David Rice
3-D Visualizations Of Terrestial Exoplanet Interiors Generated With Magrathea In Blender, Tristan Benally, David Rice
Undergraduate Research Symposium Posters
There has been significant progress in simulating exoplanet interiors in the past decade. With the discovery of the TRAPPIST-1 system in the last few years, there have been many publications presenting models to best characterize specific aspects of exoplanets in study. However, with more parameters and considerations for different characteristics of an exoplanet there will be a need to represent many findings into a comprehensive model in the future. We extend the capabilities of MAGRATHEA from a planet interior solver to start incorporating multi-faceted functions starting with generating 3-D terrestrial planetary visualizations using a 3-D open-source computer graphic software called …
Transient Sources And How To Study Them: Selected Topics In Multi-Messenger Astronomy, Jiawei Luo
Transient Sources And How To Study Them: Selected Topics In Multi-Messenger Astronomy, Jiawei Luo
UNLV Theses, Dissertations, Professional Papers, and Capstones
The discovery of cosmic neutrino flux by IceCube, and the multi-messenger observations of gravitational event GW170817 ushered in the era of multi-messenger astronomy. Since the Universe itself is a natural laboratory, multi-messenger astronomy can help us study the most extreme physics processes in great detail. In this dissertation, we touch on some of the currently unanswered questions involving different types of transient sources and different “messengers” of multi-messenger astronomy. We employ a variety of analysis methods, including machine learning, a method that has not yet been widely adopted in astronomy but is rapidly gaining momentum.We start this dissertation with Chapter …
Day ‘N’ Nite: Habitability Of Tidally Locked Planets With Sporadic Rotation, Cody James Shakespeare
Day ‘N’ Nite: Habitability Of Tidally Locked Planets With Sporadic Rotation, Cody James Shakespeare
UNLV Theses, Dissertations, Professional Papers, and Capstones
Tidally locked worlds provide a unique opportunity for constraining the climates of detected exoplanets. They are unique in that few exoplanet spin and obliquity states are known or will be determined in the near future. The TRAPPIST-1 exoplanet system has multiple habitable zone planets that, in the past, have been presumed to be tidally locked. However, a recent study shows the dynamical conditions present in the TRAPPIST-1 system make rotation and large librations possible spin states for these planets. I confirm the tendency for these planets to sporadically transition from tidally locked libration to slow rotation using N-body simulations independent …
Polar Alignment Of Massive Retrograde Circumbinary Discs, Charles Abod
Polar Alignment Of Massive Retrograde Circumbinary Discs, Charles Abod
UNLV Theses, Dissertations, Professional Papers, and Capstones
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 …
Physics Of Electromagnetic Counterparts Of Binary-Neutron-Star Mergers, Shunke Ai
Physics Of Electromagnetic Counterparts Of Binary-Neutron-Star Mergers, Shunke Ai
UNLV Theses, Dissertations, Professional Papers, and Capstones
Binary neutron star (BNS) mergers are supposed to be the sources of a variety of astrophysical transients, including both gravitational wave (GW) and electromagnetic (EM) signals. The types and properties of the post-merger central product contain crucial information for many unsolved physical problems. Since the current GW detectors are not sensitive enough in kHz, only GWs from the inspiral phase can be detected, so that one cannot directly study the central products from GWs. EM signals can serve as probes to infer the type and properties of the central product. When a long-lived neutron star (NS) is formed after the …
Terrestrial Planet Formation In M-Dwarf And Binary Star Systems, Anna C. Childs
Terrestrial Planet Formation In M-Dwarf And Binary Star Systems, Anna C. Childs
UNLV Theses, Dissertations, Professional Papers, and Capstones
I examine circumbinary terrestrial planet formation in a gas free environment around various binary systems and terrestrial planet formation in a gaseous environment around M-dwarfs. While terrestrial cirumbinary planets have yet to be observed, this is likely due to observational bias. Motivated by recent observations of highly misaligned circumbinary gas disks, I perform a suite of n-body studies to understand the properties of terrestrial planets around various binary systems. In a polar alignment, a circumbinary disk is inclined by 90 degrees relative to the binary orbital plane. I find that terrestrial planet formation in a polar configuration may be as …
The Effects Of Winds On Accretion Disks And Spectra Of X-Ray Binaries And Active Galactic Nuclei, Shalini Ganguly
The Effects Of Winds On Accretion Disks And Spectra Of X-Ray Binaries And Active Galactic Nuclei, Shalini Ganguly
UNLV Theses, Dissertations, Professional Papers, and Capstones
Active galactic nuclei (AGNs) and X-ray binaries (XRBs) contain at their cores supermassive black holes (SMBH), and stellar mass black holes or neutron stars, respectively. These objects bind matter gravitationally, leading to the formation of accretion disks. The accretion of matter leads to efficient conversion of gravitational potential energy into radiation. When the force and/or energy imparted by this radiation on matter exceeds the attractive force due to the local gravitational field, it leads to the launching of matter in the form of outflows or winds. These outflows produce blueshifted (and occasionally redshifted) emission or absorption components in the spectra …
Viability Of Energy And Fuel Sources For Interstellar Travel; Design And Feasibility Of The Construction Of Manned Interstellar Space Shuttles, Lukas Mittelman
Viability Of Energy And Fuel Sources For Interstellar Travel; Design And Feasibility Of The Construction Of Manned Interstellar Space Shuttles, Lukas Mittelman
UNLV Theses, Dissertations, Professional Papers, and Capstones
The importance of proving the viability of interstellar transport and addressing its potential hazards and pitfalls is immense. If we do not look toward the future and examine what could be waiting for us, we are doing our children, our children’s children, and so on, a disservice. Here we must attempt to lay the groundwork for our future scientists, engineers, and adventurers. Asking and answering questions like, which propulsion and energy systems must we incorporate to send us through the cosmos? Will we utilize technologies known today, such as fossil fuel rockets, fission or fusion rockets, and antimatter drives (pion …
Miocene Ichnofaunas And Mammalian Communities In The Great Basin Region, Nevada And California, Annmarie R. Jones
Miocene Ichnofaunas And Mammalian Communities In The Great Basin Region, Nevada And California, Annmarie R. Jones
UNLV Theses, Dissertations, Professional Papers, and Capstones
The purpose of this dissertation is to document and interpret three new ichnofaunas and two fossil assemblages from the Neogene of Nevada and California. Ichnofossils are important for understanding behavior and geographical range of animals in the distant past and are key to locating and preserving sensitive material for future studies. I examined ichnofauna at three localities: two within the Mio-Pliocene Muddy Creek Formation of Nevada, and one within the Miocene China Ranch Beds of California. My research focuses primarily on (1) camelid and ursid ichnotaxa and how these new localities help in understanding the evolutionary history of these taxa …
Microbial Life In Deep-Subsurface Environments: The Role Of High Pressure In Biogeochemical Cycles, Cheyenne Brokaw
Microbial Life In Deep-Subsurface Environments: The Role Of High Pressure In Biogeochemical Cycles, Cheyenne Brokaw
Undergraduate Research Symposium Posters
Ocean World: An ocean world is considered any planet or moon currently with a liquid ocean. While the deepest part of the Ocean (Mariana Trench, 11,000 mbsl, 110 Mpa) and the lithosphere host microbial life, it begs the question, How?
Expanding The Library Of Planet Building Materials In Magrathea, Rosalie Chaleunsouck, Tristan Benally
Expanding The Library Of Planet Building Materials In Magrathea, Rosalie Chaleunsouck, Tristan Benally
Undergraduate Research Symposium Posters
Exoplanets are often modeled with fully-differentiated layers of iron, silicates, water, and gas. The large pressure and temperature ranges within each layer results in changes of phase and mineral equilibrium. MAGRATHEA is an open-course planet interior structure code with a large library of equations of state for planet building materials. This allows for the user to build detailed planet models and test differing measurements of the equation of state. We extend MAGRATHEA's library to include upper-mantle materials and various phases of iron cores. We show the impact of these materials on the characterization of rocky planet interiors.
Stability And Mechanical Properties Of W1-X Mox B4.2 (X=0.0-1.0) From First Principles, Weiguang Gong, Rui Xu, Xuecheng Shao, Quan Li, Changfeng Chen
Stability And Mechanical Properties Of W1-X Mox B4.2 (X=0.0-1.0) From First Principles, Weiguang Gong, Rui Xu, Xuecheng Shao, Quan Li, Changfeng Chen
Physics & Astronomy Faculty Research
Heavy transition-metal tetraborides (e.g., tungsten tetraboride, molybdenum tetraboride, and molybdenum-doped tungsten tetraboride) exhibit superior mechanical properties, but solving their complex crystal structures has been a long-standing challenge. Recent experimental x-ray and neutron diffraction measurements combined with first-principles structural searches have identified a complex structure model for tungsten tetraboride that contains a boron trimer as an unusual structural unit with a stoichiometry of 1:4.2. In this paper, we expand the study to binary MoB4.2 and ternary W1-xMoxB4.2 (x=0.0-1.0) compounds to assess their thermodynamic stability and mechanical properties using a tailor-designed crystal structure search method in conjunction with first-principles energetic calculations. Our …
Eccentric Neutron Star Disk Driven Type Ii Outburst Pairs In Be/X-Ray Binaries, Alessia Franchini, Rebecca G. Martin
Eccentric Neutron Star Disk Driven Type Ii Outburst Pairs In Be/X-Ray Binaries, Alessia Franchini, Rebecca G. Martin
Physics & Astronomy Faculty Research
Be star X-ray binaries are transient systems that show two different types of outbursts. Type I outbursts occur each orbital period while type II outbursts have a period and duration that are not related to any periodicity of the binary system. Type II outbursts may be caused by mass transfer to the neutron star from a highly eccentric Be star disk. A sufficiently misaligned Be star decretion disk undergoes secular Von Zeipel-Lidov-Kozai (ZLK) oscillations of eccentricity and inclination. Observations show that in some systems the type II outbursts come in pairs with the second being of lower luminosity. We use …
Nonperiodic Type I Be/X-Ray Binary Outbursts, Rebecca G. Martin, Alessia Franchini
Nonperiodic Type I Be/X-Ray Binary Outbursts, Rebecca G. Martin, Alessia Franchini
Physics & Astronomy Faculty Research
Type I Be/X-ray binary outbursts are driven by mass transfer from a Be star decretion disk to a neutron star companion during each orbital period. Treiber et al. recently observed nonperiodic type I outbursts in RX J0529.8-6556 that has unknown binary orbital properties. We show that nonperiodic type I outbursts may be temporarily driven in a low eccentricity binary with a disk that is inclined sufficiently to be mildly unstable to Kozai-Lidov oscillations. The inclined disk becomes eccentric and material is transferred to the neutron star at up to three locations in each orbit: when the neutron star passes the …
Global 3d Radiation Hydrodynamic Simulations Of Proto-Jupiter’S Convective Envelope, Zhaohuan Zhu, Yan-Fei Jiang, Hans Baehr, Andrew N. Youdin, Philip J. Armitage, Rebecca G. Martin
Global 3d Radiation Hydrodynamic Simulations Of Proto-Jupiter’S Convective Envelope, Zhaohuan Zhu, Yan-Fei Jiang, Hans Baehr, Andrew N. Youdin, Philip J. Armitage, Rebecca G. Martin
Physics & Astronomy Faculty Research
The core accretion model of giant planet formation has been challenged by the discovery of recycling flows between the planetary envelope and the disc that can slow or stall envelope accretion. We carry out 3D radiation hydrodynamic simulations with an updated opacity compilation to model the proto-Jupiter’s envelope. To isolate the 3D effects of convection and recycling, we simulate both isolated spherical envelopes and envelopes embedded in discs. The envelopes are heated at given rates to achieve steady states, enabling comparisons with 1D models. We vary envelope properties to obtain both radiative and convective solutions. Using a passive scalar, we …
Initial Acoustoelastic Measurements In Olivine: Investigating The Effect Of Stress On P- And S-Wave Velocities, Taryn K. Traylor, Pamela C. Burnley, M. L. Whitaker
Initial Acoustoelastic Measurements In Olivine: Investigating The Effect Of Stress On P- And S-Wave Velocities, Taryn K. Traylor, Pamela C. Burnley, M. L. Whitaker
Geoscience Faculty Publications
It is well known that elasticity is a key physical property in the determination of the structure and composition of the Earth and provides critical information for the interpretation of seismic data. This study investigates the stress-induced variation in elastic wave velocities, known as the acoustoelastic effect, in San Carlos olivine. A recently developed experimental ultrasonic acoustic system, the Directly Integrated Acoustic System Combined with Pressure Experiments (DIASCoPE), was used with the D-DIA multi-anvil apparatus to transmit ultrasonic sound waves and collect the reflections. We use the DIASCoPE to obtain longitudinal (P) and shear (S) elastic wave velocities from San …
Gw Ori: Circumtriple Rings And Planets, Jeremy L. Smallwood, Rebecca Nealon, Cheng Chen, Rebecca G. Martin, Jiaqing Bi, Ruobing Dong, Christophe Pinte
Gw Ori: Circumtriple Rings And Planets, Jeremy L. Smallwood, Rebecca Nealon, Cheng Chen, Rebecca G. Martin, Jiaqing Bi, Ruobing Dong, Christophe Pinte
Physics & Astronomy Faculty Research
GW Ori is a hierarchical triple star system with a misaligned circumtriple protoplanetary disc. Recent Atacama Large Millimeter/submillimeter Array observations have identified three dust rings with a prominent gap at 100 au and misalignments between each of the rings. A break in the gas disc may be driven by the torque from either the triple star system or a planet that is massive enough to carve a gap in the disc. Once the disc is broken, the rings nodally precess on different time-scales and become misaligned. We investigate the origins of the dust rings by means of N-body integrations and …
Inelastic, Exchange, And Reactive Processes In Rovibrationally Excited Collisions Of Hd With H, Boyi Zhou, Benhui Yang, Balakrishnan Naduvalath, B. K. Kendrick, Maodu Chen, P. C. Stancil
Inelastic, Exchange, And Reactive Processes In Rovibrationally Excited Collisions Of Hd With H, Boyi Zhou, Benhui Yang, Balakrishnan Naduvalath, B. K. Kendrick, Maodu Chen, P. C. Stancil
Chemistry and Biochemistry Faculty Research
The HD molecule is an important coolant in early universe chemistry models and a tracer of H2 in star-forming regions. Rate coefficients for collisional excitation and de-excitation of HD rotational and vibrational levels form important ingredients in astrophysical models. While collisions with He, H2, and H are the most important, available data for H + HD collisions are largely limited to temperatures less than 1000 K for the vibrational ground state, low-lying rotational levels of the v = 1 HD vibrational level, or computed without reactive contributions. Here, through explicit quantum scattering calculations, we report extensive data for rovibrational transitions …
Terrestrial Planet Formation In A Circumbinary Disc Around A Coplanar Binary, Anna C. Childs, Rebecca G. Martin
Terrestrial Planet Formation In A Circumbinary Disc Around A Coplanar Binary, Anna C. Childs, Rebecca G. Martin
Physics & Astronomy Faculty Research
With N-body simulations, we model terrestrial circumbinary planet (CBP) formation with an initial surface density profile motivated by hydrodynamic circumbinary gas disc simulations. The binary plays an important role in shaping the initial distribution of bodies. After the gas disc has dissipated, the torque from the binary speeds up the planet formation process by promoting body-body interactions but also drives the ejection of planet building material from the system at an early time. Fewer but more massive planets form around a close binary compared to a single star system. A sufficiently wide or eccentric binary can prohibit terrestrial planet formation. …
The Large Area Burst Polarimeter (Leap) A Nasa Mission Of Opportunity For The Iss, Bing Zhang, Numerous Authors, See Full List Below
The Large Area Burst Polarimeter (Leap) A Nasa Mission Of Opportunity For The Iss, Bing Zhang, Numerous Authors, See Full List Below
Physics & Astronomy Faculty Research
The LargE Area Burst Polarimeter (LEAP) will radically improve our understanding of some of the most energetic phenomena in our Universe by exposing the underlying physics that governs astrophysical jets and the extreme environment surrounding newborn compact objects. LEAP will do this by making the highest fidelity polarization measurements to date of the prompt gamma-ray emission from a large sample of Gamma-Ray Bursts (GRBs). The science objectives are met with a single instrument deployed as an external payload on the ISS-a wide FOV Compton polarimeter that measures GRB polarization from 50-500 keV and GRB spectra from ∼10 keV to 5 …
Free-Free Absorption In Hot Relativistic Flows: Application To Fast Radio Bursts, Esha Kundu, Bing Zhang
Free-Free Absorption In Hot Relativistic Flows: Application To Fast Radio Bursts, Esha Kundu, Bing Zhang
Physics & Astronomy Faculty Research
Magnetic flares create hot relativistic shocks outside the light cylinder radius of a magnetized star. Radio emission produced in such a shock or at a radius smaller than the shock undergoes free–free absorption while passing through the shocked medium. In this work, we demonstrate that this free–free absorption can lead to a negative drift in the frequency-time spectra. Whether it is related to the downward drift pattern observed in fast radio bursts (FRBs) is unclear. However, if the FRB down-drifting is due to this mechanism then it will be pronounced in those shocks that have isotropic kinetic energies ≳1044 erg. …
A Mechanical Model For Magnetized Relativistic Blastwaves, Shunke Ai, Bing Zhang
A Mechanical Model For Magnetized Relativistic Blastwaves, Shunke Ai, Bing Zhang
Physics & Astronomy Faculty Research
The evolution of a relativistic blastwave is usually delineated under the assumption of pressure balance between forward- and reverse-shocked regions. However, such a treatment usually violates the energy conservation law, and is inconsistent with existing magnetohydrodynamic numerical simulation results. A mechanical model of non-magnetized blastwaves was proposed in previous work to solve the problem. In this paper, we generalize the mechanical model to the case of a blastwave driven by an ejecta with an arbitrary magnetization parameter $\sigma_{\rm ej}$. We test our modified mechanical model by considering a long-lasting magnetized ejecta and found that it is much better than the …
Orbital Dynamics And Stability Of Circumbinary Planetary Systems And Small Bodies In The Solar System, Cheng Chen
Orbital Dynamics And Stability Of Circumbinary Planetary Systems And Small Bodies In The Solar System, Cheng Chen
UNLV Theses, Dissertations, Professional Papers, and Capstones
My main research focuses on the dynamics and stability of circumbinary planetary systems and of small bodies in the solar system. Unlike the two-body problem, the three-body problem is more complex as there are stronger interactions with two massive bodies in the system. In the outer solar system, the apsidal precession secular resonance with Neptune makes comets in the Kuiper belt unstable in the early stages of the solar system. This resonance a likely origin for the nitrogen-delivering comets that impacted the Earth bringing some of the nitrogen in the Earth’s atmosphere today. Beyond the solar system, we have observed …
Accretion And Debris Disc Dynamics Around Single And Higher-Order Star Systems, Jeremy L. Smallwood
Accretion And Debris Disc Dynamics Around Single And Higher-Order Star Systems, Jeremy L. Smallwood
UNLV Theses, Dissertations, Professional Papers, and Capstones
My research deals with highly topical areas of astrophysics, such as planet habitability, stellar evolution, the origin of fast radio bursts, the evolution of debris discs, and the dynamics of accretion discs in binary and higher-order star systems. Accretion discs around binary star systems are ubiquitous in the galaxy and planet formation is thought to occur within these discs. Circumbinary discs are commonly observed to be misaligned with respect to the binary orbital plane. A misaligned circumbinary disc eventually evolve to a stable orientation, either coplanar or polar with the binary orbital plane. The process of disc alignment has important …