# Jeremy L. Smallwood's research while affiliated with Baylor University and other places

## Publications (24)

Preprint
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 wit...
Article
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 wit...
Article
We present hydrodynamical simulations to model the accretion flow from a polar circumbinary disc on to a high eccentricity (e = 0.78) binary star system with near unity mass ratio (q = 0.83), as a model for binary HD 98800 BaBb. We compare the polar circumbinary disc accretion flow with the previously studied coplanar case. In the coplanar case, th...
Preprint
We present hydrodynamical simulations to model the accretion flow from a polar circumbinary disc onto a high eccentricity ($e=0.78$) binary star system with near unity mass ratio ($q=0.83$), as a model for binary HD 98800 BaBb. We compare the polar circumbinary disc accretion flow with the previously studied coplanar case. In the coplanar case, the...
Preprint
GW Ori is a hierarchical triple star system with a misaligned circumtriple protoplanetary disc. Recent ALMA observations have identified three dust rings with a prominent gap at $100\, \rm au$ and misalignments between each of the rings. A break in the gas disc may be driven either by the torque from the triple star system or a planet that is massi...
Article
GW Ori is a hierarchical triple star system with a misaligned circumtriple protoplanetary disc. Recent ALMA observations have identified three dust rings with a prominent gap at $100\, \rm au$ and misalignments between each of the rings. A break in the gas disc may be driven either by the torque from the triple star system or a planet that is massi...
Article
Pollution of white dwarf atmospheres may be caused by asteroids that originate from the locations of secular and mean-motion resonances in planetary systems. Asteroids in these locations experience increased eccentricity, leading to tidal disruption by the white dwarf. We examine how the ν6 secular resonance shifts outwards into a previously stable...
Preprint
Pollution of white dwarf atmospheres may be caused by asteroids that originate from the locations of secular and mean-motion resonances in planetary systems. Asteroids in these locations experience increased eccentricity, leading to tidal disruption by the white dwarf. We examine how the $\nu_6$ secular resonance shifts outwards into a previously s...
Preprint
A disk around one component of a binary star system with sufficiently high inclination can undergo Kozai-Lidov (KL) oscillations during which the disk inclination and disk eccentricity are exchanged. Previous studies show that without a source of accretion, KL unstable disks exhibit damped oscillations, due to viscous dissipation, that leave the di...
Article
Full-text available
GW Ori is a hierarchical triple system with a rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and ¹² CO J = 2 − 1 molecular gas emission of the disk. For the first time, we identify three dust rings in the GW Ori disk at ∼46, 188, and 338 au, with estimated dust mass of 74...
Article
We investigate the formation mechanism for the observed nearly polar aligned (perpendicular to the binary orbital plane) debris ring around the eccentric orbit binary 99 Herculis. An initially inclined non-polar debris ring or disc will not remain flat and will not evolve to a polar configuration, due to the effects of differential nodal precession...
Article
Polluted white dwarfs are generally accreting terrestrial-like material that may originate from a debris belt like the asteroid belt in the Solar system. The fraction of white dwarfs that are polluted drops off significantly for white dwarfs with masses $M_{\rm WD}\gtrsim 0.8\, \rm M_\odot$. This implies that asteroid belts and planetary systems ar...
Preprint
GW Ori is a hierarchical triple system which has a rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12CO J=2-1 molecular gas emission of the disk. For the first time, we identify three dust rings in the disk at ~46, 188, and 338 AU, with estimated dust mass of ~70-250 E...
Preprint
We investigate the formation mechanism for the observed nearly polar aligned (perpendicular to the binary orbital plane) debris ring around the eccentric orbit binary 99 Herculis. An initially inclined nonpolar debris ring or disc will not remain flat and will not evolve to a polar configuration, due to the effects of differential nodal precession...
Preprint
Polluted white dwarfs are generally accreting terrestrial-like material that may originate from a debris belt like the asteroid belt in the solar system. The fraction of white dwarfs that are polluted drops off significantly for white dwarfs with masses $M_{\rm WD}\gtrsim 0.8\,\rm M_\odot$. This implies that asteroid belts and planetary systems aro...
Article
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 orbi...
Preprint
We analyse the evolution of a mildly inclined circumbinary disc that orbits an eccentric orbit binary by means of smoother particle hydrodynamic (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...
Article
The origin of fast radio bursts (FRBs) is still a mystery. One model proposed to interpret the only known repeating object, FRB 121102, is that the radio emission is generated from asteroids colliding with a highly magnetized neutron star (NS). With N–body simulations, we model a debris disc around a central star with an eccentric orbit intruding N...
Preprint
The origin of fast radio bursts (FRBs) is still a mystery. One model proposed to interpret the only known repeating object, FRB 121102, is that the radio emission is generated from asteroids colliding with a highly magnetized neutron star (NS). With N-body simulations, we model a debris disc around a central star with an eccentric orbit intruding N...
Article
Full-text available
Atmospheric nitrogen may be a necessary ingredient for the habitability of a planet as its presence helps to prevent water loss from a planet. The present-day nitrogen isotopic ratio, ¹⁵ N/ ¹⁴ N, in the Earth's atmosphere is a combination of the primitive Earth's ratio and the ratio that might have been delivered in comets and asteroids. Asteroids...
Preprint
Atmospheric nitrogen may be a necessary ingredient for the habitability of a planet since its presence helps to prevent water loss from a planet. The present day nitrogen isotopic ratio, $^{15}$N/$^{14}$N, in the Earth's atmosphere is a combination of the primitive Earth's ratio and the ratio that might have been delivered in comets and asteroids....
Preprint
In the past few decades, observations have revealed signatures of metals polluting the atmospheres of white dwarfs. The diffusion timescale for metals to sink from the atmosphere of a white dwarf is of the order of days for a hydrogen-dominated atmosphere. Thus, there must be a continuous supply of metal-rich material accreting onto these white dwa...
Article
With N-body simulations of a planetary system with an asteroid belt we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the $\nu_6$ secular resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the solar system is...

## Citations

... When full three-body systems are considered, angular momentum can be exchanged between the binary system and the circumbinary particle (Farago & Laskar 2010;). This creates a difference between the prograde and retrograde cases, and large angular momentum ratios = disk / b can lead to the formation of "crescent" librating orbits (Chen et al. 2019;Abod et al. 2022). Since we do not model the exchange of angular momentum between the disk and the binary, we expect the initially prograde and retrograde cases to be similar. ...
... Accretion rates in polar disks have been less studied. Smallwood et al. (2022) perform simulations of the HD 98800 system and find that binary accretion rates show no periodicity and are roughly constant in time for a polar disk with = 0.01. The high viscosity in these simulations means they do not form vortices, even during the passage of the outer AaAb binary. ...
... Multiple stellar systems are common in star-forming regions (Duchêne & Kraus 2013). Disks around triple star systems are also expected to be common (Tobin et al. 2016;Bate 2018), and there are several well-known examples including GG Tauri A (Di Folco et al. 2014;Keppler et al. 2020;Phuong et al. 2020a) and GW Ori (Bi et al. 2020;Kraus et al. 2020;Smallwood et al. 2021). A common feature of these disks is that they are tilted with respect to the orbital plane of the stars. ...
... Also helpful for pollution is when planets reside in multiple-planet systems, because otherwise perturbing minor bodies onto star-grazing orbits is challenging and may require asteroid reservoirs several orders of magnitude more massive than the Solar Systems' (Debes, Walsh, & Stark 2012). WD pollution due to secular chaos in multi-planet systems has been previously investigated in Smallwood et al. (2018Smallwood et al. ( , 2021 and O'Connor, Teyssandier, & Lai (2021). ...
... This list, which is not meant to be exhaustive, contains systems where dynamical processes -likely caused by nearby stars -are currently shaping planet-forming discs [e.g. [172][173][174][175][176][177][178][179][180][181][182][183][184][185][186]. As opposed to flybys, discs in multiple stellar systems are periodically perturbed by other stars, which may eventually lead to misaligned and compact planetary systems. ...
... This can lead to the creation of polar disks, where the disk is aligned perpendicular to the orbits of the binary stars. The stability of these two orientations has previously been confirmed using analytic theory and SPH numerical simulations (Martin & Lubow 2017Zanazzi & Lai 2018;Smallwood et al. 2019). ...
... Thus, given a planetesimal belt similar in mass to the present-day asteroid belt, secular chaos driven by planets larger than ∼ 10M⊕ beyond ∼ 10 au can sustain metal ac-cretion rates consistent with observations across most of the WD cooling sequence. The amount of mass that is expected to remain in a planetesimal belt after stellar evolution is uncertain, although some theoretical limits exist for the post-MS survival of planetesimals as a function of size, location, and stellar mass (e.g., Bonsor & Wyatt 2010;Veras et al. 2014;Martin et al. 2020). However, it is encouraging that the accretion rates produced by secular chaos broadly agree with observations given only the mass of the Solar System asteroid belt. ...
... Circumbinary discs have been observed with polar inclinations of 90 • to the binary orbit. HD98800 and V773 Tau B have polar circumbinary gas discs (Kennedy et al. 2019;Kenworthy et al. 2022) while 99 Her is a polar circumbinary debris disc (Kennedy et al. 2012;Smallwood et al. 2020). The formation and evolution of planets around binaries may be altered by the torque from the binary (e.g. ...
... Multiple stellar systems are common in star-forming regions (Duchêne & Kraus 2013). Disks around triple star systems are also expected to be common (Tobin et al. 2016;Bate 2018), and there are several well-known examples including GG Tauri A (Di Folco et al. 2014;Keppler et al. 2020;Phuong et al. 2020a) and GW Ori (Bi et al. 2020;Kraus et al. 2020;Smallwood et al. 2021). A common feature of these disks is that they are tilted with respect to the orbital plane of the stars. ...
... • Comet/asteroid interaction models: One suggested way of making FRBs is through interactions between comets or asteroids and a neutron star. The direct impact model (Bagchi, 2017;Dai, 2020;Dai et al., 2016;Dai and Zhong, 2020;Geng and Huang, 2015;Smallwood et al., 2019) invokes a gravitational energy budget ...