arXiv subjects

JT Laune

Publications and source records attributed to JT Laune.

4 recordsLinked to original sources

arXiv2025

Resonance Capture of a Test Particle by an Eccentric Planet in the Presence of Externally-Driven Apsidal Precession

Planets undergoing convergent migration can be captured into mean-motion resonance (MMR), in which the planets' periods are related by integer ratios. The dynamics of MMR are typically considered in isolation, including only the forces between the planets and with the central star. However, the planets are often subjected to external forces that induce apsidal precessions, which may split the MMR into two sub-resonances and give rise to chaotic motion due to resonance overlap. In this study, we investigate how such externally induced differential apsidal precession affects capture into first-order $j:j+1$ MMRs. We study the restricted three-body problem for a test particle outside of an eccentric planet, with the planet undergoing outward migration. We find that capture can be sensitive to the differential apsidal precession, even when the precession rate is much smaller than the resonance overlap criterion. We identify two critical precession frequencies -- related to resonance overlap and secular apsidal resonance -- around which capture is disrupted even for very small planet eccentricity. Our results may help clarify the capture process of resonant trans-Neptunian objects by outward-migrating Neptune in early Solar System.

astro-ph.EP↗

arXiv2024

Migration of Accreting Planets and Black Holes in Disks

Nascent planets are thought to lose angular momentum (AM) to the gaseous protoplanetary disk via gravitational interactions, leading to inward migration. A similar migration process also applies to stellar-mass black holes (BHs) embedded in the disks of active galactic nuclei. However, AM exchange via accretion onto the planet/BH may strongly influence the migration torque. In this study, we perform 2D global hydrodynamic simulations of an accreting planet/BH embedded in a disk, where AM exchange between the planet/BH and disk via gravity, accretion, pressure, and viscosity are considered. When accretion is turned off, we recover the linear estimate for Type I migration torque. However, for the two planet masses we investigated with our accreting simulations, we find outward migration due to the positive AM deposited onto the accreting body by the disk gas. Our simulations achieve the global steady state for the transport of mass and AM: The mass and AM fluxes are constant across the disk except for jumps ($\Delta\dot M$ and $\Delta\dot J$) at the planet's location, and the jumps match the accretion rate and torque on the planet. Our findings suggest that caution is needed when applying the standard results of disk migration to accreting planets and BHs.

astro-ph.EP↗

arXiv2022

Apsidal Alignment and Anti-Alignment of Planets in Mean-Motion Resonance: Disk-Driven Migration and Eccentricity Driving

Planets migrating in their natal discs can be captured into mean-motion resonance (MMR), in which the planets' periods are related by integer ratios. Recent observations indicate that planets in MMR can be either apsidally aligned or anti-aligned. How these different configurations arise is unclear. In this paper, we study the MMR capture process of migrating planets, focusing on the property of the apsidal angles of the captured planets. We show that the standard picture of MMR capture, in which the planets undergo convergent migration and experience eccentricity damping due to planet-disc interactions, always leads to apsidal anti-alignment of the captured planets. However, when the planets experience eccentricity driving from the disc, apsidally aligned configuration in MMR can be produced. In this configuration, both planets' resonance angles circulate, but a "mixed" resonance angle librates and traps the planets near the nominal resonance location. The MMR capture process in the presence of disc eccentricity driving is generally complex and irregular, and can lead to various outcomes, including apsidal alignment and anti-alignment, as well as the disruption of the resonance. We suggest that the two resonant planets in the K2-19 system, with their moderate eccentricities and aligned apsides, have experienced eccentricity driving from their natal disc in the past.

astro-ph.EP↗

arXiv2019

Ring Morphology with Dust Coagulation in Protoplanetary Disks

Tidal interactions between the embedded planets and their surrounding protoplanetary disks are often postulated to produce the observed complex dust substructures, including rings, gaps, and asymmetries. In this Letter, we explore the consequences of dust coagulation on the dust dynamics and ring morphology. Coagulation of dust grains leads to dust size growth which, under typical disk conditions, produces faster radial drifts, potentially threatening the dust ring formation. Utilizing 2D hydrodynamical simulations of protoplanetary disks which include a full treatment of dust coagulation, we find that if the planet does not open a gap quickly enough, the formation of an inner ring is impeded due to dust coagulation and subsequent radial drift. Furthermore, we find that a "buildup" of sub-mm sized grains often appears in the dust emission at the outer edge of the dust disk.

astro-ph.EP↗