arXiv subjects

Jaehan Bae

Publications and source records attributed to Jaehan Bae.

At least 19 recordsLinked to original sources

arXiv2026

Mapping the WISPIT2 Planet-Hosting Cavity at Sub-Hill-Radius scales

We present new deep, very high angular resolution observations of the sub-mm continuum (19x13 mas) and 12CO (67x52 mas) emission from the disk surrounding the planet host WISPIT2. Our analysis reveals a clear gas gap carved by WISPIT 2b and an empty cavity within the orbit of WISPIT 2c. We also find a gaseous and optically thin dusty ring located between the orbits of the two planets. Channel maps show a pronounced change in the emission surface height of the disk, which transitions from flat within the cavity to strongly flared beyond the orbit of planet b, producing clear breaks in the velocity channels. A pronounced thunderbolt-shaped feature, identified as a kinematic planetary signature (KPS), is detected at the location of WISPIT 2b, in agreement with predictions from planet-disk interaction simulations. This constitutes the first system with a confirmed kinematic signature associated with a directly imaged planet. By mirroring opposite velocity-channel maps about the systemic velocity, we further investigate the KPS and identify spatially resolved excess emission in the vicinity of WISPIT 2b. We find that this emission is resolved across the full Hill sphere of the planet, significantly exceeding the expected extent of a circumplanetary disk. We therefore suggest that the observed emission arises from a combination of processes, including prominent planet-driven spiral wakes, localized heating induced by the planet and a circumplanetary disk. Although higher spectral resolution is required to disentangle these contributions, our observations demonstrate the potential to directly characterize the birth environment of forming massive planets at scales down to sub-Hill radius.

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arXiv2026

Dust Substructures and Line Perturbations driven by a Forming Planet in J16120

Hints of planet formation have been independently reported within the gap of the disc around 2MASS J16120668-301027 from millimetre continuum, infrared, and H-alpha observations. In this work, we present new evidence for ongoing planet formation based on Atacama Large Millimeter/submillimeter Array (ALMA) Band 7 observations, detecting 0.87 mm dust continuum emission together with 12CO (J=3-2) and 13CO (J=3-2) line emission. Visibility modelling of the continuum data reveals an inner disc and two dust rings peaking at 23 and 75 au. The continuum morphology is better reproduced by an eccentric disc model (e approximately 0.1) than by an axisymmetric disc. We further investigate the gas kinematics through modelling of the 12CO channel maps. The residual line-width map shows a localised increase in velocity dispersion at the position of a previously reported circumplanetary disc candidate (deprojected radius approximately 32 au, position angle approximately 170 degrees) and along its orbit. This signal is spatially coincident with kink-like features and a transition from sub-Keplerian to super-Keplerian velocities. In addition, the velocity residual map exhibits an arc-like structure extending outward from the planet candidate, while the gas kinematics, despite substantial uncertainties, is consistent with inflow towards the candidate's orbital radius. The observed increase in velocity dispersion agrees with predictions from planet-disc interaction simulations, which produce enhanced turbulence both at the planet location and along its orbital path. Taken together, the continuum morphology and gas kinematic signatures provide compelling new evidence for ongoing planet formation within the disc gap.

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arXiv2026

A Streamer Driving Misalignment in the Circumtriple Disk of GW Ori

GW Orionis is a triple stellar system with a disk featuring three misaligned dust rings. We present ALMA molecular line data of CO isotopologues, revealing a streamer feeding the disk in $^{12}$CO and $^{13}$CO. Through multi-pointing observations, we find the streamer extends to $\sim30''$ on-sky ($\sim12,000$~AU) and estimate a mass of 1.6 M$_{\rm Jup}$ using $^{13}$CO. Fitting the morphology and kinematics of the streamer, we estimate the mass infall timescale of 0.04 Myrs and a mass infall rate of $3.6\times10^{-8}$~M$_{\odot}$~yr$^{-1}$, approximately an order of magnitude lower than the stellar accretion rate. Our best-fit trajectory shows that the streamer meets the disk at the outermost dust ring and that the streamer's angular momentum vector is closely aligned with this outermost ring within $\approx3^\circ$, in contrast to the $\approx32^\circ$ misalignment with the innermost ring, suggesting the streamer is the likely cause of the misalignment. However, the total angular momentum of the streamer is smaller than that of GW Ori's disk; this, together with the low accretion rate, indicates that we are probably witnessing the end stages of infall. Total Power observations reveal bright emission connecting the streamer to the surrounding star-forming region, with a projected distance falling well within the Bondi-Hoyle radius, implying the streamer could have originated through Bondi-Hoyle accretion as GW Ori moves through its natal cloud. Together, these results suggest that GW Ori remains dynamically linked to its parental cloud through ongoing accretion, with the streamer serving as the likely driver of its misaligned disk structure.

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arXiv2026

The Circumbinary Disc of HD 34700A II. Analysis of a strong dust asymmetry

ALMA observations have shown that substructures are ubiquitous in protoplanetary discs. A sub-group, the transition discs, shows large cavities and rings in dust continuum. Among these, some present very high contrast asymmetries possibly due to the presence of vortices. HD 34700A is a binary system featuring a cavity, a ring, and multiple spiral arms detected in scattered light, a prominent crescent in the ALMA continuum and a complex gas morphology possibly connected with ongoing infall. We present new ALMA band 6 (1.3 mm) continuum images of the circumbinary disc around HD 34700A and compare them with two other systems showcasing high ($\gtrsim30$, measured as the peak-to-azimuthal-average ratio) contrast continuum asymmetries, IRS 48 and HD 142527. We aim to characterise the crescent morphology and discuss their possible origin. We perform visibility modelling of the new high resolution (0.''11x0.''09) ALMA band 6 continuum data of HD 34700A, together with improved visibility modelling of the other two targets. Our visibility model is in remarkable agreement with the HD 34700A data, featuring only localised residuals in the region of the disc corresponding to the tail of the asymmetry. We reproduce the double-peaked emission in HD 142527, and recover the crescent shape in IRS 48. We then run a hydrodynamic model of a vortex with different dust fluids, reproducing the general asymmetric crescent morphology observed in the HD 34700A and IRS 48 systems. With a combination of visibility, dust evolution and hydrodynamical models, we have constrained the morphology of the dust continuum emission of HD 34700A for the first time, and improved existing models for IRS 48 and HD 142527. The high azimuthal contrast of the asymmetries rules out the orbit clustering of eccentric cavities scenario, while the dust evolution models we consider suggest that the vortex scenario is a plausible option.

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arXiv2026

exoALMA XXII: A Two-dimensional Atlas of Deviations from Keplerian Disks

Protoplanetary disks are the birthplaces of planetary systems, and deviations from Keplerian rotation imprinted in disk gas kinematics serve as key tracers of physical processes and the presence of protoplanets within disks. Using the the CO (J=3-2) data from the exoALMA Large Program encompassing 15 disks, we constructed two-dimensional (2D) maps of centroid velocity, line width, and peak intensity, and extracted non-Keplerian deviations by subtracting smooth Keplerian models. This paper provides the first systematic and uniform overview of 2D gas substructures across the entire exoALMA sample. We find that all targets exhibit large-scale deviations from smooth Keplerian disks, displaying a variety of morphologies including spiral-like structures, arc- or ring-like features, and patterns indicative of variations in the emitting surface height. Non-axisymmetric spiral-arm features are detected or suggested in five disks (CQ Tau, MWC 758, HD 135344B, HD 34282, and SY Cha), and are preferentially found in Herbig Ae/Fe systems. In contrast, some other sources (J1852, PDS 66, and V4046 Sgr), despite exhibiting noticeable deviations, appear to be dynamically quieter. This 2D atlas suggests that kinematic substructures are ubiquitous in large ($\gtrsim$ 100 au) protoplanetary disks with ages of a few million years, based on the observations obtained with sufficient sensitivity at moderate-to-high spatial resolution of $\sim$20 au and high velocity resolution of $\sim$0.1 km s$^{-1}$.

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arXiv2026

exoALMA. XXIV. Formaldehyde Emission in Protoplanetary Disks of exoALMA Compared with Their Properties and Dynamical State

The presence of asymmetries and substructures in protoplanetary disks, revealed by both dust and gas emission, highlights the potential interplay and the broader connection between chemistry and dynamics in disk evolution. We explore multiple relationships using the nonparametric Kendall-$\tau$ correlation to examine formaldehyde (H$_2$CO) emission with relation to stellar and disk properties for a subset of disks from the exoALMA sample. We also retrieve the H$_2$CO column density and excitation temperature using four transitions, measured in radial bins of 100 au, and quantify the level of asymmetry in the resolved peak intensity of the H$_2$CO emission. From our correlation analysis, we find no correlations with sufficient statistical significance. However, we identify tentative relationships that can be tested with larger samples. In particular, we report a proposed correlation ($2.1\sigma$) between stellar effective temperature and the formaldehyde excitation conditions, suggesting that, to first order, the central star dominates the nature of the H$_2$CO emission over possible dynamical asymmetries traced by dust. Although a correlation with the stellar luminosity was also expected, a larger sample is required to confirm or refute this trend. A possible correlation with spectral type, together with the broad range of H$_2$CO excitation temperatures within the inner 100 au of the studied disks, hint at possible multiple chemical formation pathways for H$_2$CO, including both gas-phase reactions and ice-surface chemistry on dust grains.

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arXiv2026

exoALMA XXI: The Morphology and Dynamics of Vertical Flows

Vertical gas flows, such as winds and meridional circulations, are natural outcomes of protoplanetary disk processes and play a critical role in the earliest stages of planet formation. We analyze vertical gas motions in 14 disks as part of the exoALMA Large Program, focusing on the 12CO J=3-2 and 13CO J=3-2 emission lines. Using discminer to model the Keplerian velocity field, we extract line-of-sight velocity residuals and measure the radial and vertical components of the gas motion. Vertical motions are detected in most disks. Two types of patterns emerge: (1) oscillatory up/down flows, likely linked to instabilities, and (2) transitions from downward to upward motions that we interpret as the base of a disk wind. In most cases, the velocity amplitudes are of a few tens of m/s. Two disks, however, MWC758 and CQ Tau, show two spiral velocity features in their residual maps, red- and blue-shifted, which we interpret as vertical velocities reaching up to 350 m/s (0.7 Cs), consistent with gas motion in eccentric disks. Fast upward motions (up to 500 m/s; 1.8 Cs) is also detected in the outer disk of MWC758. Synthetic observations from (magneto)hydrodynamic simulations validate the reliability of our method. Although strong molecular winds appear to be relatively rare in 12CO and 13CO, our study shows that, when traced by deep high spectral resolution line data, protoplanetary disks exhibit ubiquitous vertical flows. However, their overall velocity structure is highly complex, preventing to identify a coherent, dominant physical mechanism driving the vertical motions across all disks, thus requiring further theoretical investigation.

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arXiv2026

exoALMA XXIII. Estimating Disk and Planet Properties from Dust Morphologies with DBNets2.0

The exoALMA large program provided an unprecedented view of the morphology and kinematics of 15 circumstellar disks, offering a biased but homogenous and well-characterized sample for population-level analysis. Continuum observations revealed numerous dust substructures, known to be potential signatures of embedded planets. We analyze the observed dust morphologies with the simulation-based inference tool DBNets2.0, assuming these are due to embedded planets at fixed locations, to infer the system properties. We estimate the putative planet mass, the disk $\alpha$-viscosity, scale-height, and dust Stokes number that would reproduce 19 substructures in 13 of the 15 exoALMA disks. We compare our results with literature estimates derived with different methods, and find good agreement in most cases. We further explore the implications of the inferred disk properties for accretion, showing that for the Herbig stars in our sample, the implied viscous accretion timescales are too long to account for their observed stellar accretion rates. Regarding planet migration, our results favor inward migration, with only three putative planets expected to migrate outward. Finally, we check for correlations of the inferred disk and planet properties with the disks' gas-to-dust mass ratio, non-axisymmetry index, and masses of the gas, dust, and host stars, finding no remarkable trend.

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arXiv2026

exoALMA XX: Tomographic Detection of Embedded Planets in Protoplanetary Disks

The exoALMA Large Program has revealed a wealth of substructures in the dust and molecular line emission of several protoplanetary discs, suggesting that planet formation may unfold within highly dynamic environments. Using synthetic observations of planet-disc interactions and disc instabilities, we demonstrate how the origin of these substructures can be investigated through a tomographic study of molecular lines, extending the scope of the analysis beyond line-centroid kinematics alone. Our results indicate that with only a few hours of ALMA integration at moderate angular resolution ($0.15''-0.30''$), it is possible to identify the key signatures driven by planets more massive than 0.1% of the stellar mass. These signatures manifest not only as deviations from Keplerian motion but also as localized line broadening, enabling accurate constraints on the orbital radius and azimuthal location of the planets. We further show that a diagnostic based on line skewness in spectrally resolved observations can help distinguish between planetary and instability-driven signatures, owing to the distinct degrees of velocity coherence associated with each mechanism. Finally, we apply this tomographic analysis to exoALMA CO line data for the discs of HD 135344B and MWC 758. In HD 135344B, we identify strongly localized velocity and line-width perturbations, suggesting the possibility of three massive planets embedded in the disc: one at $R=95$ au, exterior to the continuum substructures, and two within dust gaps at $R=41$ au and $R=73$ au. For MWC 758, the dominance of vertical-velocity spirals over localized signatures is consistent with predictions from models of moderate disc eccentricities or warps, potentially induced by a substellar companion in the inner regions of the system.

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arXiv2026

A Protoplanet Candidate in the PDS 66 Disk Indicated by Silicon Sulfide Isotopologues

Despite observational progress in planet formation, the stage in which planetesimals grow into planets remains poorly understood. During this phase, protoplanets may develop gaseous envelopes that are warmer than the surrounding disk gas, potentially providing observable signatures through molecules otherwise depleted in cold regions. In this Letter, we report the detection of the silicon sulfide isotopologues ${\rm ^{28}SiS}\ J{=}16{-}15$ and ${\rm ^{30}SiS}\ J{=}18{-}17$ in the protoplanetary disk around PDS 66 (MP Mus) at a significance of ${\sim}5{-}6\sigma$, using the Atacama Large Millimeter/submillimeter Array. These constitute the second and first detections of $\rm ^{28}SiS$ and $\rm ^{30}SiS$ in a protoplanetary disk, respectively. The emission appears as a compact source at $r \simeq 60$ au in the southwestern region of the disk, unresolved with a ${\sim}0.\!\!^{\prime\prime}5$ beam, and shows a velocity consistent with Keplerian rotation, suggesting a protoplanetary origin. By modeling the line fluxes, we constrain the emitting radius to ${\sim}0.5{-}4$ au and estimate an SiS mass of $10^{22}{-}10^{23}$ g, corresponding to at least ${\sim}10\%$ of the silicon contained in local dust grains. Because complete sublimation of a substantial fraction of dust grains by local processes is difficult to achieve, this result instead implies an accumulation of silicon from a larger region. We propose that a circumplanetary envelope surrounding a low-mass protoplanet, where pebble accretion and subsequent sublimation of grains may enhance gaseus silicon abundance with respect to observable dust grains around it, can account for the observed characteristics.

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arXiv2026

exoALMA XIX: Confirmation of Non-thermal Line Broadening in the DM Tau Protoplanetary Disk

Turbulence is expected to transport angular momentum and drive mass accretion in protoplanetary disks. One way to directly measure turbulent motion in disks is through molecular line broadening. DM Tau is one of only a few disks with claimed detection of nonthermal line broadening of 0.25cs-0.33cs, where cs is the sound speed. Using the radiative transfer code mcfost within a Bayesian inference framework that evaluates over five million disk models to efficiently sample the parameter space, we fit high-resolution (0.15", 28 m s-1) 12CO J = 3-2 observations of DM Tau from the exoALMA Large Program. This approach enables us to simultaneously constrain the disk structure and kinematics, revealing a significant nonthermal contribution to the line width of ~0.4cs, inconsistent with purely thermal motions. Using the CO-based disk structure as a starting point, we reproduce the CS J = 7-6 emission well, demonstrating that the CS (which is more sensitive to nonthermal motions than CO) agrees with the turbulence inferred from the CO fit. Establishing a well-constrained background disk model further allows us to identify residual structures in the moment maps that deviate from the expected emission, revealing localized perturbations that may trace forming planets. This framework provides a powerful general approach for extracting disk structure and nonthermal broadening directly from molecular line data and can be applied to other disks with high-quality observations.

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arXiv2026

Physical and Chemical Characterization of GY 91's Multi-ringed Protostellar Disk with ALMA

GY 91, commonly categorized as a Class I young stellar object, is notable for disk dust substructures that have been hypothesized to trace early planet formation. Using the ALMA 12-m and ACA arrays, we present new Band 7 dust continuum and molecular line observations of GY 91 at an angular resolution of (~40 au). We report detections of CS $J=6-5$, N$_2$H$^+$ $J=3-2$, C$^{18}$O $J=3-2$, H$_2$CS $J_{K_a, K_c} = 8_{1,7}-7_{1,6}$, H$_2$CO $J_{K_a, K_c} = 4_{0,4}-3_{0,3}$, and H$_2$CO $J_{K_a, K_c} = 4_{2,3}-3_{2,2}$, as well as a tentative detection of $^{13}$C$^{18}$O $J=3-2$. We observe azimuthal asymmetry in CS and H$_2$CS emission, as well as radially structured H$_2$CO $4_{0,4}-3_{0,3}$ emission outside the dust continuum. C$^{18}$O and H$_2$CO 4$_{0,4}-3_{0,3}$ show significant cloud contamination, while CS and N$_2$H$^+$ are good tracers of Keplerian rotation originating from the disk. Envelope emission does not appear to contribute significantly either to the continuum or molecular line observations. GY 91's chemical properties appear in large part to resemble those of Class II disks, although observations of additional molecular probes should be obtained for a fuller comparison. With CS, we estimated a dynamical stellar mass of 0.58 $M_\odot$, which is higher than previous estimates from stellar evolutionary models (0.25 $M_\odot$). Using both radiative transfer modeling of the dust continuum and comparison of the C$^{18}$O and N$_2$H$^+$ fluxes to literature thermochemical models, we estimate a disk mass of $\sim0.01$ $M_\odot$.

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arXiv2026

A 2 au resolution view by ALMA of the planet-hosting WISPIT 2 disk

We present deep, high spatial resolution interferometric observations of 0.88 mm continuum emission from the TYC 5709-354-1 system, hereafter WISPIT 2, obtained with the goal of detecting circumplanetary emission in the vicinity of the newly discovered WISPIT 2b planet. Observations with the most extended baseline configuration offered by ALMA, achieving an angular resolution of $25 \times 17$ mas ($3.3 \times 2.2$ au), revealed a single, narrow ring with a deprojected radius of 144.4 au and width of 7.2 au, and no evidence of circumplanetary emission within the cavity. Injection and recovery tests demonstrate that these observations can rule out point-like emission at the location of WISPIT 2b brighter than $\approx 45$ $\mu$Jy at the $3\sigma$ level. While these data can rule out PDS 70c like circumplanetary emission, the upper limit is consistent with empirical mass-flux relationships extrapolated from the stellar regime. Visibility modeling of the continuum ring confirms that WISPIT 2b lies significantly interior to the mm dust ring, raising doubts about the ability of WISPIT 2b to be the only driver of the dust structure. Possible solutions include either another lower mass companion, residing between WISPIT 2b and the cavity edge, likely in the gap seen by SPHERE at $\sim130$ au, or that WISPIT 2b is either substantially more massive than IR-photometry based estimates ($\sim15$ $M_{\rm Jup}$) or on a moderately eccentric orbit. The combination of observations sensitive to the gas and dust distributions on larger spatial scales and dedicated hydrodynamical modeling will help differentiate between scenarios.

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arXiv2026

Circumplanetary Disk Candidate in the Disk of HD 163296 Traced by Localized Emission from Simple Organics

Atacama Large Millimeter/submillimeter Array observations suggest that the disc of HD 163296 is being actively shaped by embedded, yet unseen protoplanets, as indicated by numerous gas and dust substructures consistent with planet-disc interaction models. We report the first detection of simple organic molecules, HCN and C2H, tracing a candidate circumplanetary disc (CPD) in the HD 163296 system, located at an orbital radius of $R=88\pm7$ au and azimuth $\phi=46\pm3^\circ$ (or $R=0.75''$, $\rm{{PA}}=350^\circ$ in projected sky coordinates), and originating near the midplane of the circumstellar disc. The signature is localised but spectrally resolved, and it overlaps with a previously reported planet candidate, P94, identified through kinematic perturbations traced by CO lines. We propose a scenario in which the observed chemical anomalies arise from increased heating driven by the forming planet and ongoing accretion through its CPD, facilitating the thermal desorption of species that would otherwise remain frozen out in the disc midplane, and potentially triggering the activation barriers of chemical reactions that lead to enhanced molecular production. Based on a first-order dynamical analysis of the HCN spectrum from the CPD--isolated with a 7$\sigma$ significance--we infer an upper limit on the planet mass of 1.8 $M_{\rm Jup}$, consistent with predictions from CO kinematics and constraints from direct imaging studies. By comparing the CPD sizes derived from our models with theoretical expectations where the CPD radius corresponds to roughly one-third of the planet's Hill radius, we favor CPD gas temperatures $T > 150$ K, planet masses $M_{\rm p} < 1.0$ $M_{\rm Jup}$, and CPD radii $R_{\rm CPD} < 2$ au.

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arXiv2026

Tracing Pebble Drift History in Two Protoplanetary Disks with CO Enhancement

Pebble drift is an important mechanism for supplying the materials needed to build planets in the inner region of protoplanetary disks. Thus, constraining pebble drift's timescales and mass flux is essential to understanding planet formation history. Current pebble drift models suggest pebble fluxes can be constrained from the enhancement of gaseous volatile abundances when icy pebbles sublimate after drifting across key snowlines. In this work, we present ALMA observations of spatially resolved $^{13}$C$^{18}$O J=2-1 line emission inside the midplane CO snowline of the HD 163296 and MWC 480 protoplanetary disks. We use radiative transfer and thermochemical models to constrain the spatial distribution of CO gas column density. We find that both disks display centrally peaked CO abundance enhancement of up to ten times of ISM abundance levels. For HD 163296 and MWC 480, the inferred enhancements require 250-350 and 480-660 Earth Masses of pebbles to have drifted across their CO snowlines, respectively. These ranges fall within cumulative pebble mass flux ranges to grow gas giants in the interior to the CO snowline. The centrally peaked CO enhancement is unexpected in current pebble drift models, which predict CO enhancement peaks at the CO snowline or is uniform inside the snowline. We propose two hypotheses to explain the centrally-peaked CO enhancement, including a large CO desorption distance and CO trapped in water ice. By testing both hypotheses with the 1D gas and dust evolution code chemcomp, we find that volatile trapping (about 30\%) best reproduces the centrally peaked CO enhancement observed.

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arXiv2025

A Submillimeter Survey of CS Excitation in Protoplanetary Disks: Evidence of X-ray-Driven Sulfur Chemistry

The sulfur chemistry in protoplanetary disks influences the properties of nascent planets, including potential habitability. Although the inventory of sulfur molecules in disks has gradually increased over the last decade, CS is still the most commonly-observed sulfur-bearing species and it is expected to be the dominant gas-phase sulfur carrier beyond the water snowline. Despite this, few dedicated multi-line observations exist, and thus the typical disk CS chemistry is not well constrained. Moreover, it is unclear how that chemistry - and in turn, the bulk volatile sulfur reservoir - varies with stellar and disk properties. Here, we present the largest survey of CS to date, combining both new and archival observations from ALMA, SMA, and NOEMA of 12 planet-forming disks, covering a range of stellar spectral types and dust morphologies. Using these data, we derived disk-integrated CS gas excitation conditions in each source. Overall, CS chemistry appears similar across our sample with rotational temperatures of ${\approx}$10-40 K and column densities between 10$^{12}$-10$^{13}$ cm$^{-2}$. CS column densities do not show strong trends with most source properties, which broadly suggests that CS chemistry is not highly sensitive to disk structure or stellar characteristics. We do, however, identify a positive correlation between stellar X-ray luminosity and CS column density, which indicates that the dominant CS formation pathway is likely via ion-neutral reactions in the upper disk layers, where X-ray-enhanced S$^+$ and C$^+$ drive abundant CS production. Thus, using CS as a tracer of gas-phase sulfur abundance requires a nuanced approach that accounts for its emitting region and dependence on X-ray luminosity.

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arXiv2025

On The Orbital Evolution of Multiple Wide Super-Jupiters: How Disk Migration and Dispersal Shape the Stability of The PDS 70 System

Direct imaging has revealed exoplanet systems hosting multiple wide-orbit Super-Jupiters, where planet-planet interactions can shape their long-term dynamical evolution. These strong perturbations may lead to orbital instability, raising questions about the long-term survival of such systems. Shortly after formation, planet-disk interactions can shepherd planets into mean-motion resonances, which may promote long-term stability as seen in HR 8799. However, early-stage processes such as disk photoevaporation and viscosity can influence these outcomes. The $\sim$5 Myr-old PDS 70 system offers a unique laboratory to investigate these processes: its two massive ($>$4 $M_{Jup}$), wide-orbit ($>$20 AU) giants are still embedded in their natal disk. We perform 2D hydrodynamic simulations of the system, allowing the disk to disperse via photoevaporation. Once the disk dissipates, we continue to track the planets' orbital evolution over Gyr timescales using N-body simulations. We find that the system is likely to remain stable for $>$ 1 Gyr. To assess the importance of disk-driven evolution, we compare these results with disk-free N-body simulations using orbital parameters constrained by orbit fits that include recent relative astrometry and radial velocities from the literature. In this case, we find that only $\lesssim 4\%$ of posterior is stable for 100 Myr, highlighting the importance of considering disk-driven evolution for long-term dynamics stability of exoplanetary systems. We also simulate two three-planet configurations including the proposed inner candidate "PDS 70 d", finding that a higher photoevaporation leads the system to become unstable in $<$ 10 Myr.

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arXiv2025

Enhanced Pebble Drift Across Planet-Opened Gaps in Windy Protoplanetary Disks

When a giant planet forms in a protoplanetary disks, it carves a gap around its orbit separating the disk into two parts: inner disk and outer disk. Traditional disk accretion models, which assume material transport is driven by viscosity, reveal that the planet-induced gap acts like a filter which blocks large dust grains from flowing into the inner disk. However, there is growing evidence that material transport may be driven by magnetically-driven winds instead. By carrying out a suite of two-dimensional multi-fluid hydrodynamic simulations where wind is implemented with a parameterized model, we explored how dust filtration efficiency and the size of dust grains filtered change in disks where gas accretion is dominated by magnetically-driven winds. We found that the inward gas flow driven by the wind can enable dust to overcome the pressure bump at the outer gap edge and penetrate the planet-induced gap. The maximum size of dust grains capable of penetrating the gap increasing with the wind strength. Notably, we found that when wind is strong (mass loss rate = 1e-7 M_sun/yr), mm-sized grains can penetrate the gap opened by a multi-Jovian-mass planet. Our results suggest that magnetically driven winds can significantly enhance pebble drift and impact planet formation in the inner protoplanetary disk.

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