arXiv subjects

Miguel Vioque

Publications and source records attributed to Miguel Vioque.

At least 37 records · Page 2Linked to original sources

arXiv2026

Planet-forming disks and their environment across regions and time from the full NIR census

The evolution of planet-forming disks and the processes of planet formation influence each other, and both of them are possibly impacted by the local environment. Extensive high-resolution imagery of disks across space and time is the best tool for determining their evolution. We compiled a comprehensive list of disk-bearing young stars with near-IR high-contrast images available. The sample sums up to 268 sources, including 51 targets with no prior publications, which makes this study the largest of its kind and the most extensive release of IR disk images to date. Our census reveals very diverse disk and ambient morphologies. Disks in Lupus are bright, in Chamaeleon are faint, in Corona Australis and Taurus are frequently surrounded by ambient emission. Disks experience an abrupt increase in IR brightness between 2 Myr and 5 Myr. The earliest IR disk cavities around single stars arise after 2-3 Myr explaining why are young disks faint in the near-IR, and determining which disks can live longer. Well-known, high-longevity disks (>8 Myr) are always bright. Ambient material is detected in more than 20% of young sources but the fraction drops with time. We find a clear correspondence for the presence of ambient material with the stellar variability, near-IR excess, and mass accretion rate as well as, in turn, with spirals and shadows in disks. Half of the disks with ambient material show spirals while none of them show rings. We therefore propose that the spirals and the disk warps responsible for shadows are generally induced by late infall from the medium, and that this also affects the stellar accretion. The emerging picture proves the fundamental role of the environment for the disk evolution and planet formation.

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arXiv2026

Survival of Protoplanetary Disks in Upper Scorpius from Population Synthesis Models with External Photoevaporation

We present population synthesis models of viscous protoplanetary disks subject to mild external far-ultraviolet (FUV) radiation fields ($F_{\rm UV}=1\text{-}100\,$G$_0$). Our simulations focus on gas disk evolution, exploring stellar masses drawn from an Initial Mass Function and a range of initial disk conditions. We quantify the fraction of surviving disks across $10\,\mathrm{Myr}$ of evolution, track the evolution of gas disk mass and size, and compare our results with observations of protoplanetary disks in the Upper Scorpius region, including the ten targets studied by the AGE-PRO ALMA Large Program. We find that models combining viscous evolution with external photoevaporation yield disk lifetimes of $3\text{-}7\,\mathrm{Myr}$, consistent with observed dispersal timescales, particularly for $10^{-4} \leq α\leq 10^{-2}$. Low-mass stars ($0.1\,$M$_\odot$) are more susceptible to disk dispersal due to their weaker gravitational binding, with their fraction among all surviving disks dropping from $76\%$ at birth to $51\%$ by $10\,\mathrm{Myr}$. The majority of the long-lived disks are those with low viscosity $α< 10^{-3.5}$ and initial characteristic radius $R_c < 125\,\mathrm{AU}$, while the initial disk-to-star mass ratio does not play an important role. The median gas disk mass and radius of the surviving disks exhibit a sharp decline in the first $0.2\,\mathrm{Myr}$ of evolution, followed by a slight increase that reflects survivorship bias. We also explore correlations between gas disk mass and size vs. stellar mass and FUV strength. Our findings highlight the critical role of external photoevaporation in shaping disk populations even at moderate levels of FUV radiation fields.

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arXiv2026

Protoplanetary disk cavities with JWST-MIRI: a dichotomy in molecular emission

The evolution of planet-forming regions in protoplanetary disks is of fundamental importance to understanding planet formation. Disks with a central deficit in dust emission, a "cavity", have long attracted interest as potential evidence for advanced disk clearing by protoplanets and/or winds. Before JWST, infrared spectra showed that these disks typically lack the strong molecular emission observed in full disks. In this work, we combine a sample of 12 disks with millimeter cavities of a range of sizes ($\sim2$-70 au) and different levels of millimeter and infrared continuum deficits. We analyze their molecular spectra as observed with MIRI on JWST, homogeneously reduced with the new JDISCS pipeline. This analysis demonstrates a stark dichotomy in molecular emission where "molecule-rich" (MR) cavities follow global trends between water, CO, and OH luminosity and accretion luminosity as in full disks, while "molecule-poor" (MP) cavities are significantly sub-luminous in all molecules except sometimes OH. Disk cavities generally show sub-luminous organic emission, higher OH/H$_2$O ratios, and suggest a lower water column density. The sub-thermal excitation of CO and water vibrational lines suggests a decreased gas density in the emitting layer in all cavities, supporting model expectations for C$_2$H$_2$ photodissociation. We discover a bifurcation in infrared index (lower in MR cavities) suggesting that the molecular dichotomy is linked to residual $μ$m-size dust within millimeter disk cavities. Put together, these results suggest a feedback process between dust depletion, gas density decrease, and molecule dissociation. Disk cavities may have a common evolutionary sequence where MR switch into MP over time.

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arXiv2025

The mass distribution of clumpy accretion onto the nearby young star TW Hya

The proliferation of high time-resolution and decades-long monitoring of classical T Tauri stars provides a vast opportunity to test the variability of the star-disk connections. However, most monitoring surveys use single broad-band filters, which makes the conversion of photometric variability into accretion rate difficult. In this study, we analyze accretion bursts onto the nearby young star TW Hya over short (hours, days) and long (months, years) timescales by calibrating TESS and ASAS-SN $g$-band photometry to accretion rates with simultaneous spectroscopy. The high cadence TESS light curve shows bursts of accretion in clumps with masses from a sensitivity limit of $\sim10^{-13}$~M$_\odot$ up to $3\times 10^{-11}$\,M$_\odot$. The average burst duration of 1.8 days is longer than a simple estimate of the thermal response timescale, supporting the interpretation that the photometric variability probes the instantaneous accretion rate. The reset timescale of 1.2--2 days derived from the structure function and previously reported quasi-periods of 3.5--4 days are consistent with bursts that may be related to the different rotation between the stellar magnetosphere and inner disk or with azimuthal asymmetries in the inner disk. The near-daily ASAS-SN light curve across 8 years reveals some seasonal changes in brightness with a standard deviation of $\sim 0.13$ mag, about half of the scatter seen on short timescales. This study demonstrates the importance of coordinating contemporaneous multi-epoch spectroscopy with time domain surveys to interpret light curves of young stars.

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arXiv2025

Resolving the large exoKuiper belt of the HD 126062 debris disc and extended gas emission in its vicinity

Intermediate-mass stars (1-3 Msun) host some of the brightest and best-studied debris discs. This stellar class is also the most frequent host of molecular gas in systems older than typical protoplanetary disc lifetimes, and the most likely to host detected giant planets in radial-velocity surveys. The debris discs of intermediate-mass stars have therefore become fertile ground for studying disc-planet interactions. In this work, we present the first ALMA observations toward the A-type star HD 126062, located in Upper Centaurus Lupus / Lower Centaurus Crux, with the aim of characterising its debris disc. We probed the thermal continuum emission using observations at 1.3 mm, analysed through image reconstruction under different visibility-weighting regimes and parametric model fitting to the observed visibilities. The setup also covered the frequency of the 12CO(2-1) line, allowing imaging of gas near the system. We detected dust continuum emission from an exo-Kuiper belt around HD 126062. Modelled as a Gaussian ring, the visibilities are consistent with a radial separation R = 2.01'' (+0.04, -0.05), equivalent to ~270 (+5, -4) au, and a full width at half maximum DeltaR = 0.71'' +- 0.09 (95 +- 12 au). The continuum emission appears nearly face-on, with inclination <=17 deg. 12CO(2-1) emission is detected in the vicinity of the debris disc, with most of it located external to the exo-Kuiper belt. The exo-Kuiper belt characterised here is among the largest yet detected and agrees with previous predictions of the dust distribution based on spectral energy distribution fitting. The morphology and velocity offset relative to the systemic velocity suggest that the gas is not associated with the star or disc, but likely originates from a diffuse cloud in the nearby galaxy.

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arXiv2025

Observational Constraints on Evolution of Dust Disc Properties in Upper Scorpius

Protoplanetary discs in the Upper Scorpius star-forming region are excellent laboratories to investigate late stages of planet formation. In this work, we analyse the morphology of the dust continuum emission of 121 discs from an ALMA Band 7 survey of the Upper Scorpius region. This analysis is done in the visibility plane, to measure the flux, geometry and characterise potential structures. We compare the results with state-of-the art gas and dust evolution models that include external photoevaporation, with mild values of the $F_{\rm{UV}}$ of 1-40$G_0$. From the visibility analysis, 52 of the 121 discs are resolved (43%). From the resolved discs, 24 discs have structures and 28 remain as smooth discs at the mean resolution scale of $\sim$0.1$^{\prime \prime}$ (~14au). Our results show no significant dust disc size evolution of the surviving discs in UpperSco when compared to discs in younger star-forming regions, such as Lupus. We find a strong, steeper-than-previously-reported correlation between dust disc size and disc millimeter continuum luminosity, in agreement with drift-dominated dust evolution models. We also find positive correlations between the dust disc mass vs. stellar mass and dust disc size vs. stellar mass. The slope of the dust disc size vs. stellar mass relationship is steeper compared to younger star forming regions. Additionally, we observe no significant correlation between dust disc properties and the environmental $F_{\rm{UV}}$, consistent with models predicting that dust disc properties are primarily shaped by drift and dust traps. Our models predict that gas disc masses and sizes should be highly affected by the moderate $F_{\rm{UV}}$ values that Upper Scorpius discs experience in contrast to the dust, highlighting the need for deeper and higher-resolution gas observations of these discs exposed to mild external photoevaporation.

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arXiv2025

Probing dust and grain growth in the optically thick circumbinary ring of V892 Tau

A considerable proportion of young stars belong to multiple star systems. Constraining the planet formation processes in multiple stellar systems is then key to understand the global exoplanet population. This study focuses on investigating the dust reservoir within the triple system V892 Tau. Our objective is to establish constraints on the properties and characteristics of the dust present in the system's circumbinary ring. Based on archival ALMA and VLA data from 0.9 mm to 9.8 mm, we present a multi-wavelength analysis of the ring of V892 Tau. We first studied the spatial variation of the spectral index, before employing 3D full radiative transfer calculations to constrain the ring's geometry and the radial dependence of the dust grain properties. Spectral indices are consistent with non-dust emission in the vicinity of the central binary, and with dust emission in the ring likely remaining optically thick up to 3.0 mm. Our radiative transfer analysis supports these interpretations, yielding a model that reproduces the observed intensities within the 1-sigma uncertainties across all wavelengths. The resulting dust surface density and temperature profiles both decrease with increasing radius, and are in agreement with values reported in the literature. Maximum grain sizes are constrained to 0.2 cm, with a size distribution power-law index -3.5. These results imply that the dust grain fragmentation velocity does not exceed 8 m/s. Whilst our results suggest dust trapping at the cavity edge, they also suggest that tidal perturbations triggered by the central binary limit grain growth within the ring. This highlights the need to further constrain planet formation efficiency in multiple stellar systems, a goal that may be advanced by applying the methodology of this work to a wider sample of systems.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): II. Dust and Gas Disk Properties in the Ophiuchus Star-forming Region

The ALMA survey of Gas Evolution in PROtoplanetary disks (AGE-PRO) Large Program aims to trace the evolution of gas disk mass and size throughout the lifetime of protoplanetary disks. This paper presents Band-6 ALMA observations of 10 embedded (Class I and Flat Spectrum) sources in the Ophiuchus molecular cloud, with spectral types ranging from M3 to K6 stars, which serve as the evolutionary starting point in the AGE-PRO sample. While we find 4 nearly edge on disks (>70 deg.), and 3 highly inclined disks (>60 deg.) in our sample, we show that, as a population, embedded disks in Ophiuchus are not significantly contaminated by more evolved, but highly inclined sources. We derived dust disk masses from the Band 6 continuum and estimated gas disk masses from the C18O and C17O lines. The mass estimates from the C17O line are slightly higher, suggesting C18O emission might be partially optically thick. While the 12CO and 13CO lines are severely contaminated by extended emission and self-absorption, the C18O and C17O lines allowed us to trace the radial extent of the gaseous disks. From these measurements, we found that the C18O and C17O fluxes correlate well with each other and with the continuum fluxes. Furthermore, the C18O and C17O lines present a larger radial extension than disk dust sizes by factors ranging from 1.5 to 2.5, as it is found for Class II disks using the radial extension of the 12CO. In addition, we have detected outflows in three disks from 12CO observations.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): VI. Comparison of Dust Evolution Models to AGE-PRO Observations

The potential for planet formation of a circumstellar disk depends on the dust and gas reservoirs, which evolve as a function of the disk age. The ALMA Large Program AGE-PRO has measured several disk properties across three star-forming regions of different ages, and in this study we compare the observational results to dust evolution simulations. Using DustPy for the dust evolution, and RADMC-3D for the radiative transfer, we ran a large grid of models spanning stellar masses of 0.25, 0.50, 0.75, and 1.0 $M_\odot$, with different initial conditions, including: disk sizes, disk gas masses, and dust-to-gas ratio, and viscosity. Our models are performed assuming smooth, weakly, or strongly substructured disks, aiming to investigate if any observational trend can favor or exclude the presence of dust traps. The observed gas masses in the disks of the AGE-PRO sample are not reproducible with our models, which only consider viscous evolution with constant $α$, suggesting that additional physical mechanisms play a role in the evolution of the gas mass of disks. When comparing the dust continuum emission fluxes and sizes at 1.3 mm, we find that most of the disks in the AGE-PRO sample are consistent with simulations that have either weak or strong dust traps. The evolution of spectral index in the AGE-PRO sample is also suggestive of an unresolved population of dust traps. Future observations at high angular resolution are still needed to test several hypotheses that result from comparing the observations to our simulations, including that more massive disks in gas mass have the potential to form dust traps at larger disk radii.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): I. Program Overview and Summary of First Results

We present the ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO), a Large Program of the Atacama Large Millimeter/submillimeter Array (ALMA). AGE-PRO aims to systematically trace the evolution of gas disk mass and size throughout the lifetime of protoplanetary disks. It uses a carefully selected sample of 30 disks around M3-K6 stars in three nearby star-forming regions: Ophiuchus (0.5-1 Myr), Lupus (1-3 Myr), and Upper Sco (2-6 Myr). Assuming the three regions had similar initial conditions and evolutionary paths, we find the median gas disk mass appears to decrease with age. Ophiuchus disks have the highest median gas mass (6 M$_{\rm Jup}$), while the Lupus and Upper Sco disks have significantly lower median masses (0.68 and 0.44 M$_{\rm Jup}$, respectively). Notably, the gas and dust disk masses appear to evolve on different timescales. This is evidenced by the median gas-to-dust mass ratio, which decreases from 122 in the youngest disks ($<$1 Myr) to 46 in Lupus disks, and then increases to 120 in the Upper Sco disks. The median gas disk sizes range between 74-110 au, suggesting that typical gas disks are much smaller than those of well-studied, massive disks. Population synthesis models suggest that magneto-hydrodynamic wind-driven accretion can reproduce median disk properties across all three regions, when assuming compact disks with a declining magnetic field over time. In contrast, turbulent-driven models overestimate gas masses of $>$1 Myr disks by an order of magnitude. Here we discuss the program's motivation, survey design, sample selection, observation and data calibration processes, and highlight the initial results.

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arXiv2025

Cosmic cascades: How disk substructure regulates the flow of water to inner planetary systems

The influx of icy pebbles to the inner regions of protoplanetary disks constitutes a fundamental ingredient in most planet formation theories. The observational determination of the magnitude of this pebble flux and its dependence on disk substructure (disk gaps as pebble traps) would be a significant step forward. In this work we analyze a sample of 21 T Tauri disks (with ages $\approx 0.5{-}2\mathrm{~Myr}$) using JWST/MIRI spectra homogeneously reduced with the JDISCS pipeline and high-angular-resolution ALMA continuum data. We find that the 1500/6000 K water line flux ratio measured with JWST - a tracer of cold water vapor and pebble drift near the snowline - correlates with the radial location of the innermost dust gap in ALMA continuum observations (ranging from 8.7 to 69 au), confirming predictions from recent models that study connections between the inner and outer disk reservoirs. We develop a population synthesis exploration of pebble drift in gapped disks and find a good match to the observed trend for early and relatively effective gaps, while scenarios where pebble drift happens quickly, gaps are very leaky, or where gaps form late are disfavored on a population level. Inferred snowline pebble mass fluxes (ranging between $10^{-6}$ and $10^{-3}~M_\oplus/\mathrm{yr}$ depending on gap position) are comparable to fluxes used in pebble accretion studies and those proposed for the inner Solar System, while system-to-system variations suggest differences in the emerging planetary system architectures and water budgets.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): VIII. The impact of external photoevaporation on disk masses and radii in Upper Scorpius

Protoplanetary disk evolution can be deeply influenced by the UV radiation emitted by neighboring massive stars (mainly of spectral type O and B). We show that the process of external photoevaporation, which causes an outside-in depletion of disk material due to environmental UV radiation, can lead to a significant decrease in disk size, and moderate in disk mass and lifetime even at moderate irradiation levels (1-10 G$_{0}$). In this work we investigate the role of external photoevaporation in shaping the masses and sizes of the ten AGE-PRO disks in the Upper Scorpius region, which we estimate to be subject to FUV fluxes ranging between 2 and 12 G$_{0}$, on average. We compare the disk masses and sizes resulting from 1D numerical viscous evolution simulations in which the effect of external photoevaporation is included, to the values retrieved from the AGE-PRO observations. While the pure viscous framework fails in adequately explaining the observed disk properties in Upper Scorpius, with the inclusion of external photoevaporation we can successfully reproduce gas disk sizes for 7 out of 10 sources within a factor <2, when the initial disk mass is 1-10% of the stellar mass. We emphasize the importance of accounting for the environmental irradiation when comparing star-forming regions of different ages, even when moderate FUV irradiation fields are experienced, as in the case of Upper Scorpius.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): IV. Dust and Gas Disk Properties in the Upper Scorpius Star-forming Region

The Atacama Large Millimeter/submillimeter Array (ALMA) large program AGE-PRO explores protoplanetary disk evolution by studying gas and dust across various ages. This work focuses on ten evolved disks in Upper Scorpius, observed in dust continuum emission, CO and its isotopologues, and N$_2$H$^+$ with ALMA Bands 6 and 7. Disk radii, from the radial location enclosing 68% of the flux, are comparable to those in the younger Lupus region for both gas and dust tracers. However, solid masses are about an order of magnitude below those in Lupus and Ophiuchus, while the dust spectral index suggests some level of dust evolution. These empirical findings align with a combination of radial drift, dust trapping, and grain growth into larger bodies. A moderate correlation between CO and continuum fluxes suggests a link between gas and dust content, through the increased scatter compared to younger regions, possibly due to age variations, gas-to-dust ratio differences, or CO depletion. Additionally, the correlation between C$^{18}$O and N$_2$H$^+$ fluxes observed in Lupus persists in Upper Sco, indicating a relatively stable CO gas abundance over the Class II stage of disk evolution. In conclusion, the AGE-PRO survey of Upper Scorpius disks reveals intriguing trends in disk evolution. The findings point towards potential gas evolution and the presence of dust traps in these older disks. Future high-resolution observations are needed to confirm these possibilities and further refine our understanding of disk evolution and planet formation in older environments.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): XII. Extreme millimetre variability detected in a Class II disc

Variability of millimetre wavelength continuum emission from Class II protoplanetary disks is extremely rare, and when detected it is usually interpreted as originating from non-thermal emission mechanisms that relate to the host star itself rather than its disk. During observations made as part of the AGE-PRO ALMA Large program, significant variability in the brightness of the 2MASS J16202863-2442087 system was detected between individual executions. We report the observed properties of the variability detected at millimetre wavelengths and investigate potential driving mechanisms. To investigate the nature of the variability we construct a light curve from the continuum observations and analyse imaged constructed from both flaring and quiescent emission. We characterise the dust disk around the star through analysis in the image and visibility plane, and carry out kinematic analysis of the CO(2-1) emission from the gas disk. The continuum flux decays by a factor of 8 in less than an hour, and by a factor of 13 within 8 days. The peak brightness coincides with an expected brightness maximum extrapolated from the periodicity of previously observed optical variability. The flare is most likely the product of synchrotron emission in the close vicinity of the star. The nature of the millimetre flare closely resembles those detected in very close binary systems, and may be due to the interaction of magnetic fields in an as yet undetected binary. Alternatively if the central host is a single-star object, the flare may be due to the interaction of magnetic field loops at the stellar surface or a strong accretion burst.

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arXiv2025

The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO): III. Dust and Gas Disk Properties in the Lupus Star-forming Region

We present Band 6 and Band 7 observations of 10 Lupus disks around M3-K6 stars from the ALMA survey of Gas Evolution in PROtoplanetary disks (AGE-PRO) Large Program. In addition to continuum emission in both bands, our Band 6 setup covers the $\mathrm{{}^{12}CO}$, $\mathrm{{}^{13}CO}$ and $\mathrm{C^{18}O}\,J$=2-1 lines, while our Band 7 setup covers the $\mathrm{N_2H^+}\,J$=3-2 line. All of our sources are detected in $\mathrm{{}^{12}CO}$ and $\mathrm{{}^{13}CO}$, 7 out of 10 are detected in $\mathrm{C^{18}O}$, and 3 are detected in $\mathrm{N_2H^+}$. We find strong correlations between the CO isotopologue line fluxes and the continuum flux densities. With the exception of one disk, we also identify a strong correlation between the $\mathrm{C^{18}O}\,J$=2-1 and $\mathrm{N_2H^+}\,J$=3-2 fluxes, indicating similar CO abundances across this sample. For the two sources with well-resolved continuum and $\mathrm{{}^{12}CO}\,J$=2-1 images, we find that their gas-to-dust size ratio is consistent with the median value of $\sim 2$ inferred from a larger sample of Lupus disks. We derive dust disk masses from continuum flux densities. We estimate gas disk masses by comparing $\mathrm{C^{18}O}\,J$=2-1 line fluxes with those predicted by the limited grid of self-consistent disk models of Ruaud et al. (2022). A comparison of these mass estimates with those derived by Trapman et al. (2025), using a combination of CO isotopologue and $\mathrm{N_2H^+}$ line emission, shows that the masses are consistent with each other. Some discrepancies appear for small and faint disks, but they are still within the uncertainties. Both methods find gas disk masses increase with dust disk masses, and gas-to-dust mass ratios are between $10-100$ in the AGE-PRO Lupus sample.

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arXiv2025

A young gas giant and hidden substructures in a protoplanetary disk

The detection of planets in protoplanetary disks has proven to be extremely challenging. In contrast, rings and gaps, usually attributed to planet-disk interactions, have been found in virtually every large protoplanetary (Class II) disk observed at 0.9-1.3 mm with sufficient spatial resolution (5 au). The nearby disk around MP Mus (PDS 66) stands as an exception to this rule, and its advanced age (7-10 Myr) is particularly difficult to reconcile with its apparent lack of substructures. Despite the disk's smooth appearance, Gaia data of MP Mus show a significant proper motion anomaly, signalling the presence of a companion. Here we present ALMA 3 mm observations of the system with comparable high spatial resolution to previous 1.3 mm data. The new observations pierce deeper into the disk midplane and reveal an inner cavity (<3 au) and a ring at 10 au. The disk structure inferred from ALMA observations narrows down the properties of the companion to a gas giant orbiting at 1-3 au, and hydrodynamic simulations further confirm that such a planet can produce the observed cavity. These independent pieces of evidence constitute an indirect but compelling detection of an exoplanet within a protoplanetary disk using Gaia astrometry. MP Mus is the first system in which undetected substructures are revealed thanks to the lower optical depths at longer wavelengths, suggesting that rings and gaps are even more abundant than what is currently believed.

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arXiv2025

The JDISC Survey: Linking the Physics and Chemistry of Inner and Outer Protoplanetary Disk Zones

Mid-infrared spectroscopy of protoplanetary disks provides a chemical inventory of gas within a few au, where planets are readily detected around older stars. With the JWST Disk Infrared Spectral Chemistry Survey (JDISCS), we explore demographic trends among 31 disks observed with MIRI (MRS) and with previous ALMA millimeter continuum imaging at high angular resolution (5-10 au). With these S/N $\sim$200-450 spectra, we report emission from H$_2$O, OH, CO, C$_2$H$_2$, HCN, CO$_2$, [Ne II], [Ne III], and [Ar II]. Emission from H$_2$O, OH and CO is nearly ubiquitous for low-mass stars, and detection rates of all molecules are higher than for similar disks observed with Spitzer-IRS. Slab model fits to the molecular emission lines demonstrate that emission from C$_2$H$_2$, HCN, and possibly CO$_2$ is optically thin; thus since column densities and emitting radii are degenerate, observations are actually sensitive to the total molecular mass. C$_2$H$_2$ and HCN emission also typically originate in a hotter region ($920^{+70}_{-130}$, $820^{+70}_{-130}$ K, respectively) than CO$_2$ ($600^{+200}_{-160}$ K). The HCN to cold H$_2$O luminosity ratios are generally smaller in smooth disks, consistent with more efficient water delivery via icy pebbles in the absence of large dust substructures. The molecular emission line luminosities are also correlated with mass accretion rates and infrared spectral indices, similar to trends reported from Spitzer-IRS surveys. This work demonstrates the power of combining multi-wavelength observations to explore inner disk chemistry as a function of outer disk and stellar properties, which will continue to grow as the sample of observed Class II systems expands in the coming JWST observation cycles.

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arXiv2025

Hints of planet formation signatures in a large-cavity disk studied in the AGE-PRO ALMA Large Program

Detecting planet signatures in protoplanetary disks is fundamental to understanding how and where planets form. In this work, we report dust and gas observational hints of planet formation in the disk around 2MASS-J16120668-301027, as part of the ALMA Large Program "AGE-PRO: ALMA survey of Gas Evolution in Protoplanetary disks". The disk was imaged with the Atacama Large Millimeter/submillimeter Array (ALMA) at Band 6 (1.3 mm) in dust continuum emission and four molecular lines: $^{12}$CO(J=2-1), $^{13}$CO(J=2-1), C$^{18}$O(J=2-1), and H$_2$CO(J=3$_{(3,0)}$-2$_{(2,0)}$). Resolved observations of the dust continuum emission (angular resolution of $\sim 150$ mas, 20 au) show a ring-like structure with a peak at $0.57 ^{\prime \prime}$ (75 au), a deep gap with a minimum at 0.24$^{\prime \prime}$ (31 au), an inner disk, a bridge connecting the inner disk and the outer ring, along with a spiral arm structure, and a tentative detection (to $3σ$) of a compact emission at the center of the disk gap, with an estimated dust mass of $\sim 2.7-12.9$ Lunar masses. We also detected a kinematic kink (not coincident with any dust substructure) through several $^{12}$CO channel maps (angular resolution $\sim$ 200 mas, 30 au), located at a radius of $\sim 0.875^{\prime \prime}$ (115.6 au). After modeling the $^{12}$CO velocity rotation around the protostar, we identified a tentative rotating-like structure at the kink location with a geometry similar to that of the disk. We discuss potential explanations for the dust and gas substructures observed in the disk, and their potential connection to signatures of planet formation.

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