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 Atacama Large Millimeter/submillimeter Array 12 m and Atacama Compact Array, we present new Band 7 dust continuum and molecular line observations of GY 91 at an angular resolution of similar to 0.'' 3 (40 au). We report detections of CS J = 6-5, N2H+ J = 3-2, C18O J = 3-2, H2CS JKa,Kc=81,7-71,6 , H2CO JKa,Kc=40,4-30,3 , and H2CO JKa,Kc=42,3-32,2 , as well as a tentative detection of 13C18O J = 3-2. We observe azimuthal asymmetry in CS and H2CS emission, as well as radially structured H2CO 40,4-30,3 emission outside the dust continuum. C18O and H2CO 40,4-30,3 show significant cloud contamination, while CS and N2H+ 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 circle dot, which is higher than previous estimates from stellar evolutionary models (0.25 M circle dot). Using both radiative transfer modeling of the dust continuum and comparison of the C18O and N2H+ fluxes to literature thermochemical models, we estimate a disk mass of similar to 0.01 M circle dot.

A large fraction of planet-forming disks observed with ALMA show faint CO emission, often interpreted as strong CO depletion. However, faint emission may also arise from spatially unresolved disks, whose sizes are overestimated, making them appear intrinsically faint. The limited sensitivity of previous observations has prevented testing this scenario, hindering our understanding of disk evolution and planet formation. We present new ALMA Band 7 observations of 12CO (J=3-2) and 13CO (J=3-2) in 17 of the faintest disks in Lupus, aiming to assess whether compact disk structure can explain their weak CO emission. The data reach an angular resolution of 0.25arcsec (about 20 au at 160 pc) and are an order of magnitude deeper than archival observations. We apply line stacking to enhance sensitivity and compare the derived CO luminosities with physical-chemical models of compact and extended disks, also estimating gas and dust sizes. We detect both isotopologues in 10 disks, only 12CO in 4, and neither in 3. Several disks are consistent with being intrinsically compact and optically thick in both lines, providing an alternative to the CO depletion scenario. The inferred gas radii (Rco less than 40 au) support this interpretation and suggest that a significant fraction of disks may be born compact, in line with recent Class 0/I results. Gas-to-dust size ratios show no clear evidence for dust evolution, indicating these disks are not drift-dominated.

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 Atacama Large Millimeter/submillimeter Array 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 10 times of the Interstellar Medium (ISM) abundance levels. For HD 163296 and MWC 480, the inferred enhancements require 250–350 and 480–660 M _⊕ 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.

We present deep, high-resolution (similar to 100 mas) Karl G. Jansky Very Large Array Ka-band (9.1 mm) observations of the disk around MWC 480 and infer dust properties through a combined analysis with archival Atacama Large Millimeter/submillimeter Array data at 0.87, 1.17, 1.33, and 3.0 mm. The prominent dust ring at 95 au (B95) is detected at 9.1 mm for the first time, while the faint outer ring at 160 au is not revealed. Through nonparametric visibility modeling, we identified two new annular features: a plateau within 20-50 au across all wavelengths, and a shoulder exterior to the B95 ring at 0.87, 1.17, and 1.33 mm, consistent with signatures of planet-disk interaction. We find that the width of the B95 ring remains constant across wavelengths, suggesting that fragmentation dominates over radial diffusion or that unresolved substructure is present within the ring. Resolved spectral modeling yields two families of dust solutions that reproduce the observations equally well: compact grains or highly porous (90%) grains, with carbonaceous components dominated by refractory organics or amorphous carbon, respectively. The inferred maximum grain sizes peak at the locations of the two rings and reach centimeter within the B95 ring. The total dust masses are 860-78+95M circle plus / 1500-330+440M circle plus (large/small-grain solution in inner disk) and 230-13+14M circle plus for the two dust mixtures. The B95 ring alone contains 100-5+5M circle plus and 43-2+2M circle plus , respectively, sufficient to assemble the cores of giant planets. Finally, we highlight the power of broadband, multiwavelength observations in placing better constraints on dust composition and porosity in protoplanetary disks.

The A1V star gamma Oph, at a distance of 29.7 pc, is known from Spitzer imaging to host a debris disk with a large radial extent and from its spectral energy distribution to host inner warm dust. We imaged gamma Oph with the James Webb Space Telescope (JWST)/Mid-InfraRed Instrument at 15 and 25.5 mu m, revealing smooth and radially broad emission that extends to a radius of at least 250 au at 25.5 mu m. In contrast to JWST findings of an inner small-grain component with distinct ringed structures in Fomalhaut and Vega, the mid-infrared radial profile combined with prior Atacama Large Millimeter/submillimeter Array imaging suggests a radially broad steady-state collisional cascade with the same grain size distribution throughout the disk. This further suggests that the system is populated by a radially broad planetesimal belt from tens of astronomical units or less to well over 200 au, rather than a narrow planetesimal belt from which the observed dust is displaced to appear broad. The disk is also found to be asymmetric, which could be modeled by a stellocentric offset corresponding to a small eccentricity of similar to 0.03. Such a disk eccentricity could be induced by a mildly eccentric <10 M-Jup giant planet outside 10 au, or a more eccentric companion up to stellar mass at a few astronomical units, without producing a resolvable radial gap in the disk.

We present a survey of 24 Herbig Be stars (young stellar objects >3 M_⊙) within 3 kpc at 1.3 millimeters using the Submillimeter Array at about 1” resolution to identify circumstellar disks and assess planet forming potential. We detect 1.3 mm emission toward 5 Herbig Be stars that range in mass from 4.3 to 12.9 M_⊙. Follow-up observations at 0.87 mm show spectral indices consistent with partly optically thick dust emission. These millimeter detections are compatible with an extrapolation of the scaling relation derived for lower-mass T Tauri and Herbig Ae stars between millimeter luminosity and stellar host mass, and also millimeter continuum size, suggesting these detections represent emission from circumstellar disks. The implied disk masses are sufficient for giant planet formation. No decrease in the millimeter detection fraction with stellar host mass is evident within this sample that would implicate rapid disk dissipation by the radiation fields of the higher mass stars. The high fraction of millimeter non-detections is likely due to the survey sensitivity limits together with photoevaporation and the dynamical impact of stellar companions.

Context. Over 20 exocometary belts host detectable circumstellar gas, mostly in the form of CO. Two competing theories for its origin have emerged, positing that the gas is either primordial or secondary. Primordial gas survives from the belt's parent protoplanetary disc and is therefore H-2-rich. Secondary gas is outgassed in situ by exocomets and is relatively H-2-poor. Discriminating between these scenarios has not been possible for belts that host unexpectedly large quantities of CO. Aims. We aim to break this gas origin dichotomy through direct measurement of H-2 column densities in two edge-on, CO-rich exocometary belts around similar to 15 Myr-old A-type stars, constraining the CO/H-2 ratio and CO gas lifetimes. Observing edge-on belts enables rovibrational absorption spectroscopy against the stellar background. Methods. We present near-IR CRIRES+ spectra of HD 110058 and HD 131488, which provide the first direct probe of H-2 gas in CO-rich exocometary belts. We targeted the H-2 (v=1-0 S(0)) line at 2223.3 nm and the (CO)-C-12 v = 2 -> 0 rovibrational lines in the range 2333.8-2335.5 nm and derived constraints on column densities along the line of sight to the stars. Results. We detect (CO)-C-12 strongly, but not H-2, in the CRIRES+ spectra. This allows us to place 3 sigma lower limits on the CO/H-2 ratios of >1.35 & times; 10(-3) and >3.09 & times; 10(-5) for HD 110058 and HD 131488, respectively. These constraints demonstrate that, at least for HD 110058, the exocometary gas is compositionally distinct and significantly H-2-poor compared to the <10(-4) CO/H-2 ratios typical of protoplanetary discs. For HD 131488, we further compared the CO photodissociation timescale to the age of the system through simple shielding arguments, and find that we cannot formally rule out a primordial origin; however, we suggest that a more realistic model of CO survival likely supports a secondary origin for this system as well. Overall, a high CO/H-2 ratio for HD 110058 indicates that the gas in this CO-rich belt is most likely not primordial in composition, supporting the presence of exocometary gas.

Disks (Keplerian or otherwise, particulate or fluid) are often assumed to have densities that drop off vertically as Gaussians. Recent mm-wave imaging of circumstellar debris disks contradicts this assumption, revealing vertical profiles in dust that resemble Lorentzians. As part of the ARKS ALMA Large Program, we calculate how Lorentzians and Gaussians define an evolutionary sequence for disks of gravitationally scattering (viscously stirring) particles. When orbits are crossing and eccentricities e ≫ inclinations i, each scattering changes a particle's inclination by ± Δi ∝ i. A random walk with fixed steps in Δi/i = Δln i produces a log normal i distribution, whose thick tail at large i leads to thick Lorentzian tails in density. This result holds independent of the origin of the large eccentricities; what matters is that relative motions parallel to the disk midplane are faster than perpendicular motions. After enough scatterings, i comes into equipartition with e, Δi stops exponentiating, and the vertical density profile relaxes to a Gaussian. We estimate the numbers and masses of perturbers needed to stir themselves and observable dust grains in Lorentzian and Gaussian debris disks imaged by ARKS. The big bodies may be sufficiently few in number as to be collisionless, in which case their masses range from the Moon to several Earths. But if Pluto-sized or smaller, the big body stirrers may be so numerous and collide so frequently that they can source the collisional cascades that produce observable dust.

We present high-resolution ( less than or similar to 0.'' 1 ) Hubble Space Telescope/Wide Field Camera 3 imaging of the near edge-on (i similar to 80 degrees) protoplanetary disk IRAS23077+6707 ("Dracula's Chivito"), obtained across six broadband filters spanning 0.4-1.6 mu m. These observations unveil the scattered light from this unusually large disk (similar to 14 '', or similar to 4200 au at 300 pc) in remarkable detail, revealing a rich tapestry of substructures, including brightness asymmetries and signatures of dynamical activity. Extended filaments are detected extending similar to 10 '' from the northern edges of both nebulae, while no comparable southern features are observed. In addition to large-scale asymmetries, the disk exhibits prominent wispy features that extend well above the midplane and are visible in all filters, suggesting a complex, possibly turbulent outer disk atmosphere shaped by infall, dynamical stirring, or gravitational instability. The central dark lane narrows from optical to near-IR wavelengths, and high-resolution millimeter data reveal compact midplane emission. Although our radiative transfer simulations show that the current data cannot yet distinguish between dust settling and no-settling scenarios, they underscore the need for resolved midinfrared observations of this unique system. IRAS23077 thus represents a rare and valuable laboratory for studying the vertical structure, asymmetries, and evolutionary state of protoplanetary disks.

We present a survey of 24 Herbig Be stars (young stellar objects >3 M-circle dot) within 3 kpc at 1.3 mm using the Submillimeter Array at similar to 1 '' resolution to identify circumstellar disks and assess planet forming potential. We detect 1.3 mm emission toward five Herbig Be stars that range in mass from 4.3 to 12.9 M-circle dot. Follow-up observations at 0.87 mm show spectral indices consistent with partly optically thick dust emission. These millimeter detections are compatible with an extrapolation of the scaling relation derived for lower-mass T Tauri and Herbig Ae stars between millimeter luminosity and stellar host mass and also millimeter continuum size, suggesting these detections represent emission from circumstellar disks. The implied disk masses are sufficient for giant planet formation. No decrease in the millimeter detection fraction with stellar host mass is evident within this sample that would implicate rapid disk dissipation by the radiation fields of the higher-mass stars. The high fraction of millimeter nondetections is likely due to the survey sensitivity limits together with photoevaporation and the dynamical impact of stellar companions.

The physical and chemical conditions of protoplanetary disks shape the properties of nascent planetary systems. The line ratios and relative abundances of the HCN-HNC isomer pair are well-suited for tracing these gas conditions, since isomer chemistry is linked to the underlying temperature, elemental abundances, and irradiation environment of the emitting gas. While HCN emits bright lines regularly observed in disks, the fainter HNC lines are targeted significantly less often, precluding our ability to calibrate the HNC-to-HCN ratio as a tracer of disk properties. Here, we present new Submillimeter Array observations of five transition disks around the T Tauri stars GM Aur, J1604, LkCa 15, GG Tau, and V4046 Sgr, covering the J=3-2 and J=4-3 lines of HCN and HNC. We detected at least one line of both HCN and HNC in each source and measured disk-integrated HNC-to-HCN flux and column density ratios of ≈0.1-0.7 and 0.1-0.4, respectively. For all sources, measured HNC fluxes exceed predictions from models of full (non-transition) disks by ≈3-10x, while HCN fluxes appear typical. The relative brightness of HNC vs. HCN in transition disks strongly suggests a link between the presence of a cavity and efficient HNC production. We corroborate this trend using chemical models of the DM Tau transition disk, showing HNC production and destruction are connected to the radiation environment. In our sample, disk-integrated HNC-to-HCN column density ratio shows no trend with disk gas temperature but positively correlates with disk mass due to increased HNC abundance in the larger reservoirs of cooler gas in more massive disks.

Bow-shock pulsar wind nebulae (PWNe) are synchrotron sources formed when the outflow of supersonic pulsars is confined by the surrounding interstellar medium. These sources are dominated by freshly injected particles, thus providing a unique laboratory for studying particle acceleration in relativistic outflows. The Mouse is a prototypical bow-shock PWN and is bright in the radio and X-ray bands, enabling detailed multi-wavelength spectral modeling. Using data from 17 telescopes, the Mouse is detected from 118 MHz to 353 GHz, covering over 3 decades in frequency, and in X-rays from 0.5 to 30 keV. A clear spectral break is identified at 3.7 GHz. The radio spectrum exhibits a rising trend at low frequency, peaks at the break, and then declines. We find a change in spectral index Δα=0.65±0.05 across the break. We attribute this to an intrinsic cutoff or steepening in the injected particle distribution. This could indicate the characteristic energy of leptons leaving the pulsar magnetosphere, or energy dissipation after the particles cross the termination shock.

We present an infrared, millimetre, and radio survey of 20 Class 0-III young stellar objects in the Ophiuchus A L1688 star-forming cluster, combining high-resolution (7-25 au) VLA and JWST observations with archival ALMA data. We implement physically motivated models to derive dust and ionised gas properties, spectral behaviour and their relative contributions through the millimetre-centimetre radio spectral energy distribution. Our models reveal circumstellar dust disks that are, on average, tens to hundreds of times more massive than millimetre-only estimates (subject to uncertainties arising from the choice of dust opacity) and contain millimetre-sized grains even at the Class 0 stage. Owing to the VLA's high resolution we are able to connect outflows to their origins, detecting protostellar jet emission on scales of 10s-1000s au. Our results represent a homogeneous characterisation of the dust and ionised gas properties in Ophiuchus and present a potential solution to the long-standing 'missing disk mass' problem. However, our understanding is still limited by resolution and sensitivity at frequencies <40 GHz. Future facilities like the SKA and ngVLA are needed to provide the necessary capabilities to fully spatially resolve this emission (<0.18") even in one of the closest star-forming regions.

CO isotopologue emission is widely used to infer gas masses and volatile carbon abundances in protoplanetary disks, but converting line emission into a CO column depends on optical depth, temperature structure, linewidth, and isotope ratios. Inferring CO/H_2 additionally requires an independent constraint on the local hydrogen column. We use high-resolution ^13C^18O 2-1 observations of HD 163296 to derive a spatially localized empirical constraint on the CO column at the resolved CO snowline edge. We focus on the 70-75 au annulus, on the inner, high-column side of the observed profile steepening near 75 au. Using RADEX slab calculations conditioned on a two-dimensional temperature structure, we infer an effective beam-averaged CO column from the absolute integrated intensity. Across representative temperatures, isotope-ratio pairs, and effective local linewidths of 0.30 and 0.50 km s^-1, we find N_ CO^ beam=(1.6-2.4)×10^20 cm^-2 and ^13C^18O line-center optical depths τ=0.39-0.97. Thus, even this rare isotopologue is not safely optically thin at the snowline edge. Adopting N_ H2=2.5×10^24 cm^-2 from a published parametric gas surface-density profile gives the conditional abundance CO/H_2=(6.4-9.5)×10^-5. A beam-forward radial-profile analysis gives consistent columns, and a physical disk model with a near-canonical warm-layer CO abundance supplies a comparable CO column. The measurement is consistent with the higher C^17O-based MAPS estimate. For the adopted hydrogen column, the inferred CO/H_2 ratio is consistent with a near-canonical abundance on the warm side of the snowline.

We present new observations that densely sample the microwave (4-360 GHz) continuum spectra from eight young systems in the Taurus region. Multi-component, empirical model prescriptions were used to disentangle the contributions from their dust disks and other emission mechanisms. We found partially optically thick, free-free emission in all these systems, with positive spectral indices (median α_ c≈ 1 at 10 GHz) and contributing 5-50

The bulk motion of the gas in protoplanetary disks around newborn stars is nearly Keplerian. By leveraging the high angular and spectral resolution of the Atacama Large Millimeter/submillimeter Array (ALMA), we can detect small-scale velocity perturbations in molecular line observations caused by local gas pressure variations in the disk, possibly induced by embedded protoplanets. This Letter presents the azimuthally averaged rotational velocity and its deviations from Keplerian rotation ( δυ _ϕ ) for the exoALMA sample, as measured in the ^12 CO J = 3–2 and ^13 CO J = 3–2 emission lines. The rotation signatures show evidence for vertically stratified disks, in which ^13 CO rotates faster than ^12 CO due to a distinct thermal gas pressure gradient at their emitting heights. We find δυ _ϕ substructures in the sample on both small (∼10 au) and large (∼100 au) radial scales, reaching deviations up to 15% from background Keplerian velocity in the most extreme cases. More than 75% of the rings and 80% of the gaps in the dust continuum emission resolved in δυ _ϕ are colocated with gas pressure maxima and minima, respectively. Additionally, gas pressure substructures are observed far beyond the dust continuum emission. For the first time, we determined the gas pressure derivative at the midplane from observations, and found it to align well with the dust substructures within the given uncertainties. Based on our findings, we conclude that gas pressure variations are likely the dominant mechanism for ring and gap formation in the dust continuum.

Over the past decade, several millimeter interferometer programs have mapped the nearby star-forming galaxy M51 at a spatial resolution of <= 170 pc. This study combines observations from three major programs: the PdBI Arcsecond Whirlpool Survey, the SMA M51 large program, and the Surveying the Whirlpool at Arcseconds with NOEMA. The data set includes the (1-0) and (2-1) rotational transitions of (CO)-C-12, (CO)-C-13, and (CO)-O-18 isotopologues. The observations cover the r < 3 kpc region, including the center and part of the disk, thereby ensuring strong detections of the weaker (CO)-C-13 and (CO)-O-18 lines. All observations are convolved in this analysis to an angular resolution of 4 '', corresponding to a physical scale of 170 pc. We investigate empirical line ratio relations and quantitatively evaluate molecular gas conditions such as temperature, density, and the CO-to-H-2 conversion factor (alpha(CO)). We employ two approaches to study the molecular gas conditions: (i) assuming local thermodynamic equilibrium (LTE) to analytically determine the CO column density and alpha(CO), and (ii) using non-LTE modeling with RADEX to fit physical conditions to observed CO isotopologue intensities. We find that the alpha(CO) values in the center and along the inner spiral arm are similar to 0.5 dex (LTE) and 0.1 dex (non-LTE) below the Milky Way inner disk value. The average non-LTE alpha(CO) is 2.4 +/- 0.5 M-circle dot pc(-2) (K km s(-1))(-1). While both methods show dispersion due to underlying assumptions, the scatter is larger for LTE-derived values. This study underscores the necessity for robust CO line modeling to accurately constrain the molecular interstellar medium's physical and chemical conditions in nearby galaxies.

We analyze the ^12 CO J = 3–2 data cubes of the disks in the exoALMA program. 13/15 disks reveal a variety of kinematic substructures in individual channels: large-scale arcs or spiral arms, localized velocity kinks, and/or multiple faints arcs that appear like filamentary structures on the disk surface. We find kinematic signatures that are consistent with planet wakes in six disks: AA Tau, SY Cha, J1842, J1615, LkCa 15, and HD 143006. Comparison with hydrodynamical and radiative transfer simulations suggests planets with orbital radii between 80 and 310 au and masses between 1 and 5 M _Jup . Additional kinematic substructures limit our ability to place tight constraints on the planet masses. When the inclination is favorable to separate the upper and lower surfaces (near 45°, i.e., in 7/15 disks), we always detect the vertical CO snowline and find that the ^12 CO freeze-out is partial in the disk midplane, with a depletion factor of ≈10 ^−3 –10 ^−2 compared to the warm molecular layer. In these same seven disks, we also systematically detect evidence of CO desorption in the outer regions.

We present high-resolution data of IRAS 23077+6707 (`Dracula's Chivito') with the Submillimeter Array (SMA at 1.33 mm/225.5 GHz) and the Northern Extended Millimeter Array (NOEMA at 2.7 mm/111.7 GHz and 3.1 mm/96.2 GHz). IRAS 23077+6707 is a highly-inclined and newly discovered protoplanetary disk, first reported in 2024. We combine SMA baselines from the Compact, Extended and Very Extended arrays, and NOEMA baselines from its A and C configurations, and present continuum images with resolution ≲0.8”, which constitute the first sub-arcsecond resolution maps of IRAS 23077+6707. The images show extended linear emission that spans 5.6-6.1” as expected for a radially extended, highly-inclined protoplanetary disk. Accompanied with lower resolution data, we show that the disk has a steep spectral index, ranging from α=3.2-3.9. We present evidence of multiple radial emission peaks and troughs in emission, which may originate in disk rings and a central cavity. We further present evidence that these radial structures are asymmetric; hosting a a significant brightness asymmetry, with emission enhanced by up to 50

We present a JWST MIRI/MRS spectrum of the inner disk of WISE J044634.16–262756.1B (hereafter J0446B), an old (∼34 Myr) M4.5 star but with hints of ongoing accretion. The spectrum is molecule-rich and dominated by hydrocarbons. We detect 14 molecular species (H 2 , CH 3 , CH 4 , C 2 H 2 , 13 CCH 2 , C 2 H 4 , C 2 H 6 , C 3 H 4 , C 4 H 2 , C 6 H 6 , HCN, HC 3 N, CO 2 , and 13 CO 2 ) and two atomic lines ([Ne ii ] and [Ar ii ]), all observed for the first time in a disk at this age. The detection of spatially unresolved H 2 and Ne gas strongly supports that J0446B hosts a long-lived primordial disk, rather than a debris disk. The marginal H 2 O detection and the high C 2 H 2 /CO 2 column density ratio indicate that the inner disk of J0446B has a very carbon-rich chemistry, with a gas-phase C/O ratio ≳2, consistent with what has been found in most primordial disks around similarly low-mass stars. In the absence of significant outer disk dust substructures, inner disks are expected to first become water-rich due to the rapid inward drift of icy pebbles and evolve into carbon-rich as outer disk gas flows inward on longer timescales. The faint millimeter emission in such low-mass star disks implies that they may have depleted their outer icy pebble reservoir early and already passed the water-rich phase. Models with pebble drift and volatile transport suggest that maintaining a carbon-rich chemistry for tens of Myr likely requires a slowly evolving disk with α -viscosity ≲10 −4 . This study represents the first detailed characterization of disk gas at ∼30 Myr, strongly motivating further studies into the final stages of disk evolution.