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arxiv: 2604.11247 · v1 · submitted 2026-04-13 · 🌌 astro-ph.SR · astro-ph.EP· astro-ph.GA

Observations of highly inclined disks with ALMA. Results from 12CO gas and continuum observations

Laurine Martinien , Gaspard Duch\^ene , \'Alvaro Ribas , Marion Villenave , Fran\c{c}ois M\'enard , Karl R. Stapelfeldt , Christophe Pinte This is my paper

Pith reviewed 2026-05-10 15:56 UTC · model grok-4.3

classification 🌌 astro-ph.SR astro-ph.EPastro-ph.GA
keywords protoplanetary disksALMA observationsradial extentvertical settlingdust evolutiondynamical massinclined disksCO gas emission
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The pith

Most highly inclined protoplanetary disks show gas extending farther out than dust at both micron and millimeter scales.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper studies 14 highly inclined protoplanetary disks with ALMA continuum and carbon monoxide line data plus scattered-light images to measure how far the gas and different sizes of dust reach in radius and height. Eleven of the disks follow a clear size ordering in which the gas disk is largest, followed by micron-sized dust, then millimeter-sized dust. Most disks also show the gas layer thicker than the settled millimeter dust layer near the midplane. The work confirms that more massive disks are flatter and that inclination-corrected fluxes strengthen the known size-flux relation, pointing to optically thick millimeter emission.

Core claim

The majority of the sample follows Rgas > Rdust,micron > Rdust,mm radially and Hgas > Hdust,mm vertically, with an anti-correlation between dynamical mass and disk aspect ratio. These patterns are measured from ALMA band-7 images and 12CO moment maps combined with scattered-light data, and dynamical masses are derived from position-velocity diagrams for most objects. The results indicate that millimeter dust is vertically settled and radially drifted inward relative to the gas, while micron dust is only partially coupled to the gas.

What carries the argument

Direct comparison of radial extents (gas, micron dust, millimeter dust) and vertical extents (gas versus millimeter dust) extracted from images and moment maps, together with dynamical masses from position-velocity diagrams.

If this is right

  • Millimeter dust forms a thin midplane layer because it is vertically decoupled from the gas.
  • Inclination corrections make the disk size-flux correlation tighter, consistent with optically thick millimeter emission.
  • Gravity dominates the vertical structure, as shown by the anti-correlation between dynamical mass and aspect ratio.
  • Highly inclined disks appear less extended in CO than in millimeter dust because of optical depth and radial drift effects.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The observed size hierarchy may set preferred locations for dust concentration and planetesimal formation at specific radii.
  • Repeating the analysis on a larger sample of face-on disks would test whether the same ordering holds when vertical heights can be measured directly.
  • The mass-aspect ratio trend implies that disks around higher-mass stars may experience different migration timescales for forming planets.

Load-bearing premise

The apparent sizes measured in the images and moment maps accurately reflect the true physical extents after corrections for optical depth, projection effects in inclined systems, and Keplerian assumptions in the velocity diagrams.

What would settle it

Discovery of a highly inclined disk in which the millimeter continuum extends beyond the CO gas emission after inclination and optical-depth corrections would contradict the reported radial size ordering.

Figures

Figures reproduced from arXiv: 2604.11247 by \'Alvaro Ribas, Christophe Pinte, Fran\c{c}ois M\'enard, Gaspard Duch\^ene, Karl R. Stapelfeldt, Laurine Martinien, Marion Villenave.

Figure 1
Figure 1. Figure 1: Continuum images of the newly observed sources normalized to their peak intensity (reported in the bottom right corner of each image). The beam size (ellipse) and a 0′′ .5 scale (dark line) are shown in the bottom left corner of each panel. Mackey (2018), applying a 3σ clipping. The companions in bi￾nary systems (third row on [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: 12CO moment 1 maps of the 14 disks in both surveys. The first two rows correspond to edge-on disks, the third row to multiple systems with one edge-on disk and the last row to grazing-angle disks. firmed in the millimeter continuum image of Lup 160708 (see [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Position-velocity diagrams with 3 Keplerian velocity curves corresponding to the preferred dynamical mass of the star, as well as conser￾vative upper and lower limits. 4. Results from HST and VLT optical and near-infrared scattered light In this section, we estimate the radial and vertical extents of the scattered light. Villenave et al. (2020) reported the radial extent of all but one of their disks and w… view at source ↗
Figure 4
Figure 4. Figure 4: Overlay of scattered light (grayscale image), ALMA 0.9 mm continuum (blue contours) and ALMA 12CO gas (semi-transparent red image) for all sources in this study. The scattered light images are plotted on a logarithmic stretch and the contours of ALMA continuum are plotted at 30, 50, 70, and 90% of the maximum emission, except for the binaries for which we adjusted the contours due to the brightness of the … view at source ↗
Figure 5
Figure 5. Figure 5: Comparison between disks radius in gas, millimeter dust and scattered light dust in the radial direction (top row) and disks heights (bottom row). We added radius measurements of Class II disks in the millimeter dust from Ansdell et al. (2018); Vioque et al. (2025), in the scattered light dust from Avenhaus et al. (2018); Garufi et al. (2020) and in the gas from Pinte et al. (2018); Galloway-Sprietsma et a… view at source ↗
Figure 6
Figure 6. Figure 6: Disk radii measured in the ALMA continuum (top row) and 12CO 3–2 line (bottom row) as a function of their submillimeter continuum and line flux (scaled to 140 pc for uniformity), respectively. Small circles represent low- to moderate-inclination disks from the literature (Hendler et al. 2020; Zallio et al. 2026) while large circles and squares are highly inclined disks from this study in single and multipl… view at source ↗
Figure 7
Figure 7. Figure 7: Millimeter dust disk radius as a function of stellar mass. dependence with the separation between components in the sys￾tem. However, Rota et al. (2022) found that the ratio of the dust to gas ratio in multiple stellar systems is lower compared to sin￾gle stars, which is in agreement with what we found (see Fig. 5a). PDS 144 N Lup 160703 Haro 6-5B HV Tau C HH 48 NE HK Tau B Tau 042021 Tau 042307 Oph 163131… view at source ↗
Figure 9
Figure 9. Figure 9: Dynamical mass as a function of aspect ratio (h/r), which repre￾sents the vertical extent over the radial extent of 12CO gas. Flying Saucer is shown in gray to represent the low SNR (see Sect. 3) and is not in￾cluded in the statistical test presented in Sect. 3.5 . stars for all disk-hosting companions: HK Tau A, PDS 144 S and HH 48 SW. All values are summarized in Appendix B. The pri￾mary star in a multip… view at source ↗
read the original abstract

[Abridged] We aim to study the radial and vertical extents of 12CO gas, millimeter dust thermal emission and optical/NIR scattered light by dust in disks. We analyze a sample of 14 highly inclined protoplanetary disks. We present ALMA high angular resolution band 7 (0.9 mm) continuum images and 12CO (3-2) gas moment maps as well as HST and VLT/SPHERE scattered light images. The majority of disks in our sample (11 out of 14) follow Rgas > Rdust,micron > Rdust,mm. The other 3 disks appear more extended in millimeter continuum than in scattered light. Highly inclined disks tend to appear less radially extended in CO gas line emission than in millimeter dust continuum compared to less inclined disks. This results from optical depth effects and/or radial drift. The known correlation between disk size and millimeter continuum and line fluxes are confirmed in our sample with highly inclined disks significantly fainter than disks seen at lower inclination for a given disk radius. We found that this correlation is significantly tightened once fluxes are corrected for the disk inclination, consistent with the disks being optically thick at millimeter wavelengths. Regarding the vertical extent defined as the apparent emitting height, most disks in our sample follow Hgas > Hdust, mm. This strengthens our previous findings that the millimeter dust is highly decoupled from the gas and forms a layer in the disk midplane due to vertical settling. Most disks appear more vertically extended in gas than in scattered light, suggesting that the micron-sized dust is not fully coupled to the gas. We also estimated dynamical masses using PV diagrams for the first time for most of the objects in our sample. We found an anti-correlation between the dynamical mass and the aspect ratio, emphasizing the dominant role of gravity in setting the disk vertical extent, but no correlation with the disk radius.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 3 minor

Summary. The paper presents ALMA Band 7 (0.9 mm) continuum and 12CO(3-2) observations of 14 highly inclined protoplanetary disks, supplemented by HST and VLT/SPHERE scattered-light images. It reports that 11/14 disks follow the radial size ordering R_gas > R_dust,micron > R_dust,mm, that most disks show H_gas > H_dust,mm, and that dynamical masses derived from PV diagrams exhibit an anti-correlation with disk aspect ratio. The work also notes that highly inclined disks appear less CO-extended than mm-continuum extended relative to face-on samples (attributed to optical depth and/or radial drift), confirms the disk size-flux correlation, and finds that inclination-corrected fluxes tighten this relation.

Significance. If the reported size orderings and mass-aspect ratio anti-correlation survive quantitative bias corrections, the results would provide direct observational support for radial drift of large grains, strong vertical settling of mm-sized dust, and the dominant role of stellar gravity in setting vertical structure. The uniform analysis of a sample of inclined systems supplies new dynamical mass estimates for most targets and highlights systematic differences in apparent sizes between inclination regimes. These are useful empirical constraints for disk evolution models.

major comments (2)
  1. [Abstract and radial size measurements] Abstract and radial-extent results: The majority ordering Rgas > Rdust,micron > Rdust,mm for 11/14 disks is extracted from apparent major-axis sizes in 12CO moment maps, scattered-light images, and 0.9 mm continuum images. Because 12CO(3-2) is optically thick and the systems are highly inclined, line-of-sight integration, beam smearing, and unknown flaring can systematically alter the measured radii; the text acknowledges that inclined disks appear less CO-extended than face-on samples but does not provide deprojected radii or radiative-transfer forward models to test whether the ordering survives 20-30% biases.
  2. [Dynamical mass estimates and vertical structure] Dynamical-mass and aspect-ratio analysis: The reported anti-correlation between dynamical mass (from PV diagrams) and aspect ratio assumes Keplerian rotation and that the measured vertical extents accurately trace intrinsic heights after projection. In near-edge-on geometries the line-of-sight integration couples radial and vertical structure, so both the mass estimates and the aspect-ratio values entering the correlation require validation against synthetic observations or additional kinematic modeling.
minor comments (3)
  1. [Abstract and results] The abstract and results sections report clear trends but do not quote uncertainties, formal correlation coefficients, or p-values for the anti-correlation or the 11/14 fraction; adding these would strengthen the quantitative claims.
  2. [Results] A summary table listing measured Rgas, Rdust,micron, Rdust,mm, Hgas, Hdust,mm, dynamical mass, and aspect ratio for each of the 14 disks (with uncertainties) is missing and would improve readability and reproducibility.
  3. [Introduction or sample description] The sample selection criteria for the 14 highly inclined disks are not stated; explicit inclusion of the parent sample and inclination threshold would clarify potential selection biases.

Simulated Author's Rebuttal

2 responses · 1 unresolved

We thank the referee for their constructive comments and for recognizing the potential significance of our observational results on the structure of highly inclined protoplanetary disks. We address each major comment below and indicate the revisions planned for the manuscript.

read point-by-point responses

  1. Referee: [Abstract and radial size measurements] Abstract and radial-extent results: The majority ordering Rgas > Rdust,micron > Rdust,mm for 11/14 disks is extracted from apparent major-axis sizes in 12CO moment maps, scattered-light images, and 0.9 mm continuum images. Because 12CO(3-2) is optically thick and the systems are highly inclined, line-of-sight integration, beam smearing, and unknown flaring can systematically alter the measured radii; the text acknowledges that inclined disks appear less CO-extended than face-on samples but does not provide deprojected radii or radiative-transfer forward models to test whether the ordering survives 20-30% biases.

    Authors: We thank the referee for highlighting these potential systematic effects. Our radial extents are measured from apparent major-axis sizes in a uniform manner across the 12CO moment maps, scattered-light images, and 0.9 mm continuum images to enable consistent intra-sample comparisons. The manuscript already notes that highly inclined disks appear less CO-extended than face-on samples and attributes this to optical depth effects and/or radial drift. We agree that line-of-sight integration, beam smearing, and flaring can introduce biases, and the observed ordering is based on apparent sizes. We will expand the discussion section to address these limitations and their possible impact on the reported trends in greater detail. Full deprojected radii or radiative-transfer models to quantify the biases are not included in the current analysis. revision: partial

  2. Referee: [Dynamical mass estimates and vertical structure] Dynamical-mass and aspect-ratio analysis: The reported anti-correlation between dynamical mass (from PV diagrams) and aspect ratio assumes Keplerian rotation and that the measured vertical extents accurately trace intrinsic heights after projection. In near-edge-on geometries the line-of-sight integration couples radial and vertical structure, so both the mass estimates and the aspect-ratio values entering the correlation require validation against synthetic observations or additional kinematic modeling.

    Authors: We appreciate the referee's point regarding the assumptions in our analysis. Dynamical masses were derived from position-velocity diagrams assuming Keplerian rotation, following standard practice for such data. Aspect ratios are based on apparent vertical extents. We agree that near-edge-on geometries introduce line-of-sight coupling between radial and vertical structure, which may affect both quantities. The anti-correlation is presented as an observational result underscoring the role of stellar gravity in setting vertical structure. We will revise the manuscript to include additional discussion of these assumptions and their caveats. Validation with synthetic observations and advanced kinematic modeling is noted as a useful avenue for future work. revision: partial

standing simulated objections not resolved
  • Full radiative-transfer forward models and synthetic observations to test whether the reported size ordering and dynamical mass-aspect ratio anti-correlation survive projection and optical depth biases.

Circularity Check

0 steps flagged

No significant circularity; results are direct empirical measurements

full rationale

The paper reports observational measurements of radial extents (Rgas, Rdust,micron, Rdust,mm) and vertical heights (Hgas, Hdust,mm) extracted from ALMA 12CO moment maps, 0.9 mm continuum images, and scattered-light data for 14 inclined disks, plus dynamical masses from standard PV diagrams. The reported ordering for 11/14 disks, the Hgas > Hdust,mm trend, the flux-size correlations (with and without inclination correction), and the dynamical-mass vs. aspect-ratio anti-correlation are all direct comparisons or empirical fits to these measured quantities. No equations or derivations reduce any claimed result to its inputs by construction, and the single reference to 'previous findings' on dust settling is supplementary rather than load-bearing for the new sample statistics. The analysis is therefore self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Claims rest on direct multi-wavelength imaging and standard kinematic assumptions for mass estimation; no free parameters or new entities are introduced in the abstract.

axioms (1)
  • domain assumption Disk gas follows Keplerian rotation when deriving dynamical masses from position-velocity diagrams
    Invoked for the first-time dynamical mass estimates mentioned in the abstract.

pith-pipeline@v0.9.0 · 5691 in / 1403 out tokens · 28433 ms · 2026-05-10T15:56:58.598864+00:00 · methodology

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Works this paper leans on

2 extracted references · 2 canonical work pages

  1. [1]

    L., Jensen, E

    Akeson, R. L., Jensen, E. L. N., Carpenter, J., et al. 2019, ApJ, 872, 158 Andrews, S. M. 2020, ARA&A, 58, 483 Andrews, S. M., Terrell, M., Tripathi, A., et al. 2018, ApJ, 865, 157 Angelo, I., Duchene, G., Stapelfeldt, K., et al. 2023, ApJ, 945, 130 Ansdell, M., Williams, J. P., Trapman, L., et al. 2018, ApJ, 859, 21 Artymowicz, P. & Lubow, S. H. 1994, Ap...

    work page arXiv 2019

  2. [2]

    The continuum and line fluxes are listed in Table B.1

    Appendix B: Parameters of disk-hosting companions We performed the same analyses on the disk-hosting compan- ions of the multiple systems as we did for the objects in our main sample. The continuum and line fluxes are listed in Table B.1. The position angles and inclinations are summarized in Ta- ble. B.2. The major axis sizes as well as the minor axis si...

    work page 2012