Pith. sign in

REVIEW 4 major objections 5 minor 87 references

ALMA Observations of Peculiar Embedded Icy Objects

T0 review · 4 major / 5 minor · reviewed 2026-08-10 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read Two isolated icy objects show compact, shocked gas that matches no known class of interstellar ice source.

desk verdict Solid ALMA follow-up of two puzzling IR objects; the new-class claim is plausible but leans on a couple of shaky assumptions, worth a referee. read the letter →

arxiv 2501.05008 v1 pith:QSNRLPE7 submitted 2025-01-09 astro-ph.GA astro-ph.EPastro-ph.SR

Takashi Shimonishi , Takashi Onaka , Itsuki Sakon This is my paper · ORCID
classification astro-ph.GAastro-ph.EPastro-ph.SR
keywords interstellaricesAKARIsurveyALMACO(3-2)emissionSiO(8-7)shockedgasembeddedice-absorptionsourcesGalacticplane
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

Two compact infrared sources discovered serendipitously by the AKARI Galactic-plane survey show deep water-ice and silicate absorption yet have spectral energy distributions peaking near 5 microns, unlike standard embedded young stellar objects. This paper uses ALMA observations to show that both sources emit compact CO(3-2) and SiO(8-7) lines with high SiO/CO column ratios of about $10^{-3}$, broad line widths of 8 to 14 km/s, no detectable dust continuum, and line-of-sight velocities separated from all surrounding gas. The authors argue that this combination cannot easily be accounted for by any known interstellar ice-absorption source, including embedded protostars, background stars behind dense clouds, or OH/IR stars, and that the objects may represent a previously unknown type of isolated icy object. If correct, the result would expand the census of ice-bearing environments in the Galaxy beyond star-forming regions and dense clouds.

What carries the argument

The argument rests on two quantitative links. First, the SiO/CO column density ratio is estimated from optically thin, local-thermal-equilibrium fits to the CO(3-2) and SiO(8-7) integrated intensities; the resulting ratios near $10^{-3}$ are orders of magnitude above dark-cloud and protostellar-envelope values and overlap the ranges seen in shocked gas and oxygen-rich AGB envelopes. Second, the source size is bounded by comparing three independent column-density estimates: roughly 2 x $10^{23}$ $cm^{-2}$ from infrared dust and ice absorption, about $10^{19}$ $cm^{-2}$ from CO emission, and less than about 5 x $10^{21}$ $cm^{-2}$ from the dust continuum non-detection. Matching the infrared column density with the CO data requires about $10^{4}$ beam dilution, placing the emitting region near 100 au at the assumed kinematic distances, while the continuum limit allows up to roughly 1000 au. This compact size is what distinguishes the objects from extended dark clouds and supports the proposed isolated compact icy-object interpretation.

What would settle it

Resolve the CO(3-2) emission from one of the objects at a few tens of au resolution, or measure an optically thin isotopologue such as 13CO(3-2) to test whether the CO is optically thick; if the CO-emitting region is resolved and larger than about 1000 au, or if the CO optical depth is large, the compact-source interpretation would collapse.

Watch

Extended reading notes

Core claim

The paper claims that two AKARI-discovered infrared point sources, previously known only by their deep dust and ice absorption features and unusual 5-micron-peaked SEDs, are associated with very compact molecular gas that is kinematically isolated from the surrounding interstellar medium. ALMA detects CO(3-2) and SiO(8-7) emission at the infrared positions of both objects, with SiO/CO column density ratios of (2-4) x $10^{-3}$ for Object 1 and (0.9-3) x $10^{-3}$ for Object 2, FWHM line widths of 8-14 km/s, systemic velocities near -26 and +29 km/s, and no submillimeter continuum at a 1-$\sigma$ level of about 0.1 mJy/beam. The authors derive source sizes of roughly 100-1000 au by comparing the H2 column density from infrared absorption (about 2 x $10^{23}$ $cm^{-2}$) with the CO emission and continuum upper limits, interpreting the discrepancy as extreme beam dilution. They conclude that these properties cannot be easily explained by any known interstellar ice-absorption source and may reveal a previously unknown class of isolated, compact, shocked icy objects.

Load-bearing premise

The 100-1000 au source-size interpretation depends on the assumption that the H2 column density derived from infrared dust and ice absorption is correct and that the CO(3-2) emission is optically thin, so the roughly 10,000-fold apparent column deficit is attributed entirely to beam dilution.

Editorial extensions

If this is right

  • The detected SiO/CO ratios, (2-4) x 10^-3 and (0.9-3) x 10^-3, place both objects in the shocked-gas regime rather than in quiescent dark clouds or protostellar envelopes.
  • The broad 8-14 km/s line widths imply highly non-thermal, turbulent or shocked molecular gas around both sources.
  • With no dust continuum detected despite A_V near 100 mag, the emitting region must be far smaller than the 0.8-arcsecond beam, yielding physical sizes of roughly 100-1000 au at the assumed distances of 9.3 and 13.4 kpc.
  • The LSR velocities near -26 and +29 km/s, together with the 3.3-arcminute sky separation, indicate that the two objects are isolated and kinematically unrelated to each other and to the surrounding line-of-sight CO gas.
  • The full set of properties rules out the known classes considered by the authors, so the objects may represent a previously unknown or rare type of isolated embedded icy source.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the inferred 100-1000 au sizes are correct, the objects would be comparable in scale to protoplanetary disks, yet their lack of mid- and far-infrared excess would require an unusually faint or heavily obscured central heating source; high-resolution SiO imaging could look for jet or disk morphology that tests this.
  • The paper's submillimeter data alone cannot exclude an oxygen-rich AGB interpretation, so targeted searches for SiO masers, infrared variability, or the absence of volatile ice species like CO2 and CH3OH in OH/IR stars could cleanly separate an evolved-star explanation from the proposed compact cloud scenario.
  • The discovery of only two such objects in 22 surveyed fields suggests a low space density, and upcoming near-infrared spectroscopic surveys could systematically search for 5-micron-peaked, ice-absorbed point sources to measure what fraction of the Galaxy's ice reservoir hides in isolated compact regions.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. The paper reports ALMA 12m+ACA observations of two infrared point sources (Object 1 and Object 2) discovered serendipitously by AKARI, which show deep ice and silicate absorption features but are located away from known star-forming regions and dense clouds. The authors detect compact, unresolved CO(3-2) and SiO(8-7) emission at the infrared positions, with broad line widths (8-14 km/s), systemic velocities distinct from surrounding CO clouds, and no submillimeter continuum. They derive SiO/CO column density ratios of about 10^-3, interpret these as evidence for shocked gas, estimate kinematic distances of ~9-13 kpc and luminosities of ~500-750 L_sun, and infer source sizes of ~74-90 au by invoking beam dilution to reconcile the CO-derived column with the much larger H2 column from infrared dust/ice absorption. They argue that the combination of deep ice absorption, compact size, SiO-bearing broad emission, and isolation cannot easily be explained by known classes of interstellar ice-absorption sources (embedded YSOs, edge-on disks, background field stars, or OH/IR stars) and may represent a previously unknown type of isolated icy object.

Significance. If the interpretation holds, the paper would present a genuinely unusual class of compact, isolated, ice-rich objects with associated shocked molecular gas, potentially relevant to the inventory of ice reservoirs and isolated substellar/disk-like structures in the Galaxy. The observations are new and the CO(3-2) detections appear robust, and the paper includes useful appendices (A-C) describing the column-density and size derivations, as well as a candid discussion of the rarity of such objects and the difficulty of excluding OH/IR stars based on submillimeter data alone. The main value is as a discovery paper; however, the central claim rests on a few model-dependent inferences, particularly the marginal Object 2 SiO detection, the LTE/optically-thin assumption for the SiO/CO ratio, and the beam-dilution-based source size estimate.

major comments (4)
  1. [Table 1 and Sect. 3] The SiO(8-7) detection toward Object 2 is marginal: Table 1 reports T_br = 0.10 ± 0.04 K and ∫T_br dV = 0.9 ± 0.3 K km/s, i.e., ~2.5σ and ~3σ, respectively. Since Object 2's SiO/CO ratio is one of the two measurements supporting the 'SiO-dominated broad molecular line emission' characterization in the abstract and Section 5, this detection should not be presented as secure. Please either re-analyze with a more conservative noise estimate, explicitly label the line as tentative and exclude it from the ratio, or report the Object 2 SiO/CO value as an upper limit.
  2. [Sect. 4.2 and Eq. (A1)] The SiO/CO ratio is derived assuming LTE and optically thin emission with Trot = 20-50 K. The exclusion of Trot > 80 K based on CH3OH, SO, and SO2 non-detections is not compelling: those species may simply be underabundant in a warm gas phase, and their non-detection does not directly constrain the CO/SiO excitation temperature. More importantly, if CO(3-2) is optically thick—plausible given the low brightness temperatures and the small inferred source size—N_CO is underestimated and the SiO/CO ratio could be lower by an order of magnitude. The paper should quantify how the ratio changes under these alternatives or soften the shocked-gas interpretation accordingly.
  3. [Sect. 4.5 and Table 3] The source sizes of 74 au and 90 au are not measured quantities but the result of requiring consistency between the H2 column density from dust/ice absorption (Appendix B, which also assumes the same absorption depth for Object 2 as for Object 1) and an optically-thin CO column, with all discrepancy attributed to beam dilution. The uncertainties associated with the AV-to-NH2 conversion, the factor-of-two doubling, the CO/H2 ratio, and the optically-thin assumption are not propagated, and the 'consistency' with the continuum-based upper limit does not validate these specific sizes because both calculations are anchored to the same NH2. Please present the continuum-based constraint (source size <~1000 au) as the robust result and describe the 100 au scale as a model-dependent possibility rather than a firm measurement.
  4. [Sect. 4.4] The far kinematic distance (9.3 kpc) is adopted for Object 1 solely to make its luminosity and inferred physical scale comparable to Object 2, and the same 'similarity' is later used as evidence that the two objects belong to a common class. This introduces a partially circular element. At the near kinematic distance (2.0 kpc), Object 1 would have L ≈ 30 L_sun and a correspondingly smaller physical size. The abstract and conclusions should state explicitly that the quoted luminosities and source sizes assume the far-distance solution for Object 1, or present both distance solutions and their consequences.
minor comments (5)
  1. [Sect. 3] In the sentence 'Their FWHMs are large than those of observed in quiescent dark clouds', 'large than' should be 'larger than'.
  2. [Sect. 3] The statement 'No other emission line was detected although the present spectral setup covers transitions ...' would benefit from explicitly noting the rms noise level and that upper limits are not tabulated, to avoid the impression that the non-detections are more constraining than they are.
  3. [Sect. 4.5] The closing sentence of Section 4.5, 'The point-like and faint emission of CO, as well as the non-detection of the dust emission, would suggest that the physical size of Object 1 and 2 is around 100-1000 au', is in tension with the earlier statement that the CO-based sizes are 74 au and 90 au; please harmonize these statements.
  4. [Abstract and Sect. 5] The phrase 'SiO-dominated broad molecular line emission' overstates the observations, since the integrated SiO intensity is lower than that of CO in both objects and the Object 2 SiO detection is marginal; consider phrasing such as 'SiO-bearing broad molecular line emission' or 'enhanced SiO/CO ratio'.
  5. [References] The reference to Boogert et al. (2015) is listed as 'ArXiv e-prints' in the reference list; please update to the published citation (ARA&A, 53, 541).

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the ALMA line ratios and source-size estimates rest on new observations and independent consistency checks, not on fitted parameters or self-citation loops.

full rationale

The paper's central claims are based on new ALMA measurements of CO(3-2) and SiO(8-7), with column densities computed from the standard LTE optically-thin formula (Eq. A1) using observed integrated intensities. The SiO/CO ratio is then compared with literature values for shocks, envelopes, dark clouds, and AGB stars; this is an external benchmark, not a self-referential fit. The source-size estimate in Section 4.5 is a consistency argument: the IR-absorption column density and the CO-emission column density differ by a factor of ~10^4, and the authors explicitly attribute this to beam dilution. This is a model-dependent inference, but it is not circular because the two column estimates come from independent data sets, and the resulting size is cross-checked against an independent continuum-based upper limit. Self-citations, notably Onaka et al. (2021), provide the discovery photometry and infrared spectra; these are prior observational measurements, not an assumption of the present conclusion. The paper also candidly states that OH/IR stars cannot be fully ruled out from submillimeter data alone and calls for future higher-resolution observations, which further indicates that the argument is not forced by construction. Potential weaknesses, such as the ~3-sigma SiO detection in Object 2 and the adopted LTE/optically-thin and Trot assumptions, are scientific uncertainties rather than circularity.

Assumptions & free parameters 3 free parameters · 6 assumptions · 0 invented entities

The central claims rest on standard astrophysical conversion factors and the assumed distances. No new particles, forces, or physical entities are introduced. The most consequential assumptions are the adopted rotational/dust temperatures and the beam dilution interpretation.

free parameters (3)
  • Rotational temperature Trot for column density = 20-50 K (alternative 10 K)
    Assumed range for CO and SiO LTE column densities; directly affects the NSiO/NCO ratio, which is central to the shocked-gas interpretation.
  • Dust temperature Td for continuum upper limit = 20-50 K
    Used in Eq. C4 to convert the continuum upper limit to an H2 column density, affecting the source size upper limit in Table 3.
  • Adopted distance for Object 1 = 9.3 kpc (far) instead of 2.0 kpc (near)
    The paper assumes the far distance because of similarity to Object 2, changing the luminosity from 30 Lsun to 750 Lsun and the physical scale of the source.
assumptions (6)
  • domain assumption Molecular lines are optically thin and in LTE
    Column densities in Appendix A assume optically thin LTE emission, which is standard for these high-lying transitions but unverified for these sources.
  • domain assumption AV to NH2 conversion with NH2/AV = 7.3e20 cm^-2 mag^-1 and doubling of foreground AV
    Section B states that infrared absorption probes only the foreground component, so the derived AV is doubled to compare with submillimeter total column density.
  • domain assumption Standard CO/H2 abundance ratio of 1e-4
    Used in Section 4.5 to convert the CO column density to an H2 column density, assuming solar metallicity.
  • domain assumption Kinematic distance calculator based on Reid et al. (2014) Galactic parameters
    Section 4.3 estimates distances from LSR velocities assuming the objects participate in Galactic rotation.
  • domain assumption Dust opacity from Ossenkopf and Henning (1994) for thick ice mantles at 853 micron
    Used in Eq. C4 to convert the continuum upper limit into an H2 column density.
  • ad hoc to paper Same ice absorption depth for Object 2 as Object 1
    Section 4.5 states this assumption because Object 2's absorption bottom is below the noise level, and it directly affects the NH2 estimate for Object 2.

how reviews work

0 comments
Cite this review

Pith. "Pith review of ALMA Observations of Peculiar Embedded Icy Objects." pith.science (2026). https://pith.science/paper/QSNRLPE7

@misc{pith2026250105008,
  author       = {Pith},
  title        = {Pith review of: ALMA Observations of Peculiar Embedded Icy Objects},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/QSNRLPE7}},
  note         = {Machine review of arXiv:2501.05008}
}
read the original abstract

We report the results of molecular line observations with the Atacama Large Millimeter/submillimeter Array (ALMA) towards two peculiar icy objects, which were discovered serendipitously by infrared spectroscopic survey of the Galactic plane with the AKARI satellite. Previous infrared observations have reported that both objects show deep ice and dust absorption features that are often seen in embedded young stellar objects (YSOs) or background stars sitting behind dense clouds, however, they are located neither in known star-forming regions nor in known dense clouds. Their infrared spectral energy distributions (SEDs) show a peak around 5 micron, which are incompatible with existing SED models of typical embedded YSOs. The present ALMA observations have detected compact emission of CO(3-2) and SiO(8-7) at the positions of the icy objects. The observed large column ratios of gas-phase SiO/CO (~10^-3) in both objects, as well as their broad line widths (8-14 km/s), imply that they are associated with shocked gas. Although a large dust extinction (Av ~100 mag) is expected from their deep dust/ice absorption, no dust continuum emission is detected, which would suggest a large beam dilution effect due to their compact source sizes. Their systemic velocities are clearly separated from the surrounding CO clouds, suggesting that they are isolated. The characteristics of their SEDs, the presence of deep dust/ice absorption features, compact source size, and SiO-dominated broad molecular line emission, cannot easily be accounted for by any of known interstellar ice-absorption sources. They may represent a previously unknown type of isolated icy objects.

Figures

Figures reproduced from arXiv: 2501.05008 by the authors.

Figure 1
Figure 1. Direction of Object 1 and 2 (solid yellow line). The green squares represent their possible locations based on the kine￾matic distance estimates (see Section 4.3 and 4.4). The background is an artist’s conception of the Milky Way (R. Hurt/NASA/JPL￾Caltech/ESO). The target objects are located in the direction toward the Crux-Scutum arm ( [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. ALMA observations of Object 1. (a) Composite two-color image (cyan: 0.61 µm, red: 2.16 µm) based on the DSS and 2MASS data. The white square indicates the field-of-view of the ALMA observations. (b) Integrated intensity distribution of CO(3–2) in a whole field-of-view (16′′). The image is constructed by integrating the spectral data in a velocity range from −75 to −40 km s−1 . The panel (e) shows the CO spectrum ext… view at source ↗
Figure 3
Figure 3. The same as in [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figures from the paper (2 more)
Figure 4
Figure 4. Figure 4: shows SEDs of Object 1 and 2 together with the typical SEDs of Class I and Class II YSOs. Also plotted is the synthesized spectrum of a reddened star with an arbitrary scaled flux. The spectrum was calculated by applying the in￾terstellar extinction curve of Draine (20…
Figure 5
Figure 5. Figure 5: ALMA CO(3–2) channel maps for the region around Object 1 (a) and 2 (b). The plotted velocity ranges are from −75 to −15 km s−1 with an interval of 5 km s−1 for Object 1, and from −75 to 45 km s−1 with an interval of 10 km s−1 for Object 2. The integrated velocity range…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

87 extracted references · 23 canonical work pages

  1. [1]

    _al8O`[\!<<+]!0@0 5<s:7<iNY!!#_f! !?(qA!!!!

    thebibliography [1] 20pt to REFERENCES 6pt =0pt -12pt 10pt plus 3pt =0pt =0pt =1pt plus 1pt =0pt =0pt -12pt =13pt plus 1pt =20pt =13pt plus 1pt \@M =10000 =-1.0em =0pt =0pt 0pt =0pt =1.0em @enumiv\@empty 10000 10000 `\.\@m \@noitemerr \@latex@warning Empty `thebibliography' environment \@ifnextchar \@reference \@latexerr Missing key on reference command E...

    work page arXiv 2021

  2. [2]

    2012, , 538, A57, 10.1051/0004-6361/201015999

    Aikawa , Y., Kamuro , D., Sakon , I., et al. 2012, , 538, A57, 10.1051/0004-6361/201015999

    doi:10.1051/0004-6361/201015999 2012

  3. [3]

    Ashby , M. L. N., Hora , J. L., Lakshmipathaiah , K., et al. 2023, , 949, 105, 10.3847/1538-4357/acc86b

    work page doi:10.3847/1538-4357/acc86b 2023

  4. [4]

    1991, , 243, L21

    Bachiller , R., Martin-Pintado , J., & Fuente , A. 1991, , 243, L21

    1991

  5. [5]

    G., Tan , J

    Bisbas , T. G., Tan , J. C., & Tanaka , K. E. I. 2021, , 502, 2701, 10.1093/mnras/stab121

    doi:10.1093/mnras/stab121 2021

  6. [6]

    C., Savage , B

    Bohlin , R. C., Savage , B. D., & Drake , J. F. 1978, , 224, 132, 10.1086/156357

    doi:10.1086/156357 1978

  7. [7]

    2015, ArXiv e-prints

    Boogert , A., Gerakines , P., & Whittet , D. 2015, ArXiv e-prints. 1501.05317

    arXiv 2015

  8. [8]

    Boogert , A. C. A., & Ehrenfreund , P. 2004, in Astronomical Society of the Pacific Conference Series, Vol. 309, Astrophysics of Dust, ed. A. N. Witt, G. C. Clayton, & B. T. Draine , 547

    2004

Show all 87 references
  1. [9]

    Boogert , A. C. A., Huard , T. L., Cook , A. M., et al. 2011, , 729, 92, 10.1088/0004-637X/729/2/92

    2011 doi

  2. [10]

    1994, , 285, 247

    Bujarrabal , V., Fuente , A., & Omont , A. 1994, , 285, 247

    1994

  3. [11]

    2022, , 134, 114501, 10.1088/1538-3873/ac9642

    CASA Team , Bean , B., Bhatnagar , S., et al. 2022, , 134, 114501, 10.1088/1538-3873/ac9642

    2022 doi

  4. [12]

    Cox , A. N. 2000, Allen's astrophysical quantities (Springer)

    2000

  5. [13]

    F., Hogerheijde , M

    Crapsi , A., van Dishoeck , E. F., Hogerheijde , M. R., Pontoppidan , K. M., & Dullemond , C. P. 2008, , 486, 245, 10.1051/0004-6361:20078589

    2008 doi

  6. [14]

    R., et al

    Dartois , E., Schutte , W., Geballe , T. R., et al. 1999, , 342, L32

    1999

  7. [15]

    2010, , 523, A18, 10.1051/0004-6361/200913771

    De Beck , E., Decin , L., de Koter , A., et al. 2010, , 523, A18, 10.1051/0004-6361/200913771

    2010 doi

  8. [16]

    2005, , 57, S1, 10.1093/pasj/57.sp1.S1

    Dobashi , K., Uehara , H., Kandori , R., et al. 2005, , 57, S1, 10.1093/pasj/57.sp1.S1

    2005 doi

  9. [17]

    Draine , B. T. 2003, , 41, 241, 10.1146/annurev.astro.41.011802.094840

    2003 arXiv

  10. [18]

    1999, , 341, L47, 10.48550/arXiv.astro-ph/9811263

    Duari , D., Cherchneff , I., & Willacy , K. 1999, , 341, L47, 10.48550/arXiv.astro-ph/9811263

    1999 doi arXiv

  11. [19]

    2024, , 167, 72, 10.3847/1538-3881/ad152b

    Dutta , S., Lee , C.-F., Johnstone , D., et al. 2024, , 167, 72, 10.3847/1538-3881/ad152b

    2024 doi

  12. [20]

    P., Price , S

    Egan , M. P., Price , S. D., & Kraemer , K. E. 2003, in American Astronomical Society Meeting Abstracts, Vol. 203, American Astronomical Society Meeting Abstracts, 57.08

    2003

  13. [21]

    A., Duchene , G., & Stahler , S

    Ellithorpe , E. A., Duchene , G., & Stahler , S. W. 2019, , 885, 64, 10.3847/1538-4357/ab4651

    2019 doi

  14. [22]

    2014, , 563, A97, 10.1051/0004-6361/201322541

    Gerner , T., Beuther , H., Semenov , D., et al. 2014, , 563, A97, 10.1051/0004-6361/201322541

    2014 doi

  15. [23]

    L., Whittet , D

    Gibb , E. L., Whittet , D. C. B., Boogert , A. C. A., & Tielens , A. G. G. M. 2004, , 151, 35, 10.1086/381182

    2004 doi

  16. [24]

    2003, , 411, 123, 10.1051/0004-6361:20031068

    Gonz \'a lez Delgado , D., Olofsson , H., Kerschbaum , F., et al. 2003, , 411, 123, 10.1051/0004-6361:20031068

    2003 doi

  17. [25]

    2024, The Journal of Open Source Software, 9, 7023, 10.21105/joss.07023

    Gordon , K. 2024, The Journal of Open Source Software, 9, 7023, 10.21105/joss.07023

    2024 doi

  18. [26]

    Groenewegen , M. A. T., Wood , P. R., Sloan , G. C., et al. 2007, , 376, 313, 10.1111/j.1365-2966.2007.11428.x

    2007

  19. [27]

    M., & Hony , S

    Heras , A. M., & Hony , S. 2005, , 439, 171, 10.1051/0004-6361:20042296

    2005 doi

  20. [28]

    2017, , 467, 699, 10.1093/mnras/stx118

    Hirashita , H., & Harada , N. 2017, , 467, 699, 10.1093/mnras/stx118

    2017 doi

  21. [29]

    K., Fukagawa , M., et al

    Honda , M., Inoue , A. K., Fukagawa , M., et al. 2009, , 690, L110, 10.1088/0004-637X/690/2/L110

    2009 doi

  22. [30]

    2016, , 821, 2, 10.3847/0004-637X/821/1/2

    Honda , M., Kudo , T., Takatsuki , S., et al. 2016, , 821, 2, 10.3847/0004-637X/821/1/2

    2016 doi

  23. [31]

    M., Molster , F

    Hony , S., Heras , A. M., Molster , F. J., & Smolders , K. 2009, , 501, 609, 10.1051/0004-6361/200912017

    2009 doi

  24. [32]

    C., & Maloney , P

    Imanishi , M., Dudley , C. C., & Maloney , P. R. 2006, , 637, 114, 10.1086/498391

    2006 doi

  25. [33]

    2008, , 60, S489, 10.1093/pasj/60.sp2.S489

    Imanishi , M., Nakagawa , T., Ohyama , Y., et al. 2008, , 60, S489, 10.1093/pasj/60.sp2.S489

    2008 doi

  26. [34]

    Justtanont , K., Olofsson , G., Dijkstra , C., & Meyer , A. W. 2006, , 450, 1051, 10.1051/0004-6361:20054569

    2006 doi

  27. [35]

    J., Tielens , A

    Justtanont , K., Skinner , C. J., Tielens , A. G. G. M., Meixner , M., & Baas , F. 1996, , 456, 337, 10.1086/176655

    1996 doi

  28. [36]

    2003, , 407, 609, 10.1051/0004-6361:20030701

    Kemper , F., Stark , R., Justtanont , K., et al. 2003, , 407, 609, 10.1051/0004-6361:20030701

    2003 doi

  29. [37]

    A., Tsutsumi , T., Brogan , C

    Kepley , A. A., Tsutsumi , T., Brogan , C. L., et al. 2020, , 132, 024505, 10.1088/1538-3873/ab5e14

    2020 doi

  30. [38]

    Knez , C., Boogert , A. C. A., Pontoppidan , K. M., et al. 2005, , 635, L145, 10.1086/499584

    2005 doi

  31. [39]

    Larson , R. B. 1981, , 194, 809, 10.1093/mnras/194.4.809

    1981 doi

  32. [40]

    Lepine , J. R. D., Ortiz , R., & Epchtein , N. 1995, , 299, 453

    1995

  33. [41]

    A., van Loon , J

    Matsuura , M., Zijlstra , A. A., van Loon , J. T., et al. 2002, , 580, L133, 10.1086/345680

    2002 doi

  34. [42]

    K., Rocha , W

    McClure , M. K., Rocha , W. R. M., Pontoppidan , K. M., et al. 2023, Nature Astronomy, 7, 431, 10.1038/s41550-022-01875-w

    2023 doi

  35. [43]

    P., Waters , B., Schiebel , D., Young , W., & Golap , K

    McMullin , J. P., Waters , B., Schiebel , D., Young , W., & Golap , K. 2007, in Astronomical Society of the Pacific Conference Series, Vol. 376, Astronomical Data Analysis Software and Systems XVI, ed. R. A. Shaw , F. Hill , & D. J. Bell , 127

    2007

  36. [44]

    2016, , 591, A149, 10.1051/0004-6361/201526380

    Molinari , S., Schisano , E., Elia , D., et al. 2016, , 591, A149, 10.1051/0004-6361/201526380

    2016 doi

  37. [45]

    A., Fraser , H

    Noble , J. A., Fraser , H. J., Aikawa , Y., Pontoppidan , K. M., & Sakon , I. 2013, , 775, 85, 10.1088/0004-637X/775/2/85

    2013 doi

  38. [46]

    A., Fraser , H

    Noble , J. A., Fraser , H. J., Pontoppidan , K. M., & Craigon , A. M. 2017, , 467, 4753, 10.1093/mnras/stx329

    2017 doi

  39. [47]

    I., Boogert , A

    \"O berg , K. I., Boogert , A. C. A., Pontoppidan , K. M., et al. 2011, , 740, 109, 10.1088/0004-637X/740/2/109

    2011 doi

  40. [48]

    A., et al

    Olofsson , H., Khouri , T., Sargent , B. A., et al. 2022, , 665, A82, 10.1051/0004-6361/202244053

    2022 doi

  41. [49]

    2002, , 388, 573, 10.1051/0004-6361:20020574

    Onaka , T., de Jong , T., & Yamamura , I. 2002, , 388, 573, 10.1051/0004-6361:20020574

    2002 doi

  42. [50]

    2021, , 916, 75, 10.3847/1538-4357/ac0531

    Onaka , T., Kimura , T., Sakon , I., & Shimonishi , T. 2021, , 916, 75, 10.3847/1538-4357/ac0531

    2021 doi

  43. [51]

    2022, , 941, 190, 10.3847/1538-4357/ac9b15

    Onaka , T., Sakon , I., & Shimonishi , T. 2022, , 941, 190, 10.3847/1538-4357/ac9b15

    2022 doi

  44. [52]

    2007, , 59, 401

    Onaka , T., Matsuhara , H., Wada , T., et al. 2007, , 59, 401. 0705.4144

    2007 arXiv

  45. [53]

    1994, , 291, 943

    Ossenkopf , V., & Henning , T. 1994, , 291, 943

    1994

  46. [54]

    Peretto , N., & Fuller , G. A. 2009, , 505, 405, 10.1051/0004-6361/200912127

    2009 doi

  47. [55]

    M., Dullemond , C

    Pontoppidan , K. M., Dullemond , C. P., van Dishoeck , E. F., et al. 2005, , 622, 463, 10.1086/427688

    2005 doi

  48. [56]

    M., Boogert , A

    Pontoppidan , K. M., Boogert , A. C. A., Fraser , H. J., et al. 2008, , 678, 1005, 10.1086/533431

    2008 doi

  49. [57]

    J., Menten , K

    Reid , M. J., Menten , K. M., Zheng , X. W., et al. 2009, , 700, 137, 10.1088/0004-637X/700/1/137

    2009 doi

  50. [58]

    J., Menten , K

    Reid , M. J., Menten , K. M., Brunthaler , A., et al. 2014, , 783, 130, 10.1088/0004-637X/783/2/130

    2014 doi

  51. [59]

    C., Mac \' as , E., et al

    Ribas , \'A ., Espaillat , C. C., Mac \' as , E., et al. 2017, , 849, 63, 10.3847/1538-4357/aa8e99

    2017 doi

  52. [60]

    2006, , 365, 303, 10.1111/j.1365-2966.2005.09715.x

    Risaliti , G., Maiolino , R., Marconi , A., et al. 2006, , 365, 303, 10.1111/j.1365-2966.2005.09715.x

    2006

  53. [61]

    Rocha , W. R. M., van Dishoeck , E. F., Ressler , M. E., et al. 2024, , 683, A124, 10.1051/0004-6361/202348427

    2024 doi

  54. [62]

    2009, , 703, 270, 10.1088/0004-637X/703/1/270

    Sajina , A., Spoon , H., Yan , L., et al. 2009, , 703, 270, 10.1088/0004-637X/703/1/270

    2009 doi

  55. [63]

    M., Pineau des Forets , G., & Flower , D

    Schilke , P., Walmsley , C. M., Pineau des Forets , G., & Flower , D. R. 1997, , 321, 293

    1997

  56. [64]

    2010, , 514, A12, 10.1051/0004-6361/200913815

    Shimonishi , T., Onaka , T., Kato , D., et al. 2010, , 514, A12, 10.1051/0004-6361/200913815

    2010 doi

  57. [65]

    F., Cutri , R

    Skrutskie , M. F., Cutri , R. M., Stiening , R., et al. 2006, , 131, 1163, 10.1086/498708

    2006 doi

  58. [66]

    Spoon , H. W. W., Keane , J. V., Tielens , A. G. G. M., et al. 2002, , 385, 1022, 10.1051/0004-6361:20020147

    2002 doi

  59. [67]

    Spoon , H. W. W., Moorwood , A. F. M., Pontoppidan , K. M., et al. 2003, , 402, 499, 10.1051/0004-6361:20030290

    2003 doi

  60. [68]

    A., McClure , M

    Sturm , J. A., McClure , M. K., Beck , T. L., et al. 2023, , 679, A138, 10.1051/0004-6361/202347512

    2023 doi

  61. [69]

    2013, , 762, 113, 10.1088/0004-637X/762/2/113

    Suh , K.-W., & Kwon , Y.-J. 2013, , 762, 113, 10.1088/0004-637X/762/2/113

    2013 doi

  62. [70]

    J., Kemper , F., Barlow , M

    Sylvester , R. J., Kemper , F., Barlow , M. J., et al. 1999, , 352, 587

    1999

  63. [71]

    Tabone , B., Godard , B., Pineau des For \^e ts , G., Cabrit , S., & van Dishoeck , E. F. 2020, , 636, A60, 10.1051/0004-6361/201937383

    2020 doi

  64. [72]

    2010, , 522, A91, 10.1051/0004-6361/201015158

    Tafalla , M., Santiago-Garc \' a , J., Hacar , A., & Bachiller , R. 2010, , 522, A91, 10.1051/0004-6361/201015158

    2010 doi

  65. [73]

    T., Kobayashi , N., et al

    Terada , H., Tokunaga , A. T., Kobayashi , N., et al. 2007, , 667, 303, 10.1086/520951

    2007 doi

  66. [74]

    Tielens , A. G. G. M., Allamandola , L. J., Bregman , J., et al. 1984, , 287, 697, 10.1086/162728

    1984 doi

  67. [75]

    2018, , 609, A63, 10.1051/0004-6361/201731298

    Van de Sande , M., Decin , L., Lombaert , R., et al. 2018, , 609, A63, 10.1051/0004-6361/201731298

    2018 doi

  68. [76]

    J., van der Heiden , R., & van Schooneveld , C

    van Langevelde , H. J., van der Heiden , R., & van Schooneveld , C. 1990, , 239, 193

    1990

  69. [77]

    Whittet , D. C. B., Bode , M. F., Longmore , A. J., et al. 1988, , 233, 321

    1988

  70. [78]

    Whittet , D. C. B., Gerakines , P. A., Hough , J. H., & Shenoy , S. S. 2001, , 547, 872, 10.1086/318421

    2001 doi

  71. [79]

    Whittet , D. C. B., Shenoy , S. S., Bergin , E. A., et al. 2007, , 655, 332, 10.1086/509772

    2007 doi

  72. [80]

    P., & Cieza , L

    Williams , J. P., & Cieza , L. A. 2011, , 49, 67, 10.1146/annurev-astro-081710-102548

    2011 doi

  73. [81]

    L., Eisenhardt , P

    Wright , E. L., Eisenhardt , P. R. M., Mainzer , A. K., et al. 2010, , 140, 1868, 10.1088/0004-6256/140/6/1868

    2010 doi

  74. [82]

    2015, , 807, 29, 10.1088/0004-637X/807/1/29

    Yamagishi , M., Kaneda , H., Ishihara , D., et al. 2015, , 807, 29, 10.1088/0004-637X/807/1/29

    2015 doi

  75. [83]

    2013, , 773, L37, 10.1088/2041-8205/773/2/L37

    ---. 2013, , 773, L37, 10.1088/2041-8205/773/2/L37

    2013 doi

  76. [84]

    2017, Introduction to Astrochemistry: Chemical Evolution from Interstellar Clouds to Star and Planet Formation (Springer), 10.1007/978-4-431-54171-4

    Yamamoto , S. 2017, Introduction to Astrochemistry: Chemical Evolution from Interstellar Clouds to Star and Planet Formation (Springer), 10.1007/978-4-431-54171-4

    2017 doi

  77. [85]

    2000, in ESA Special Publication, Vol

    Yamamura , I., & de Jong , T. 2000, in ESA Special Publication, Vol. 456, ISO Beyond the Peaks: The 2nd ISO Workshop on Analytical Spectroscopy, ed. A. Salama, M. F. Kessler, K. Leech, & B. Schulz , 155

    2000

  78. [86]

    D., Pontoppidan , K

    Yang , Y.-L., Green , J. D., Pontoppidan , K. M., et al. 2022, , 941, L13, 10.3847/2041-8213/aca289

    2022 doi

  79. [87]

    M., Friberg , P., & Irvine , W

    Ziurys , L. M., Friberg , P., & Irvine , W. M. 1989, , 343, 201, 10.1086/167696

    1989 doi

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.