[ { "id": "authors:b2g0v-aj215", "collection": "authors", "collection_id": "b2g0v-aj215", "cite_using_url": "https://authors.library.caltech.edu/records/b2g0v-aj215", "type": "article", "title": "Constraining Properties of Dust Formed in Wolf\u2013Rayet Binary WR 112 Using Mid-infrared and Millimeter Observations", "author": [ { "family_name": "Wu", "given_name": "Donglin", "orcid": "0009-0008-8224-3140" }, { "family_name": "Han", "given_name": "Yinuo", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Williams", "given_name": "Peredur M.", "orcid": "0000-0002-8092-980X" }, { "family_name": "Onaka", "given_name": "Takashi", "orcid": "0000-0002-8234-6747" }, { "family_name": "Callingham", "given_name": "Joseph R.", "orcid": "0000-0002-7167-1819" }, { "family_name": "Hankins", "given_name": "Matthew J.", "orcid": "0000-0001-9315-8437" }, { "family_name": "Tuthill", "given_name": "Peter", "orcid": "0000-0001-7026-6291" }, { "family_name": "Lau", "given_name": "Ryan M.", "orcid": "0000-0003-0778-0321", "clpid": "Lau-Ryan-M" }, { "family_name": "Weigelt", "given_name": "Gerd", "orcid": "0000-0001-9754-2233" }, { "family_name": "Pope", "given_name": "Benjamin J. S.", "orcid": "0000-0003-2595-9114" }, { "family_name": "Richardson", "given_name": "Noel D.", "orcid": "0000-0002-2806-9339" }, { "family_name": "Moffat", "given_name": "Anthony", "orcid": "0000-0002-4333-9755" } ], "abstract": "

Binaries that host a carbon-rich Wolf–Rayet (WC) star and an OB-type companion can be copious dust producers. Yet the properties of dust, particularly the grain size distribution, in these systems remain uncertain. We present Band 6 observations of WR 112 by the Atacama Large Millimeter/submillimeter Array telescope (ALMA), which are the first millimeter observations of a WC binary system capable of resolving its dust emission. By combining ALMA observations with James Webb Space Telescope images, we were able to analyze the spatially resolved spectral energy distribution (SED) of WR 112. We found that the SEDs are consistent with emissions from hydrogen-poor amorphous carbon grains. Notably, our results also suggest that the majority of grains in the system have radii below one micrometer, and the extended dust structures are dominated by nanometer-sized grains. Among four parameterizations of the grain radius distribution that we tested, a bimodal distribution, with abundant nanometer-sized grains and a secondary population of 0.1 μ m grains, best reproduces the observed SED. This bimodal distribution helps to reconcile the previously conflicting grain size estimates reported for WR 112 and for other WC systems. We hypothesize that dust destruction mechanisms such as radiative torque disruption and radiative-driven sublimation are responsible for driving the system to the bimodal grain size distribution.

", "doi": "10.3847/1538-4357/ae31f1", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2026-03-01", "series_number": "1", "volume": "999", "issue": "1", "pages": "32" }, { "id": "authors:dq86a-7x244", "collection": "authors", "collection_id": "dq86a-7x244", "cite_using_url": "https://authors.library.caltech.edu/records/dq86a-7x244", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). IX. Gas-driven origin for the continuum arc in the debris disc of HD121617", "author": [ { "family_name": "Weber", "given_name": "P.", "orcid": "0000-0002-3354-6654" }, { "family_name": "P\u00e9rez", "given_name": "S.", "orcid": "0000-0003-2953-755X" }, { "family_name": "Baruteau", "given_name": "C.", "orcid": "0000-0002-2672-3456" }, { "family_name": "Marino", "given_name": "S.", "orcid": "0000-0002-5352-2924" }, { "family_name": "Castillo", "given_name": "F.", "orcid": "0009-0006-0290-6035" }, { "family_name": "Jankovic", "given_name": "M. R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "Pearce", "given_name": "T.", "orcid": "0000-0001-5653-5635" }, { "family_name": "Wyatt", "given_name": "M. C.", "orcid": "0000-0001-9064-5598" }, { "family_name": "Sefilian", "given_name": "A. A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Olofsson", "given_name": "J.", "orcid": "0000-0003-4475-3605" }, { "family_name": "Cataldi", "given_name": "G.", "orcid": "0000-0002-2700-9676" }, { "family_name": "Lovell", "given_name": "J. B.", "orcid": "0000-0002-4248-5443" }, { "family_name": "del Burgo", "given_name": "C.", "orcid": "0000-0002-8949-5200" }, { "family_name": "Hughes", "given_name": "A. M.", "orcid": "0000-0002-4803-6200" }, { "family_name": "Mac Manamon", "given_name": "S.", "orcid": "0000-0002-7066-8052" }, { "family_name": "Brennan", "given_name": "A.", "orcid": "0000-0002-7050-0161" }, { "family_name": "Matr\u00e0", "given_name": "L.", "orcid": "0000-0003-4705-3188" }, { "family_name": "Milli", "given_name": "J.", "orcid": "0000-0001-9325-2511" }, { "family_name": "Zawadzki", "given_name": "B.", "orcid": "0000-0001-9319-1296" }, { "family_name": "Chiang", "given_name": "E.", "orcid": "0000-0002-6246-2310" }, { "family_name": "MacGregor", "given_name": "M. A.", "orcid": "0000-0001-7891-8143" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587" }, { "family_name": "Bonduelle", "given_name": "M.", "orcid": "0009-0000-7049-8439" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Han", "given_name": "Y.", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "\u00c1.", "orcid": "0000-0001-7157-6275" }, { "family_name": "Luppe", "given_name": "P.", "orcid": "0000-0002-1018-6203" } ], "abstract": "

Context. Debris discs were long considered to be largely gas-free environments, where dynamical evolution is governed primarily by collisional fragmentation, gravitational stirring, and radiative forces. Recent detections of CO molecular line emission in debris discs demonstrate that gas is present, but its abundance and origin are still uncertain. The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) observed both the gas and dust of several debris discs at high resolution and revealed a narrow ring of gas and dust in the disc HD 121617, with an asymmetric arc-like feature that is 40% brighter than the rest of the ring.

\n

Aims. An important open question is how representative the estimated CO masses are for the total gas mass in debris discs. We aim to constrain the total gas mass in HD 121617 using numerical models under the assumption that the dust arc is produced by hydrodynamical processes involving the gas.

\n

Methods. We used the hydrodynamical code Dusty FARGO-ADSG, in which dust is modelled as Lagrangian particles. We explored the effects of radiation pressure and dust feedback, as well as of varying the total gas mass on the dynamical evolution of the system. We compared these simulations with observations via radiative transfer calculations.

\n

Results. We find that an unstable gas ring can create a size-dependent radial and azimuthal dust trap. The total gas mass dictates the efficiency of particle trapping as a function of grain size. We find that two of our models, Mgas=50 M⊕ and Mgas=5 M⊕, can simultaneously reproduce the observed arc in the ALMA band 7 continuum image and the radial outward offset of the VLT/SPHERE scattered light ring, driven by the combined effects of gas drag and radiation pressure. We further find a conservative lower limit of Mgas>2.5 M⊕ and a conservative upper limit of Mgas<250 M⊕.

\n

Conclusions. If the ALMA band 7 asymmetry is caused by gas drag, reconciling the required gas mass with the observed 12CO emission suggests the presence of significant amounts of H2, consistent with the gas being primordial, that is, long-lived remnant material from the protoplanetary disc phase. In this scenario, HD 121617 would represent a hybrid disc, bridging the protoplanetary and debris disc stages. As an arc-shaped emission can alternatively be reproduced by a planet’s gravitational forcing, future observations are crucial to distinguish between these two scenarios.

", "doi": "10.1051/0004-6361/202556855", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A203" }, { "id": "authors:g62hw-ppy43", "collection": "authors", "collection_id": "g62hw-ppy43", "cite_using_url": "https://authors.library.caltech.edu/records/g62hw-ppy43", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). VI. Asymmetries and offsets", "author": [ { "family_name": "Lovell", "given_name": "J. B.", "orcid": "0000-0002-4248-5443" }, { "family_name": "Hales", "given_name": "A. S." }, { "family_name": "Kennedy", "given_name": "G. M.", "orcid": "0000-0001-6831-7547" }, { "family_name": "Marino", "given_name": "S.", "orcid": "0000-0002-5352-2924" }, { "family_name": "Olofsson", "given_name": "J.", "orcid": "0000-0003-4475-3605" }, { "family_name": "Hughes", "given_name": "A. M.", "orcid": "0000-0002-4803-6200" }, { "family_name": "Mansell", "given_name": "E.", "orcid": "0009-0004-1433-8149" }, { "family_name": "Matthews", "given_name": "B. C.", "orcid": "0000-0003-3017-9577" }, { "family_name": "Pearce", "given_name": "T. D.", "orcid": "0000-0001-5653-5635" }, { "family_name": "Sefilian", "given_name": "A. A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587" }, { "family_name": "Zawadzki", "given_name": "B.", "orcid": "0000-0001-9319-1296" }, { "family_name": "Booth", "given_name": "M.", "orcid": "0000-0001-8568-6336" }, { "family_name": "Bonduelle", "given_name": "M.", "orcid": "0009-0000-7049-8439" }, { "family_name": "Brennan", "given_name": "A.", "orcid": "0000-0002-7050-0161" }, { "family_name": "del Burgo", "given_name": "C.", "orcid": "0000-0002-8949-5200" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Cataldi", "given_name": "G.", "orcid": "0000-0002-2700-9676" }, { "family_name": "Chiang", "given_name": "E.", "orcid": "0000-0002-6246-2310" }, { "family_name": "Fehr", "given_name": "A." }, { "family_name": "Han", "given_name": "Y.", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Henning", "given_name": "Th.", "orcid": "0000-0002-1493-300X" }, { "family_name": "Krivov", "given_name": "A. V.", "orcid": "0009-0009-4573-2612" }, { "family_name": "Luppe", "given_name": "P.", "orcid": "0000-0002-1018-6203" }, { "family_name": "Marshall", "given_name": "J. P.", "orcid": "0000-0001-6208-1801" }, { "family_name": "Mac Manamon", "given_name": "S.", "orcid": "0000-0002-7066-8052" }, { "family_name": "Milli", "given_name": "J.", "orcid": "0000-0001-9325-2511" }, { "family_name": "Mo\u00f3r", "given_name": "A.", "orcid": "0009-0001-9360-2670" }, { "family_name": "Wyatt", "given_name": "M. C.", "orcid": "0000-0001-9064-5598" }, { "family_name": "Ertel", "given_name": "S." }, { "family_name": "Jankovic", "given_name": "M. R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "\u00c1.", "orcid": "0000-0001-7157-6275" }, { "family_name": "MacGregor", "given_name": "M. A.", "orcid": "0000-0001-7891-8143" }, { "family_name": "Matr\u00e0", "given_name": "L.", "orcid": "0000-0003-4705-3188" }, { "family_name": "P\u00e9rez", "given_name": "S.", "orcid": "0000-0003-2953-755X" }, { "family_name": "Weber", "given_name": "P.", "orcid": "0000-0002-3354-6654" } ], "abstract": "

Context. Asymmetries in debris discs provide unique clues to understand the evolution and architecture of planetary systems. Previous studies of debris discs at (sub)millimetre wavelengths have suggested the presence of asymmetries in a wide variety of systems, yet the lack of sufficiently sensitive high-resolution observations means that the typical properties of debris disc asymmetries have not been studied at the population level. The aim of the ALMA survey to Resolve exoKuiper belt Substructures (ARKS) is to expand our understanding of radial and vertical dust structures, as well as gas distributions and kinematics, in debris discs. The ARKS sample of 24 highly resolved targets in ALMA’s Bands 6 and 7 (1.1–1.4 mm and 0.8–1.1 mm, respectively) provided a unique opportunity to study their asymmetries.

\n

Aims. Here, in ARKS VI, we present a systematic analysis of the asymmetries and stellocentric offsets present in the ALMA continuum data for the ARKS survey. Our aims are to (i) identify asymmetries in debris disc dust distributions, (ii) quantify debris disc asymmetry properties, and (iii) discuss the potential origins of debris disc asymmetries. This work is the first systematic analysis of asymmetries in a large sample of well-resolved discs at (sub)millimetre wavelengths.

\n

Methods. We utilised empirical methods to identify emission asymmetries (relative to disc major and minor axes, and azimuthal disc locations) and the presence of offset emission between disc centres and the locations of the host stars, via an analysis of their calibration procedures and disc properties. We associated observational asymmetry types (offset, major and/or minor axis, azimuthal) and plausible physical classes (arcs, eccentricities, and possible clumps and warps) associated with each source.

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Results. We show that there are ten systems, almost half of the ARKS sample, that host either a continuum emission asymmetry or offset emission. Three systems host offsets (HD 15115, HD 32297, and HD 109573 (HR 4796)), four host azimuthal asymmetries (HD 9672 (49 Ceti), HD 92945, HD 107146, and HD 121617), two host an asymmetry in their major axis (HD 10647 (q1 Eri), and HD 39060 (β Pic)), and one hosts an asymmetry in their minor axis (HD 61005). We attribute the offset asymmetries to non-zero eccentricities, and three of the azimuthal asymmetries to arcs. The presence of an asymmetry or offset in the ARKS sample appears to be correlated with the fractional luminosity of cold dust. We tentatively suggest that continuum asymmetries are more prevalent in CO-rich debris discs, suggesting that gas interactions may drive debris dust asymmetries. We identify seven other tentative asymmetries, including four in distinct ARKS systems and three in systems with otherwise significant asymmetries.

\n

Conclusions. This study demonstrates that debris disc asymmetries in the ARKS sample are common, and plausibly so in the wider population of debris discs at (sub)-millimetre wavelengths. This means that (sub)-millimetre asymmetries plausibly await discovery in debris discs as we probe these with higher sensitivity and resolution. Throughout, we highlight future studies to further investigate the origins of debris disc asymmetries, and build on the work presented here.

", "doi": "10.1051/0004-6361/202556568", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A200" }, { "id": "authors:gf6wb-56015", "collection": "authors", "collection_id": "gf6wb-56015", "cite_using_url": "https://authors.library.caltech.edu/records/gf6wb-56015", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). IV. CO gas imaging and overview", "author": [ { "family_name": "Mac Manamon", "given_name": "S.", "orcid": "0000-0002-7066-8052" }, { "family_name": "Matr\u00e0", "given_name": "L.", "orcid": "0000-0003-4705-3188" }, { "family_name": "Marino", "given_name": "S.", "orcid": "0000-0002-5352-2924" }, { "family_name": "Brennan", "given_name": "A.", "orcid": "0000-0002-7050-0161" }, { "family_name": "Han", "given_name": "Y.", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Jankovic", "given_name": "M. R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "Weber", "given_name": "P.", "orcid": "0000-0002-3354-6654" }, { "family_name": "Bonduelle", "given_name": "M.", "orcid": "0009-0000-7049-8439" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Cataldi", "given_name": "G.", "orcid": "0000-0002-2700-9676" }, { "family_name": "Hughes", "given_name": "A. M.", "orcid": "0000-0002-4803-6200" }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "A.", "orcid": "0000-0001-7157-6275" }, { "family_name": "Marshall", "given_name": "J. P.", "orcid": "0000-0001-6208-1801" }, { "family_name": "Matthews", "given_name": "B. C.", "orcid": "0000-0003-3017-9577" }, { "family_name": "Milli", "given_name": "J.", "orcid": "0000-0001-9325-2511" }, { "family_name": "Mo\u00f3r", "given_name": "A.", "orcid": "0009-0001-9360-2670" }, { "family_name": "\u00d6berg", "given_name": "K.", "orcid": "0000-0001-8798-1347" }, { "family_name": "P\u00e9rez", "given_name": "S.", "orcid": "0000-0003-2953-755X" }, { "family_name": "Sefilian", "given_name": "A. A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587" }, { "family_name": "Wyatt", "given_name": "M. C.", "orcid": "0000-0001-9064-5598" }, { "family_name": "Chiang", "given_name": "E.", "orcid": "0000-0002-6246-2310" }, { "family_name": "Hales", "given_name": "A. S." }, { "family_name": "Lovell", "given_name": "J. B.", "orcid": "0000-0002-4248-5443" }, { "family_name": "Luppe", "given_name": "P.", "orcid": "0000-0002-1018-6203" }, { "family_name": "MacGregor", "given_name": "M. A.", "orcid": "0000-0001-7891-8143" }, { "family_name": "Pearce", "given_name": "T.", "orcid": "0000-0001-5653-5635" }, { "family_name": "Booth", "given_name": "M.", "orcid": "0000-0001-8568-6336" }, { "family_name": "del Burgo", "given_name": "C.", "orcid": "0000-0002-8949-5200" }, { "family_name": "Fehr", "given_name": "A." }, { "family_name": "Mansell", "given_name": "E.", "orcid": "0009-0004-1433-8149" }, { "family_name": "Zawadzki", "given_name": "B.", "orcid": "0000-0001-9319-1296" } ], "abstract": "

Context. CO gas is detected in a significant number (~20) of debris discs (exoKuiper belts), but understanding its origin and evolution remains elusive. Crucial pieces of evidence are its mass and spectro-spatial distribution, which are coupled through optical depth and have only been analysed at low to moderate resolution so far. The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) is the first ALMA large program to target debris discs at high spectro-spatial resolution.

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Aims. We used 12CO and 13CO J=3-2 line data of 18 debris belts observed by ARKS, 5 of which were already known to be gas-bearing, in order to analyse the spectro-spatial distribution of CO and constrain the gas mass in discs that were known to host gas previously, and to search for gas in the remaining 13 discs without previous CO detections.

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Methods. We developed a line-imaging pipeline for ARKS CO data with a high spectro-spatial resolution. Using this tool, we produced line cubes for each of the ARKS targets, with a spatial resolution down to about 70 mas and a spectral resolution of 26 m s−1. We used spectro-spatial shifting and stacking techniques to produce a gallery of maps with the highest possible signal-to-noise ratio (S/N) and with radial and spectral profiles that reveal the distribution and kinematics of gas in five gas-bearing discs at unprecedented detail.

\n

Results. For each of the five gas-bearing discs (HD 9672/49 Ceti, HD 32297, HD 121617, HD 131488, and HD 131835), we constrained the inner radius of the 12CO (rmin ~ 3-68 au), and we found that the radial brightness profile of CO peaked interior to the dust ring, but that CO was also more radially extended than the dust. In a second-generation scenario, this would require significant shielding of CO that would allow it to viscously spread to the observed widths. We present the first radially resolved 12CO/13CO isotopologue flux ratios in five gas-bearing debris discs and found them to be constant with radius for the majority (four out of five) of systems. This indicates that 12CO and 13CO are both optically thick or optically thin throughout the discs. We report CO line fluxes or upper limits for all systems and optical depth dependant masses for the five systems with detected CO. Finally, we analysed the 12CO J=3-2 line luminosities for a range of ARKS debris discs and for debris discs from the literature. We confirm that gas is mostly detected in young systems. However, the high scatter seen in young/high fractional luminosity systems indicates no trend within the systems with detected gas. This could be caused by different system properties and/or evolution pathways.

", "doi": "10.1051/0004-6361/202556605", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A198" }, { "id": "authors:hb67q-wyn33", "collection": "authors", "collection_id": "hb67q-wyn33", "cite_using_url": "https://authors.library.caltech.edu/records/hb67q-wyn33", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). II. The radial structure of debris discs", "author": [ { "family_name": "Han", "given_name": "Yinuo", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Mansell", "given_name": "Elias", "orcid": "0009-0004-1433-8149" }, { "family_name": "Jennings", "given_name": "Jeff" }, { "family_name": "Marino", "given_name": "Sebastian", "orcid": "0000-0002-5352-2924" }, { "family_name": "Hughes", "given_name": "A. Meredith", "orcid": "0000-0002-4803-6200" }, { "family_name": "Zawadzki", "given_name": "Brianna", "orcid": "0000-0001-9319-1296" }, { "family_name": "Fehr", "given_name": "Anna" }, { "family_name": "Kittling", "given_name": "Jamar" }, { "family_name": "Hou", "given_name": "Catherine" }, { "family_name": "Nurmohamed", "given_name": "Aliya", "orcid": "0009-0006-6823-9060" }, { "family_name": "Lee", "given_name": "Junu" }, { "family_name": "Cheruiyot", "given_name": "Allan", "orcid": "0009-0008-5679-1389" }, { "family_name": "Mpofu", "given_name": "Yamani" }, { "family_name": "Booth", "given_name": "Mark", "orcid": "0000-0001-8568-6336" }, { "family_name": "Booth", "given_name": "Richard", "orcid": "0000-0002-0364-937X" }, { "family_name": "Bonduelle", "given_name": "Myriam", "orcid": "0009-0000-7049-8439" }, { "family_name": "Brennan", "given_name": "Aoife", "orcid": "0000-0002-7050-0161" }, { "family_name": "del Burgo", "given_name": "Carlos", "orcid": "0000-0002-8949-5200" }, { "family_name": "Carpenter", "given_name": "John M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Cataldi", "given_name": "Gianni", "orcid": "0000-0002-2700-9676" }, { "family_name": "Chiang", "given_name": "Eugene", "orcid": "0000-0002-6246-2310" }, { "family_name": "Ertel", "given_name": "Steve" }, { "family_name": "Henning", "given_name": "Thomas" }, { "family_name": "Jankovic", "given_name": "Marija R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "\u00c1gnes", "orcid": "0000-0001-7157-6275" }, { "family_name": "Krivov", "given_name": "Alexander V.", "orcid": "0009-0009-4573-2612" }, { "family_name": "Lovell", "given_name": "Joshua B.", "orcid": "0000-0002-4248-5443" }, { "family_name": "Luppe", "given_name": "Patricia", "orcid": "0000-0002-1018-6203" }, { "family_name": "MacGregor", "given_name": "Meredith A.", "orcid": "0000-0001-7891-8143" }, { "family_name": "Mac Manamon", "given_name": "Sorcha", "orcid": "0000-0002-7066-8052" }, { "family_name": "Marshall", "given_name": "Jonathan P.", "orcid": "0000-0001-6208-1801" }, { "family_name": "Matr\u00e0", "given_name": "Luca", "orcid": "0000-0003-4705-3188" }, { "family_name": "Milli", "given_name": "Julien", "orcid": "0000-0001-9325-2511" }, { "family_name": "Mo\u00f3r", "given_name": "Attila", "orcid": "0009-0001-9360-2670" }, { "family_name": "Olofsson", "given_name": "Johan", "orcid": "0000-0003-4475-3605" }, { "family_name": "Pearce", "given_name": "Tim", "orcid": "0000-0001-5653-5635" }, { "family_name": "P\u00e9rez", "given_name": "Sebasti\u00e1n", "orcid": "0000-0003-2953-755X" }, { "family_name": "Sefilian", "given_name": "Antranik A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Weber", "given_name": "Philipp", "orcid": "0000-0002-3354-6654" }, { "family_name": "Wilner", "given_name": "David J.", "orcid": "0000-0003-1526-7587" }, { "family_name": "Wyatt", "given_name": "Mark C.", "orcid": "0000-0001-9064-5598" } ], "abstract": "

Context. Debris discs are populated by belts of planetesimals, whose structure carries dynamical imprints of planets and the formation and evolutionary history of the planetary system. The relatively faint emission of debris discs has previously made it challenging to obtain a large sample of high-resolution ALMA images to characterise their substructures.

\n

Aims. The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) was recently completed to cover the lack of high-resolution observations and to investigate the prevalence of substructures such as radial gaps and rings in a sample of 24 debris discs. This study characterises the radial structure of debris discs in the ARKS programme.

\n

Methods. We modelled all discs with a range of non-parametric and parametric approaches, including those that deconvolve and deproject the image or fit the visibilities directly, in order to identify and quantify the disc substructures.

\n

Results. Across the sample we find that of the 24 discs, 5 host multiple rings, 7 are single rings that display halos or additional low-amplitude rings, and 12 are single rings with at most tentative evidence of additional substructures. The fractional ring widths that we measured are significantly narrower than previously derived values, and they follow a distribution similar to the fractional widths of individual rings resolved in protoplanetary discs. However, there exists a population of rings in debris discs that are significantly wider than those in protoplanetary discs. We also find that discs with steep inner edges consistent with planet sculpting tend to be found at smaller (<100 au) radii, while more radially extended discs tend to have shallower edges more consistent with collisional evolution. An overwhelming majority of discs have radial profiles that are well-described by either a double power law or double-Gaussian parametrisation.

\n

Conclusions. While our findings suggest that it may be possible for some debris discs to inherit their structures directly from pro-toplanetary discs, there exists a sizeable population of broad debris discs that cannot be explained in this way. Assuming that the distribution of millimetre dust reflects the distribution of planetesimals, mechanisms that cause rings in protoplanetary discs to migrate or debris discs to broaden soon after formation may be at play, possibly mediated by planetary migration or scattering.

", "doi": "10.1051/0004-6361/202556450", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A196" }, { "id": "authors:jc475-74a64", "collection": "authors", "collection_id": "jc475-74a64", "cite_using_url": "https://authors.library.caltech.edu/records/jc475-74a64", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). I. Motivation, sample, data reduction, and results overview", "author": [ { "family_name": "Marino", "given_name": "S.", "orcid": "0000-0002-5352-2924" }, { "family_name": "Matr\u00e0", "given_name": "L.", "orcid": "0000-0003-4705-3188" }, { "family_name": "Hughes", "given_name": "A. M.", "orcid": "0000-0002-4803-6200" }, { "family_name": "Ehrhardt", "given_name": "J.", "orcid": "0009-0003-9433-043X" }, { "family_name": "Kennedy", "given_name": "G. M.", "orcid": "0000-0001-6831-7547" }, { "family_name": "del Burgo", "given_name": "C.", "orcid": "0000-0002-8949-5200" }, { "family_name": "Brennan", "given_name": "A.", "orcid": "0000-0002-7050-0161" }, { "family_name": "Han", "given_name": "Y.", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Jankovic", "given_name": "M. R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "Lovell", "given_name": "J. B.", "orcid": "0000-0002-4248-5443" }, { "family_name": "Mac Manamon", "given_name": "S.", "orcid": "0000-0002-7066-8052" }, { "family_name": "Milli", "given_name": "J.", "orcid": "0000-0001-9325-2511" }, { "family_name": "Weber", "given_name": "P.", "orcid": "0000-0002-3354-6654" }, { "family_name": "Zawadzki", "given_name": "B.", "orcid": "0000-0001-9319-1296" }, { "family_name": "Bendahan-West", "given_name": "R.", "orcid": "0009-0000-0303-2145" }, { "family_name": "Fehr", "given_name": "A." }, { "family_name": "Mansell", "given_name": "E.", "orcid": "0009-0004-1433-8149" }, { "family_name": "Olofsson", "given_name": "J.", "orcid": "0000-0003-4475-3605" }, { "family_name": "Pearce", "given_name": "T. D.", "orcid": "0000-0001-5653-5635" }, { "family_name": "Bayo", "given_name": "A.", "orcid": "0000-0001-7868-7031" }, { "family_name": "Matthews", "given_name": "B. C.", "orcid": "0000-0003-3017-9577" }, { "family_name": "L\u00f6hne", "given_name": "T.", "orcid": "0000-0003-2584-5280" }, { "family_name": "Wyatt", "given_name": "M. C.", "orcid": "0000-0001-9064-5598" }, { "family_name": "\u00c1brah\u00e1m", "given_name": "P.", "orcid": "0000-0001-6015-646X" }, { "family_name": "Bonduelle", "given_name": "M.", "orcid": "0009-0000-7049-8439" }, { "family_name": "Booth", "given_name": "M.", "orcid": "0000-0001-8568-6336" }, { "family_name": "Cataldi", "given_name": "G.", "orcid": "0000-0002-2700-9676" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Chiang", "given_name": "E.", "orcid": "0000-0002-6246-2310" }, { "family_name": "Ertel", "given_name": "S." }, { "family_name": "Hales", "given_name": "A. S." }, { "family_name": "Henning", "given_name": "Th." }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "\u00c1.", "orcid": "0000-0001-7157-6275" }, { "family_name": "Krivov", "given_name": "A. V.", "orcid": "0009-0009-4573-2612" }, { "family_name": "Luppe", "given_name": "P.", "orcid": "0000-0002-1018-6203" }, { "family_name": "MacGregor", "given_name": "M. A.", "orcid": "0000-0001-7891-8143" }, { "family_name": "Marshall", "given_name": "J. P.", "orcid": "0000-0001-6208-1801" }, { "family_name": "Mo\u00f3r", "given_name": "A.", "orcid": "0009-0001-9360-2670" }, { "family_name": "P\u00e9rez", "given_name": "S.", "orcid": "0000-0003-2953-755X" }, { "family_name": "Sefilian", "given_name": "A. A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Sepulveda", "given_name": "A. G.", "orcid": "0000-0002-8621-2682" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587" } ], "abstract": "

Context. The outer regions of planetary systems host dusty debris discs analogous to the Kuiper belt (exoKuiper belts), which provide crucial constraints on planet formation and evolution processes. ALMA dust observations have revealed a great diversity in terms of radii, widths, and scale heights. At the same time, ALMA has also shown that some belts contain CO gas, whose origin and implications are still highly uncertain. Most of this progress, however, has been limited by low angular resolution observations that hinder our ability to test existing models and theories.

\n

Aims. High-resolution observations of these belts are crucial for understanding the detailed distribution of solids and for constraining the gas distribution and kinematics.

\n

Methods. We conducted the first ALMA large programme dedicated to debris discs: the ALMA survey to Resolve exoKuiper belt Substructures (ARKS). We selected the 24 most promising belts to best address our main objectives: analysing the detailed radial and vertical structure, and characterising the gas content. The data were reduced and corrected to account for several systematic effects, and then imaged. Using parametric and non-parametric models, we constrained the radial and vertical distribution of dust, as well as the presence of asymmetries. For a subset of six belts with CO gas, we constrained the gas distribution and kinematics. To interpret these observations, we used a wide range of dynamical models.

\n

Results. The first results of ARKS are presented as a series of ten papers. We discovered that up to 33% of our sample exhibits substructures in the form of multiple dusty rings that may have been inherited from their protoplanetary discs. For highly inclined belts, we found that non-Gaussian vertical distributions are common and could be indicative of multiple dynamical populations. Half of the derived scale heights are small enough to be consistent with self-stirring in low-mass belts (Mbelt ≤ MNeptune). We also found that 10 of the 24 belts present asymmetries in the form of density enhancements, eccentricities, or warps. We find that the CO gas is radially broader than the dust, but this could be an effect of optical depth. At least one system shows non-Keplerian kinematics due to strong pressure gradients, which may have triggered a vortex that trapped dust in an arc. Finally, we find evidence that the micron-sized grains may be affected by gas drag in gas-rich systems, pushing the small grains to wider orbits than the large grains.

\n

Conclusions. ARKS has revealed a great diversity of radial and vertical structures in exoKuiper belts that may arise when they are formed in protoplanetary discs or subsequently via interactions with planets and/or gas. We encourage the community to explore the reduced data and data products that we have made public through a dedicated website.

", "doi": "10.1051/0004-6361/202556489", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A195" }, { "id": "authors:jkd45-vv172", "collection": "authors", "collection_id": "jkd45-vv172", "cite_using_url": "https://authors.library.caltech.edu/records/jkd45-vv172", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). X. Interpreting the peculiar dust rings around HD 131835", "author": [ { "family_name": "Jankovic", "given_name": "M. R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "Pawellek", "given_name": "N.", "orcid": "0000-0002-9385-9820" }, { "family_name": "Zander", "given_name": "J." }, { "family_name": "L\u00f6hne", "given_name": "T.", "orcid": "0000-0003-2584-5280" }, { "family_name": "Krivov", "given_name": "A. V.", "orcid": "0009-0009-4573-2612" }, { "family_name": "Olofsson", "given_name": "J.", "orcid": "0000-0003-4475-3605" }, { "family_name": "Brennan", "given_name": "A.", "orcid": "0000-0002-7050-0161" }, { "family_name": "Milli", "given_name": "J.", "orcid": "0000-0001-9325-2511" }, { "family_name": "Bonduelle", "given_name": "M.", "orcid": "0009-0000-7049-8439" }, { "family_name": "Wyatt", "given_name": "M. C.", "orcid": "0000-0001-9064-5598" }, { "family_name": "Sefilian", "given_name": "A. A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Pearce", "given_name": "T. D.", "orcid": "0000-0001-5653-5635" }, { "family_name": "Mac Manamon", "given_name": "S.", "orcid": "0000-0002-7066-8052" }, { "family_name": "Han", "given_name": "Y.", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Marino", "given_name": "S.", "orcid": "0000-0002-5352-2924" }, { "family_name": "Matr\u00e0", "given_name": "L.", "orcid": "0000-0003-4705-3188" }, { "family_name": "Mo\u00f3r", "given_name": "A.", "orcid": "0009-0001-9360-2670" }, { "family_name": "Booth", "given_name": "M.", "orcid": "0000-0001-8568-6336" }, { "family_name": "Chiang", "given_name": "E.", "orcid": "0000-0002-6246-2310" }, { "family_name": "Mansell", "given_name": "E.", "orcid": "0009-0004-1433-8149" }, { "family_name": "Weber", "given_name": "P.", "orcid": "0000-0002-3354-6654" }, { "family_name": "Hughes", "given_name": "A. M.", "orcid": "0000-0002-4803-6200" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587" }, { "family_name": "Luppe", "given_name": "P.", "orcid": "0000-0002-1018-6203" }, { "family_name": "Zawadzki", "given_name": "B.", "orcid": "0000-0001-9319-1296" }, { "family_name": "del Burgo", "given_name": "C.", "orcid": "0000-0002-8949-5200" }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "\u00c1.", "orcid": "0000-0001-7157-6275" }, { "family_name": "P\u00e9rez", "given_name": "S.", "orcid": "0000-0003-2953-755X" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Henning", "given_name": "T." } ], "abstract": "

Context. Dusty discs detected around main-sequence stars are thought to be signs of planetesimal belts in which the dust distribution is shaped by collisional and dynamical processes, including interactions with gas if present. The debris disc around the young A-type star HD 131835 is composed of two dust rings at ∼65 au and ∼100 au, a third unconstrained innermost component, and a gaseous component centred at ∼65 au. New ALMA observations show that the inner of the two dust rings is brighter than the outer one, in contrast with previous observations in scattered light.

\n

Aims. We explore two scenarios that could explain these observations: the two dust rings might represent distinct planetesimal belts with different collisional properties, or only the inner ring might contain planetesimals while the outer ring consists entirely of dust that has migrated outwards due to gas drag.

\n

Methods. To explore the first scenario, we employed a state-of-the-art collisional evolution code. To test the second scenario, we used a simple dynamical model of dust grain evolution in an optically thin gaseous disc. In each case we identified the parameters of the planetesimal and the gaseous disc that best reproduce the observational constraints.

\n

Results. Collisional models of two planetesimal belts cannot fully reproduce the observations by only varying their dynamical excitation, and matching the data through a different material strength requires an extreme difference in dust composition. The gas-driven scenario can reproduce the location of the outer ring and the brightness ratio of the two rings from scattered light observations, but the resulting outer ring is too faint overall in both scattered light and sub-millimetre emission.

\n

Conclusions. The dust rings in HD 131835 could be produced from two planetesimal belts, although how these belts would attain the required extremely different properties needs to be explained. The dust-gas interaction is a plausible alternative explanation and deserves further study using a more comprehensive model.

", "doi": "10.1051/0004-6361/202556637", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A204" }, { "id": "authors:x8yky-sek53", "collection": "authors", "collection_id": "x8yky-sek53", "cite_using_url": "https://authors.library.caltech.edu/records/x8yky-sek53", "type": "article", "title": "The ALMA survey to Resolve exoKuiper belt Substructures (ARKS). III. The vertical structure of debris disks", "author": [ { "family_name": "Zawadzki", "given_name": "B.", "orcid": "0000-0001-9319-1296" }, { "family_name": "Fehr", "given_name": "A." }, { "family_name": "Hughes", "given_name": "A. M.", "orcid": "0000-0002-4803-6200" }, { "family_name": "Mansell", "given_name": "E.", "orcid": "0009-0004-1433-8149" }, { "family_name": "Kittling", "given_name": "J." }, { "family_name": "Han", "given_name": "Y.", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Hou", "given_name": "C." }, { "family_name": "Pan", "given_name": "M." }, { "family_name": "Milli", "given_name": "J.", "orcid": "0000-0001-9325-2511" }, { "family_name": "Olofsson", "given_name": "J.", "orcid": "0000-0003-4475-3605" }, { "family_name": "Pearce", "given_name": "T." }, { "family_name": "Sefilian", "given_name": "A. A.", "orcid": "0000-0003-4623-1165" }, { "family_name": "Nurmohamed", "given_name": "A.", "orcid": "0009-0006-6823-9060" }, { "family_name": "Lee", "given_name": "J." }, { "family_name": "Mpofu", "given_name": "Y." }, { "family_name": "Bonduelle", "given_name": "M.", "orcid": "0009-0000-7049-8439" }, { "family_name": "Booth", "given_name": "M.", "orcid": "0000-0001-8568-6336" }, { "family_name": "Brennan", "given_name": "A.", "orcid": "0000-0002-7050-0161" }, { "family_name": "del Burgo", "given_name": "C.", "orcid": "0000-0002-8949-5200" }, { "family_name": "Carpenter", "given_name": "J. M.", "orcid": "0000-0003-2251-0602" }, { "family_name": "Cataldi", "given_name": "G.", "orcid": "0000-0002-2700-9676" }, { "family_name": "Chiang", "given_name": "E.", "orcid": "0000-0002-6246-2310" }, { "family_name": "Ertel", "given_name": "S." }, { "family_name": "Henning", "given_name": "Th." }, { "family_name": "Jankovic", "given_name": "M. R.", "orcid": "0000-0001-6684-6269" }, { "family_name": "Kennedy", "given_name": "G. M.", "orcid": "0000-0001-6831-7547" }, { "family_name": "K\u00f3sp\u00e1l", "given_name": "\u00c1.", "orcid": "0000-0001-7157-6275" }, { "family_name": "Krivov", "given_name": "A. V.", "orcid": "0009-0009-4573-2612" }, { "family_name": "Lovell", "given_name": "J. B.", "orcid": "0000-0002-4248-5443" }, { "family_name": "Luppe", "given_name": "P.", "orcid": "0000-0002-1018-6203" }, { "family_name": "MacGregor", "given_name": "M. A.", "orcid": "0000-0001-7891-8143" }, { "family_name": "Mac Manamon", "given_name": "S.", "orcid": "0000-0002-7066-8052" }, { "family_name": "Marino", "given_name": "S.", "orcid": "0000-0002-5352-2924" }, { "family_name": "Marshall", "given_name": "J. P.", "orcid": "0000-0001-6208-1801" }, { "family_name": "Matr\u00e0", "given_name": "L." }, { "family_name": "Mo\u00f3r", "given_name": "A.", "orcid": "0009-0001-9360-2670" }, { "family_name": "P\u00e9rez", "given_name": "S.", "orcid": "0000-0003-2953-755X" }, { "family_name": "Weber", "given_name": "P.", "orcid": "0000-0002-3354-6654" }, { "family_name": "Wilner", "given_name": "D. J.", "orcid": "0000-0003-1526-7587" }, { "family_name": "Wyatt", "given_name": "M. C.", "orcid": "0000-0001-9064-5598" } ], "abstract": "

Context. Debris disks – collisionally sustained belts of dust and sometimes gas around main sequence stars – are remnants of planet formation processes and are found in systems \u227310 Myr old. Millimeter-wavelength observations are particularly important, as the grains probed by these observations are not strongly affected by radiation pressure and stellar winds, allowing them to probe the dynamics of large bodies producing dust. The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) is analyzing high-resolution observations of 24 debris disks to enable the characterization of debris disk substructures across a large sample for the first time.

\n

Aims. For the most highly inclined disks, it is possible to recover the vertical structure of the disk. We aim to model and analyze the most highly inclined systems in the ARKS sample in order to uniformly extract the vertical dust distributions for a sample of well-resolved debris disks.

\n

Methods. We employed both parametric and nonparametric methods to constrain the vertical dust distributions for the most highly inclined ARKS targets.

\n

Results. We find a broad range of aspect ratios, revealing a wide diversity in vertical structure, with a range of best-fit parametric values of 0.0026 ≤ hHWHM ≤ 0.193 and a median best-fit value of hHWHM = 0.021. The results obtained by nonparametric modeling are generally consistent with the parametric modeling results. We find that five of the 13 disks are consistent with having total disk masses less than that of Neptune (17 M⊕), assuming stirring by internal processes (self-stirring and collisional and frictional damping). Furthermore, most systems show a significant preference for a Lorentzian vertical profile rather than a Gaussian.

", "doi": "10.1051/0004-6361/202556505", "issn": "0004-6361", "publisher": "EDP Sciences", "publication": "Astronomy & Astrophysics", "publication_date": "2026-01", "volume": "705", "pages": "A197" }, { "id": "authors:52nsj-em211", "collection": "authors", "collection_id": "52nsj-em211", "cite_using_url": "https://authors.library.caltech.edu/records/52nsj-em211", "type": "article", "title": "The Formation and Evolution of Dust in the Colliding-wind Binary Apep Revealed by JWST", "author": [ { "family_name": "Han", "given_name": "Yinuo", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "White", "given_name": "Ryan M. T.", "orcid": "0009-0006-7054-0880" }, { "family_name": "Callingham", "given_name": "Joseph R.", "orcid": "0000-0002-7167-1819" }, { "family_name": "Lau", "given_name": "Ryan M.", "orcid": "0000-0003-0778-0321", "clpid": "Lau-Ryan-M" }, { "family_name": "Pope", "given_name": "Benjamin J. S.", "orcid": "0000-0003-2595-9114" }, { "family_name": "Richardson", "given_name": "Noel D.", "orcid": "0000-0002-2806-9339" }, { "family_name": "Tuthill", "given_name": "Peter G.", "orcid": "0000-0001-7026-6291" } ], "abstract": "

Carbon-rich Wolf–Rayet (W-R) stars are significant contributors of carbonaceous dust to the galactic environment; however, the mechanisms and conditions for formation and subsequent evolution of dust around these stars remain open questions. Here we present JWST observations of the W-R+W-R colliding-wind binary Apep, which reveal an intricate series of nested concentric dust shells that are abundant in detailed substructure. The striking regularity in these substructures between successive shells suggests an exactly repeating formation mechanism combined with a highly stable outflow that maintains a consistent morphology even after reaching 0.6 pc (assuming a distance of 2.4 kpc) into the interstellar medium. The concentric dust shells show subtle deviations from spherical outflow, which could reflect orbital modulation along the eccentric binary orbit or nonsphericity in the stellar wind. Tracking the evolution of dust across the multitiered structure, we measure the dust temperature evolution that can broadly be described assuming an amorphous carbon composition in radiative thermal equilibrium with the central stars. The temperature profile and orbital period place new distance constraints that support Apep being at a greater distance than previously estimated, reducing the line-of-sight and sky-plane wind speed discrepancy previously thought to characterize the system.

", "doi": "10.3847/1538-4357/ae12e5", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2025-11-20", "series_number": "1", "volume": "994", "issue": "1", "pages": "122" }, { "id": "authors:wpc8c-am924", "collection": "authors", "collection_id": "wpc8c-am924", "cite_using_url": "https://authors.library.caltech.edu/records/wpc8c-am924", "type": "article", "title": "Revealing the Accelerating Wind in the Inner Region of Colliding-wind Binary WR 112", "author": [ { "family_name": "Monnier", "given_name": "John D.", "orcid": "0000-0002-3380-3307" }, { "family_name": "Han", "given_name": "Yinuo", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Corcoran", "given_name": "Michael F.", "orcid": "0000-0002-7762-3172" }, { "family_name": "Bloot", "given_name": "Sanne", "orcid": "0000-0002-3601-6165" }, { "family_name": "Callingham", "given_name": "Joseph R.", "orcid": "0000-0002-7167-1819" }, { "family_name": "Danchi", "given_name": "William" }, { "family_name": "Edwards", "given_name": "Philip G.", "orcid": "0000-0002-8186-4753" }, { "family_name": "Greenhill", "given_name": "Lincoln" }, { "family_name": "Hamaguchi", "given_name": "Kenji", "orcid": "0000-0001-7515-2779" }, { "family_name": "Hankins", "given_name": "Matthew J.", "orcid": "0000-0001-9315-8437" }, { "family_name": "Lau", "given_name": "Ryan" }, { "family_name": "Miller", "given_name": "Jon M.", "orcid": "0000-0003-2869-7682" }, { "family_name": "Moffat", "given_name": "Anthony F. J.", "orcid": "0000-0002-4333-9755" }, { "family_name": "Ruane", "given_name": "Garreth", "orcid": "0000-0003-4769-1665", "clpid": "Ruane-Garreth" }, { "family_name": "Russell", "given_name": "Christopher M. P.", "orcid": "0000-0002-9213-0763" }, { "family_name": "Soulain", "given_name": "Anthony" }, { "family_name": "Tinyanont", "given_name": "Samaporn", "orcid": "0000-0002-1481-4676" }, { "family_name": "Tuthill", "given_name": "Peter", "orcid": "0000-0001-7026-6291" }, { "family_name": "Wang", "given_name": "Jason J.", "orcid": "0000-0003-0774-6502", "clpid": "Wang-Jason-J" }, { "family_name": "Williams", "given_name": "Peredur M.", "orcid": "0000-0002-8092-980X" } ], "abstract": "

Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty “pinwheel” spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 yr of Very Large Array/Australia Telescope Compact Array radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf–Rayet wind self-absorption and near-transparent O-star wind foreground each 20 yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger nonthermal contribution around the radio intensity maximum, which indeed was observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared (IR) geometry and radio light curve. Instead, we require an accelerating postshock flow that climbs from near-stationary to ∼1350 km s−1 in about one orbital cycle, naturally matching the IR spiral from 5″ down to within 0.\"1, while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, nonthermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions.

", "doi": "10.3847/1538-3881/adfa03", "issn": "0004-6256", "publisher": "American Astronomical Society", "publication": "Astronomical Journal", "publication_date": "2025-10", "series_number": "4", "volume": "170", "issue": "4", "pages": "218" }, { "id": "authors:a0ch6-g2p93", "collection": "authors", "collection_id": "a0ch6-g2p93", "cite_using_url": "https://authors.library.caltech.edu/records/a0ch6-g2p93", "type": "article", "title": "Carbon-rich Dust Injected into the Interstellar Medium by Galactic WC Binaries Survives for Hundreds of Years", "author": [ { "family_name": "Richardson", "given_name": "Noel D.", "orcid": "0000-0002-2806-9339" }, { "family_name": "Henson", "given_name": "Micaela", "orcid": "0009-0003-4158-4508" }, { "family_name": "Lieb", "given_name": "Emma P.", "orcid": "0000-0002-4660-7452" }, { "family_name": "Kehl", "given_name": "Corey" }, { "family_name": "Lau", "given_name": "Ryan M.", "orcid": "0000-0003-0778-0321" }, { "family_name": "Williams", "given_name": "Peredur M.", "orcid": "0000-0002-8092-980X" }, { "family_name": "Corcoran", "given_name": "Michael F.", "orcid": "0000-0002-7762-3172" }, { "family_name": "Callingham", "given_name": "J. R.", "orcid": "0000-0002-7167-1819" }, { "family_name": "Chen\u00e9", "given_name": "Andr\u00e9-Nicolas", "orcid": "0000-0002-1115-6559" }, { "family_name": "Gull", "given_name": "Theodore R.", "orcid": "0000-0002-6851-5380" }, { "family_name": "Hamaguchi", "given_name": "Kenji", "orcid": "0000-0001-7515-2779" }, { "family_name": "Han", "given_name": "Yinuo", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" }, { "family_name": "Hankins", "given_name": "Matthew J.", "orcid": "0000-0001-9315-8437" }, { "family_name": "Hill", "given_name": "Grant M.", "orcid": "0000-0002-7648-9119" }, { "family_name": "Hoffman", "given_name": "Jennifer L.", "orcid": "0000-0003-1495-2275" }, { "family_name": "Mackey", "given_name": "Jonathan", "orcid": "0000-0002-5449-6131" }, { "family_name": "Moffat", "given_name": "Anthony F. J.", "orcid": "0000-0002-4333-9755" }, { "family_name": "Pope", "given_name": "Benjamin J. S.", "orcid": "0000-0003-2595-9114" }, { "family_name": "Pradhan", "given_name": "Pragati", "orcid": "0000-0002-1131-3059" }, { "family_name": "Russell", "given_name": "Christopher M. P.", "orcid": "0000-0002-9213-0763" }, { "family_name": "Sander", "given_name": "Andreas A. C.", "orcid": "0000-0002-2090-9751" }, { "family_name": "St-Louis", "given_name": "Nicole", "orcid": "0000-0003-3890-3400" }, { "family_name": "Stevens", "given_name": "Ian R.", "orcid": "0000-0001-7673-4340" }, { "family_name": "Tuthill", "given_name": "Peter", "orcid": "0000-0001-7026-6291" }, { "family_name": "Weigelt", "given_name": "Gerd", "orcid": "0000-0001-9754-2233" }, { "family_name": "White", "given_name": "Ryan M. T.", "orcid": "0009-0006-7054-0880" } ], "abstract": "
\n

Some carbon-rich Wolf–Rayet (WC) stars show an infrared excess from dust emission (WCd stars). Dust forms in the collision of the WC wind with a companion star’s wind. As this dust is carried toward the interstellar medium (ISM) at close to the WCd wind speed and the binary continues through its orbit, a spiral structure forms around the system. The shape depends on the orbital eccentricity and period, as well as stellar parameters like mass-loss rates and terminal wind speeds. Imaging of the WCd binary WR 140 with JWST/MIRI revealed 17 concentric dust shells surrounding the binary. We present new JWST imaging of four additional WCd systems (WR 48a, WR 112, WR 125, and WR 137) that were imaged in 2024. In this analysis, we show that the dust is long-lived, detected with an age of at least 130 yr, but more than 300 yr in some systems. Longer-duration measurements are limited by sensitivity. Regular spacing of dust features confirms the periodic nature of dust formation, consistent with a connection to binary motion. We use these images to estimate the proper motion of the dust, finding the dust to propagate out to the ISM with motion comparable to the wind speed of the WC stars. In addition to these results, we observe unusual structures around WR 48a, which could represent dusty clumps shaped by photoevaporation and wind ablation like young proplyd objects. These results demonstrate that WC dust is indeed long-lived and should be accounted for in galactic dust budgets.

\n
", "doi": "10.3847/1538-4357/addf30", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2025-07-10", "series_number": "2", "volume": "987", "issue": "2", "pages": "160" }, { "id": "authors:spyjh-2hm25", "collection": "authors", "collection_id": "spyjh-2hm25", "cite_using_url": "https://authors.library.caltech.edu/records/spyjh-2hm25", "type": "article", "title": "A PR drag origin for the Fomalhaut disc's pervasive inner dust: constraints on collisional strengths, icy composition, and embedded planets", "author": [ { "family_name": "Sommer", "given_name": "Max", "orcid": "0000-0003-4761-5785" }, { "family_name": "Wyatt", "given_name": "Mark", "orcid": "0000-0001-9064-5598" }, { "family_name": "Han", "given_name": "Yinuo", "orcid": "0000-0002-2106-0403", "clpid": "Han-Yinuo" } ], "abstract": "

Recent JWST observations of the Fomalhaut debris disc have revealed a significant abundance of dust interior to the outer planetesimal belt, raising questions about its origin and maintenance. In this study, we apply an analytical model to the Fomalhaut system, which simulates the dust distribution interior to a planetesimal belt, as collisional fragments across a range of sizes are dragged inward under Poynting–Robertson (PR) drag. We generate spectral energy distributions and synthetic JWST/MIRI images of the model discs, and perform an extensive grid search for particle parameters – pertaining to composition and collisional strength – that best match the observations. We find that a sound fit can be found for particle properties that involve a substantial water ice component, around 50–80 per cent by total volume, and a catastrophic disruption threshold, Q*D\u2060, at a particle size of D≈30 µm of (2–4)\u2060 x 10\u2076 erg g\u207b¹. Based on the expected dynamical depletion of migrating dust by an intervening planet, we discount planets with masses  > 1 M_(Saturn) beyond ~50 au in the extended disc, though a planet shepherding the inner edge of the outer belt of up to ~2 M_(Saturn) is reconcilable with the PR-drag-maintained disc scenario, contingent upon higher collisional strengths. These results indicate that PR drag transport from the outer belt alone can account for the high interior dust contents seen in the Fomalhaut system, which may thus constitute a common phenomenon in other belt-bearing systems. This establishes a framework for interpreting mid-planetary system dust around other stars, with our results for Fomalhaut providing a valuable calibration of the models.

", "doi": "10.1093/mnras/staf494", "issn": "0035-8711", "publisher": "Royal Astronomical Society", "publication": "Monthly Notices of the Royal Astronomical Society", "publication_date": "2025-05", "series_number": "1", "volume": "539", "issue": "1", "pages": "439-456" }, { "id": "authors:5kqmz-hbb65", "collection": "authors", "collection_id": "5kqmz-hbb65", "cite_using_url": "https://authors.library.caltech.edu/records/5kqmz-hbb65", "type": "article", "title": "Dynamic Imprints of Colliding-wind Dust Formation from WR 140", "author": [ { "family_name": "Lieb", "given_name": "Emma P.", "orcid": "0000-0002-4660-7452" }, { "family_name": "Lau", "given_name": "Ryan M.", "orcid": "0000-0003-0778-0321" }, { "family_name": "Hoffman", "given_name": "Jennifer L.", "orcid": "0000-0003-1495-2275" }, { "family_name": "Corcoran", "given_name": "Michael F.", "orcid": "0000-0002-7762-3172" }, { "family_name": "Garcia Marin", "given_name": "Macarena", "orcid": "0000-0003-4801-0489" }, { "family_name": "Gull", "given_name": "Theodore R.", "orcid": "0000-0002-6851-5380" }, { "family_name": "Hamaguchi", "given_name": "Kenji", "orcid": "0000-0001-7515-2779" }, { "family_name": "Han", "given_name": "Yinuo", "clpid": "Han-Yinuo" }, { "family_name": "Hankins", "given_name": "Matthew J.", "orcid": "0000-0001-9315-8437" }, { "family_name": "Jones", "given_name": "Olivia C.", "orcid": "0000-0003-4870-5547" }, { "family_name": "Madura", "given_name": "Thomas I." }, { "family_name": "Marchenko", "given_name": "Sergey V." }, { "family_name": "Matsuhara", "given_name": "Hideo" }, { "family_name": "Millour", "given_name": "Florentin" }, { "family_name": "Moffat", "given_name": "Anthony F. J.", "orcid": "0000-0002-4333-9755" }, { "family_name": "Morris", "given_name": "Mark R.", "orcid": "0000-0002-6753-2066" }, { "family_name": "Morris", "given_name": "Patrick W.", "clpid": "Morris-Patrick-W" }, { "family_name": "Onaka", "given_name": "Takashi", "orcid": "0000-0002-8234-6747" }, { "family_name": "Perrin", "given_name": "Marshall D.", "orcid": "0000-0002-3191-8151" }, { "family_name": "Rest", "given_name": "Armin", "orcid": "0000-0002-4410-5387" }, { "family_name": "Richardson", "given_name": "Noel", "orcid": "0000-0002-2806-9339" }, { "family_name": "Russell", "given_name": "Christopher M. P.", "orcid": "0000-0002-9213-0763" }, { "family_name": "Sanchez-Bermudez", "given_name": "Joel", "orcid": "0000-0002-9723-0421" }, { "family_name": "Soulain", "given_name": "Anthony", "orcid": "0000-0001-7661-5130" }, { "family_name": "Tuthill", "given_name": "Peter", "orcid": "0000-0001-7026-6291" }, { "family_name": "Weigelt", "given_name": "Gerd" }, { "family_name": "Williams", "given_name": "Peredur M.", "orcid": "0000-0002-8092-980X" } ], "abstract": "
\n

Carbon-rich Wolf–Rayet (WR) binaries are a prominent source of carbonaceous dust that contribute to the dust budget of galaxies. The \"textbook\" example of an episodic dust-producing WR binary, WR 140 (HD 193793), provides us with an ideal laboratory for investigating the dust physics and kinematics in an extreme environment. This study is among the first to utilize two separate JWST observations, from Cycle 1 ERS (2022 July) and Cycle 2 (2023 September), to measure WR 140's dust kinematics and confirm its morphology. To measure the proper motions and projected velocities of the dust shells, we performed a novel point-spread function (PSF) subtraction to reduce the effects of the bright diffraction spikes and carefully aligned the Cycle 2 to the Cycle 1 images. At 7.7 μm, through the bright feature common to 16 dust shells (C1), we find an average dust shell proper motion of 390  ±  29 mas yr−1, which equates to a projected velocity of 2714  ±  188 km s−1 at a distance of 1.64 kpc. Our measured speeds are constant across all visible shells and consistent with previously reported dust expansion velocities. Our observations not only prove that these dusty shells are astrophysical (i.e., not associated with any PSF artifact) and originate from WR 140, but also confirm the \"clumpy\" morphology of the dust shells, in which identifiable substructures within certain shells persist for at least 14 months from one cycle to the next. These results support the hypothesis that clumping in the wind collision region is required for dust production in WR binaries.

\n
", "doi": "10.3847/2041-8213/ad9aa9", "issn": "2041-8205", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal Letters", "publication_date": "2025-01-20", "series_number": "1", "volume": "979", "issue": "1", "pages": "L3" }, { "id": "authors:pgd7r-sfm79", "collection": "authors", "collection_id": "pgd7r-sfm79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200921-113043905", "type": "article", "title": "Resolving Decades of Periodic Spirals from the Wolf\u2013Rayet Dust Factory WR 112", "author": [ { "family_name": "Lau", "given_name": "Ryan M.", "clpid": "Lau-Ryan-M" }, { "family_name": "Hankins", "given_name": "Matthew J.", "orcid": "0000-0001-9315-8437", "clpid": "Hankins-M-J" }, { "family_name": "Han", "given_name": "Yinuo", "clpid": "Han-Yinuo" }, { "family_name": "Endo", "given_name": "Izumi", "clpid": "Endo-Izumi" }, { "family_name": "Moffat", "given_name": "Anthony F. J.", "clpid": "Moffat-A-F-J" }, { "family_name": "Ressler", "given_name": "Michael E.", "orcid": "0000-0001-5644-8830", "clpid": "Ressler-M-E" }, { "family_name": "Sakon", "given_name": "Itsuki", "orcid": "0000-0001-7641-5497", "clpid": "Sakon-Itsuki" }, { "family_name": "Sanchez-Bermudez", "given_name": "Joel", "orcid": "0000-0002-9723-0421", "clpid": "Sanchez-Bermudez-J" }, { "family_name": "Soulain", "given_name": "Anthony", "clpid": "Soulain-Anthony" }, { "family_name": "Stevens", "given_name": "Ian R.", "orcid": "0000-0001-7673-4340", "clpid": "Stevens-Ian-R" }, { "family_name": "Tuthill", "given_name": "Peter G.", "clpid": "Tuthill-P-G" }, { "family_name": "Williams", "given_name": "Peredur M.", "orcid": "0000-0002-8092-980X", "clpid": "Williams-P-M" } ], "abstract": "WR 112 is a dust-forming carbon-rich Wolf\u2013Rayet (WC) binary with a dusty circumstellar nebula that exhibits a complex asymmetric morphology, which traces the orbital motion and dust formation in the colliding winds of the central binary. Unraveling the complicated circumstellar dust emission around WR 112 therefore provides an opportunity to understand the dust formation process in colliding-wind WC binaries. In this work, we present a multi-epoch analysis of the circumstellar dust around WR 112 using seven high spatial resolution (FWHM ~ 0farcs3\u20130farcs4) N-band (\u03bb ~ 12 \u03bcm) imaging observations spanning almost 20 yr and that includes images obtained from Subaru/COMICS in 2019 October. In contrast to previous interpretations of a face-on spiral morphology, we observe clear evidence of proper motion of the circumstellar dust around WR 112 consistent with a nearly edge-on spiral with a \u03b8_s = 55\u00b0 half-opening angle and a ~20 yr period. The revised near edge-on geometry of WR 112 reconciles previous observations of highly variable nonthermal radio emission that was inconsistent with a face-on geometry. We estimate a revised distance to WR 112 of d = 3.39_(-0.84)^(+0.89) kpc based on the observed dust expansion rate and a spectroscopically derived WC terminal wind velocity of v_\u221e = 1230 \u00b1 260 km s\u207b\u00b9. With the newly derived WR 112 parameters, we fit optically thin dust spectral energy distribution models and determine a dust production rate of \u1e40_d = 2.7_(-1.3)^(+1.0) x 10\u207b\u2076 M_\u2299 yr\u207b\u00b9, which demonstrates that WR 112 is one of the most prolific dust-making WC systems known.", "doi": "10.3847/1538-4357/abaab8", "issn": "1538-4357", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2020-09-10", "series_number": "2", "volume": "900", "issue": "2", "pages": "Art. No. 190" } ]