The ALMA survey to Resolve exoKuiper belt Substructures (ARKS)

III. The vertical structure of debris disks

¹ Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Dr., Middletown, CT 06459, USA
² Center for Astrophysics | Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138, USA
³ Kavli Institute for Particle Astrophysics and Cosmology, 382 Via Pueblo Mall Stanford, CA 94305-4060, USA
⁴ Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA
⁵ Smithsonian Astrophysical Observatory, 60 Garden St, Cambridge, MA 02138, USA
⁶ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁷ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
⁸ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
⁹ Department of Astronomy and Steward Observatory, The University of Arizona, 933 North Cherry Ave, Tucson, AZ 85721, USA
¹⁰ UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
¹¹ School of Physics, Trinity College Dublin, the University of Dublin, College Green, Dublin 2, Ireland
¹² Instituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna, 38200 Tenerife, Spain
¹³ Departamento de Astrofísica, Universidad de La Laguna, La Laguna, 38200 Tenerife, Spain
¹⁴ Joint ALMA Observatory, Avenida Alonso de Córdova 3107, Vitacura 7630355, Santiago, Chile
¹⁵ National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan
¹⁶ Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
¹⁷ Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720-3411, USA
¹⁸ Large Binocular Telescope Observatory, The University of Arizona, 933 North Cherry Ave, Tucson, AZ 85721, USA
¹⁹ Max-Planck-Insitut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
²⁰ Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
²¹ Malaghan Institute of Medical Research, Gate 7, Victoria University, Kelburn Parade, Wellington, New Zealand
²² Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, MTA Centre of Excellence, Konkoly-Thege Miklós út 15–17, 1121 Budapest, Hungary
²³ Institute of Physics and Astronomy, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
²⁴ Astrophysikalisches Institut und Universitätssternwarte, Friedrich- Schiller-Universität Jena, Schillergäßchen 2-3, 07745 Jena, Germany
²⁵ Department of Physics and Astronomy, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
²⁶ Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
²⁷ Academia Sinica Institute of Astronomy and Astrophysics, 11F of AS/NTU Astronomy-Mathematics Building, No.1, Sect. 4, Roosevelt Rd, Taipei 106319, Taiwan
²⁸ Departamento de Física, Universidad de Santiago de Chile, Av. Víctor Jara 3493, Santiago, Chile
²⁹ Millennium Nucleus on Young Exoplanets and their Moons (YEMS), Chile
³⁰ Center for Interdisciplinary Research in Astrophysics Space Exploration (CIRAS), Universidad de Santiago, Chile
³¹ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK

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Received: 18 July 2025
Accepted: 12 September 2025

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 ≳10 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.

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.

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

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 ≤ h_HWHM ≤ 0.193 and a median best-fit value of h_HWHM = 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.