REsolved ALMA and SMA Observations of Nearby Stars (REASONS)

A population of 74 resolved planetesimal belts at millimetre wavelengths

¹ School of Physics, Trinity College Dublin, the University of Dublin, College Green, Dublin 2, Ireland
² Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
³ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
⁴ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
⁵ UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
⁶ Astrophysikalisches Institut und Universitätssternwarte, Friedrich–Schiller–Universität Jena, Schillergäßchen 2–3, 07745 Jena, Germany
⁷ Institute for Astronomy, University of Hawaii, Honolulu, HI 96822, USA
⁸ Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Dr., Middletown, CT 06459, USA
⁹ Instituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna, 38200, Tenerife, Spain
¹⁰ Departamento de Astrofísica, Universidad de la Laguna, La Laguna, 38200, Tenerife, Spain
¹¹ Joint ALMA Observatory, Avenida Alonso de Córdova 3107, Vitacura, Santiago, Chile
¹² Department of Astronomy and Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721-0065, USA
¹³ Large Binocular Telescope Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721-0065, USA
¹⁴ LESIA, Observatoire de Paris, Université PSL, CNRS, Université Paris Cité, Sorbonne Université, 5 place Jules Janssen, 92195 Meudon, France
¹⁵ LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC, 75014 Paris, France
¹⁶ Academia Sinica Institute of Astronomy and Astrophysics, 11F of AS/NTU Astronomy-Mathematics Building, No.1, Section 4, Roosevelt Road, Taipei 106216, Taiwan
¹⁷ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹⁸ Institut für Astrophysik, Universität Wien, Türkenschanzstraße 17, 1180 Vienna, Austria
¹⁹ Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly-Thege Miklós út 15–17, 1121 Budapest, Hungary
²⁰ The University of Texas School of Law. 727 E. Dean Keeton Street Austin, TX 78705, USA
²¹ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
²² Herzberg Astronomy & Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E9, Canada
²³ Department of Physics & Astronomy, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8P 5C2, Canada
²⁴ Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA

^★ Corresponding author; lmatra@tcd.ie

Received: 5 July 2024
Accepted: 9 October 2024

Abstract

Context. Planetesimal belts are ubiquitous around nearby stars, and their spatial properties hold crucial information for planetesimal and planet formation models.

Aims. We present resolved dust observations of 74 planetary systems as part of the REsolved ALMA and SMA Observations of Nearby Stars (REASONS) survey and archival reanalysis.

Methods. We uniformly modelled interferometric visibilities for the entire sample to obtain the basic spatial properties of each belt, and combined these with constraints from multi-wavelength photometry.

Results. We report key findings from a first exploration of this legacy dataset: (1) Belt dust masses are depleted over time in a radially dependent way, with dust being depleted faster in smaller belts, as predicted by collisional evolution. (2) Most belts are broad discs rather than narrow rings, with much broader fractional widths than rings in protoplanetary discs. We link broad belts to either unresolved substructure or broad planetesimal discs produced if protoplanetary rings migrate. (3) The vertical aspect ratios (h = H/R) of 24 belts indicate orbital inclinations of ~1–20º, implying relative particle velocities of ~0.1–4 km/s, and no clear evolution of heights with system age. This could be explained by early stirring within the belt by large bodies (with sizes of at least ~140 km to the size of the Moon), by inheritance of inclinations from the protoplanetary disc stage, or by a diversity in evolutionary pathways and gravitational stirring mechanisms. We release the REASONS legacy multidimensional sample of millimetre-resolved belts to the community as a valuable tool for follow-up multi-wavelength observations and population modelling studies.