exoALMA IV: Substructures, Asymmetries, and the Faint Outer Disk in Continuum Emission
Abstract
The exoALMA Large Program targeted a sample of 15 disks to study gas dynamics within these systems, and these observations simultaneously produced continuum data at 0.9 mm (331.6 GHz) with exceptional surface brightness sensitivity at high angular resolution. To provide a robust characterization of the observed substructures, we performed a visibility space analysis of the continuum emission from the exoALMA data, characterizing axisymmetric substructures and nonaxisymmetric residuals obtained by subtracting an axisymmetric model from the observed data. We defined a nonaxisymmetry index and found that the most asymmetric disks predominantly show an inner cavity and consistently present higher values of mass accretion rate and near-infrared excess. This suggests a connection between outer disk dust substructures and inner disk properties. The depth of the data allowed us to describe the azimuthally averaged continuum emission in the outer disk, revealing that larger disks (both in dust and gas) in our sample tend to be gradually tapered compared to the sharper outer edge of more compact sources. Additionally, the data quality revealed peculiar features in various sources, such as shadows, inner disk offsets, tentative external substructures, and a possible dust cavity wall.
Cite
@article{arxiv.2504.18725,
title = {exoALMA IV: Substructures, Asymmetries, and the Faint Outer Disk in Continuum Emission},
author = {Pietro Curone and Stefano Facchini and Sean M. Andrews and Leonardo Testi and Myriam Benisty and Ian Czekala and Jane Huang and John D. Ilee and Andrea Isella and Giuseppe Lodato and Ryan A. Loomis and Jochen Stadler and Andrew J. Winter and Jaehan Bae and Marcelo Barraza-Alfaro and Gianni Cataldi and Nicolás Cuello and Daniele Fasano and Mario Flock and Misato Fukagawa and Maria Galloway-Sprietsma and Himanshi Garg and Cassandra Hall and Andrés F. Izquierdo and Kazuhiro Kanagawa and Geoffroy Lesur and Cristiano Longarini and Francois Menard and Ryuta Orihara and Christophe Pinte and Daniel J. Price and Giovanni Rosotti and Richard Teague and Gaylor Wafflard-Fernandez and David J. Wilner and Lisa Wölfer and Hsi-Wei Yen and Tomohiro C. Yoshida and Brianna Zawadzki},
journal= {arXiv preprint arXiv:2504.18725},
year = {2025}
}
Comments
This paper is part of the exoALMA Focus Issue of The Astrophysical Journal Letters