exoALMA. XII. Weighing and Sizing exoALMA Disks with Rotation Curve Modelling

Year: 2025

Type: article

Abstract: The exoALMA large program offers a unique opportunity to investigate the fundamental properties of protoplanetary disks, such as their masses and sizes, providing important insights into the mechanism responsible for the transport of angular momentum. In this work, we model the rotation curves of CO isotopologues 12CO and 13CO of 10 sources within the exoALMA sample, and we constrain the stellar mass, the disk mass, and the density scale radius through precise characterization of the pressure gradient and disk self-gravity. We obtain dynamical disk masses for our sample by measuring the self-gravitating contribution to the gravitational potential. We are able to parametrically describe their surface density, and all of them appear gravitationally stable. By combining dynamical disk masses with dust continuum emission data, we determine an averaged gas-to-dust ratio of approximately 400, not statistically consistent with the standard value of 100, assuming optically thin dust emission. In addition, the measurement of the dynamical scale radius allows for direct comparison with flux-based radii of gas and dust. This comparison suggests that substructures may influence the size of the dust disk and that CO depletion might reconcile our measurements with thermochemical models. Finally, with the stellar mass, disk mass, scale radius, and accretion rate, and assuming self-similar evolution of the surface density, we constrain the effective α S for these systems. We find a broad range of α S values ranging between 10−5 and 10−2.

Source: The Astrophysical Journal Letters

DOI: 10.3847/2041-8213/adc431

Institutions: University of Milan, University of Cambridge, Center for Astrophysics Harvard & Smithsonian, Centre National de la Recherche Scientifique, Université Côte d'Azur, Max Planck Institute for Astronomy, Lagrange Laboratory, Observatoire de la Côte d’Azur, Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes, Leiden University, European Southern Observatory, University of Florida, Leiden Observatory, University of Chile, Massachusetts Institute of Technology, National Astronomical Observatory of Japan, University of St Andrews, Monash University, University of Georgia, Columbia University, University of Leeds, Rice University, Ibaraki University, National Radio Astronomy Observatory, University of Bologna, Institute of Astronomy and Astrophysics, Academia Sinica, Academia Sinica, The Graduate University for Advanced Studies, SOKENDAI, Wesleyan University

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,400

Funders: National Science Foundation, National Aeronautics and Space Administration, Space Telescope Science Institute, National Radio Astronomy Observatory, University of Leeds, European Commission, Fondazione Cariplo, Nuclear Safety and Security Commission, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, Agencia Nacional de Investigación y Desarrollo, HORIZON EUROPE Framework Programme, Science and Technology Facilities Council, Australian Research Council, Japan Society for the Promotion of Science, National Institutes of Natural Sciences

OpenAlex ID: W4409885639