The MATISSE view of the inner region of the RY Tau protoplanetary disk^★

¹ Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24118 Kiel, Germany
² Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, HUN-REN, Konkoly Thege Miklós út 15–17., 1121 Budapest, Hungary
³ Laboratoire Lagrange, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Boulevard de l’Observatoire, CS 34229, 06304 Nice Cedex 4, France
⁴ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁵ NOVA Optical IR Instrumentation Group at ASTRON, The Netherlands
⁶ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁷ NASA Goddard Space Flight Center, Astrophysics Division, Greenbelt, MD 20771, USA
⁸ Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1090 GE Amsterdam, The Netherlands
⁹ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹⁰ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
¹¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
¹² Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721, USA
¹³ Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, Cologne 50937, Germany
¹⁴ School of Physics & Astronomy, University of Southampton, University Road, Southampton SO17 1BJ, UK
¹⁵ European Southern Observatory, Alonso de Córdova, 3107 Vitacura, Santiago, Chile
¹⁶ AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France

^★★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 28 May 2025
Accepted: 27 October 2025

Abstract

Context. The physical conditions and processes taking place in the innermost regions of protoplanetary disks are essential for planet formation and general disk evolution. In this context, we study the T-Tauri type young stellar object RY Tau, which exhibits a dust-depleted inner cavity characteristic of a transition disk.

Aims. The goal of this study is to analyze spectrally resolved interferometric observations in the L, M, and N bands of the RY Tau protoplanetary disk obtained with MATISSE. We aim to provide constraints on the spatial distribution and mineralogy of dust in the inner few astronomical units by producing synthetic observations fitting the interferometric observables.

Methods. We employed a 2D temperature gradient disk model to estimate the orientation of the inner disk. Successively, we analyzed the chemical composition of silicates depending on spatial region in the disk. Finally, we sampled the parameter space of a viscous accretion disk model via Monte Carlo radiative transfer simulations to investigate the actual 3D dust density distribution of RY Tau.

Results. We constrained the orientation of the inner disk of RY Tau, finding no evidence of significant misalignment with respect to its outer disk. We identified several silicate species commonly found in protoplanetary disks and observed a depletion of amorphous dust grains toward the central protostar. By simultaneously considering the observed visibilities and the spectral energy distribution (SED), we found that an accretion disk and an optically thin envelope enshrouding the protostar fits the observations best. Radiative transfer simulations show that hot dust close to the protostar and in the line of sight (LOS) to the observer, either in the uppermost disk layers of a strongly flared disk or in a dusty envelope, is necessary to model the observations. The shadow cast by a dense innermost disk midplane on the dust further out explains the observed closure phases in the L band and (to some extent) in the M band. However, the closure phases in the N band are underestimated by our model, hinting at an additional asymmetry in the flux density distribution that is not visible at shorter wavelengths.