The complex inner disk of the Herbig Ae star HD 100453 with VLTI/MATISSE

¹ Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
² Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, HUN-REN, Konkoly-Thege Miklós út 15-17, 1121 Budapest, Hungary
³ CSFK, MTA Centre of Excellence, Konkoly-Thege Miklós út 15-17, 1121 Budapest, Hungary
⁴ Anton Pannekoek Institute for Astronomy, University of Amsterdam, The Netherlands
⁵ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁶ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, France
⁷ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁸ NASA Goddard Space Flight Center, Astrophysics Division, Greenbelt, MD 20771, USA
⁹ STAR Institute, University of Liège, Liège, Belgium
¹⁰ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
¹¹ Institute of Theoretical Physics and Astrophysics, University of Kiel, Leibnizstr. 15, 24118 Kiel, Germany
¹² AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France
¹³ SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
¹⁴ Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721, USA

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Received: 21 December 2024
Accepted: 4 November 2025

Abstract

Context. The inner regions of planet-forming disks hold invaluable insights for our understanding of planet formation. The inner disk regions that might be affected by already formed planets are of particular interest. The disk around the Herbig star HD 100453 presents one such environment, with an inner disk that is significantly misaligned with respect to the outer disk.

Aims. This paper expands the existing H band (PIONIER) and K band (GRAVITY) interferometric studies of the inner disk of HD 100453 to the L band with the MATISSE VLTI instrument. Based on snapshot data spanning approximately four years, we aim to understand the inner disk structures and their potential time evolution better.

Methods. Based on the MATISSE data we obtained, we used a combination of analytical models and image reconstruction to constrain the disk structure. Additionally, we fitted a temperature gradient model to the selected wavelength range of PIONIER, GRAVITY, and MATISSE to derive the physical properties of the inner regions.

Results. Our parametric model determined an inclination of ≈47.5° and a position angle of ≈83.6°, which corroborates the strong misalignment of the inner to the outer disk. From the symmetric temperature gradient, we derive an inner disk radius of ≈0.27 au, with dust surface densities of Σ_subl ≈ 10^−3.2 g/cm² and a vertical optical depth τ_z,subl ≈ 0.1-0.06. Same-night MATISSE and GRAVITY observations show directional discrepancies that are inconsistent with a first-order azimuthally modulation ring. This indicates that higher-order asymmetries are required to explain the interferometric signals. This interpretation is further supported by a MATISSE snapshot image reconstruction that revealed a two-component asymmetric structure.

Conclusions. The chromatic interferometric data reveal that higher-order asymmetries are probably required to explain the inner disk of HD 100453, which suggests a possible origin in dynamic interactions or disk instabilities. Coordinated multi-wavelength infrared interferometric observations with GRAVITY and MATISSE will be crucial to confirm these findings and uncover their underlying nature.