Shadows and spirals in the protoplanetary disk HD 100453 ^⋆

¹ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
e-mail: Myriam.Benisty@univ-grenoble-alpes.fr
² Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
³ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁴ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
⁵ Institute for Theoretical Astrophysics, Heidelberg University, Albert-Ueberle-Strasse 2, 69120 Heidelberg, Germany
⁶ CRAL, UMR 5574, CNRS, Université Lyon 1, 9 avenue Charles André, 69561 Saint-Genis-Laval Cedex, France
⁷ SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
⁸ Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
⁹ Institute of Astronomy, Madingley Road, Cambridge CB3 OHA, UK
¹⁰ Max-Planck-Institut fur Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany
¹¹ Universidad Autonónoma de Madrid, Dpto. Física Teórica, Facultad de Ciencias, Campus de Cantoblanco, 28049 Madrid, Spain
¹² Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
¹³ Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
¹⁴ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, 1058 Santiago, Chile
¹⁵ LESIA, Observatoire de Paris-Meudon, CNRS, Université Pierre et Marie Curie, Université Paris Didierot, 5 place Jules Janssen, 92195 Meudon, France
¹⁶ INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
¹⁷ Institute for Astronomy, University of Edinburgh, Blackford Hill View, Edinburgh EH9 3HJ, UK
¹⁸ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹⁹ Aix-Marseille Univ, CNRS, LAM, Laboratoire d’Astrophysique de Marseille, 13013 Marseille, France
²⁰ INAF–Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
²¹ ONERA – 29 avenue de la Division Leclerc, 92322 Chatillon Cedex, France
²² Geneva Observatory, Univ. of Geneva, Chemin des Maillettes 51, 1290 Versoix, Switzerland

Received: 27 September 2016
Accepted: 28 October 2016

Abstract

Context. Understanding the diversity of planets requires studying the morphology and physical conditions in the protoplanetary disks in which they form.

Aims. We aim to study the structure of the ~10 Myr old protoplanetary disk HD 100453, to detect features that can trace disk evolution and to understand the mechanisms that drive these features.

Methods. We observed HD 100453 in polarized scattered light with VLT/SPHERE at optical (0.6 μm, 0.8 μm) and near-infrared (1.2 μm) wavelengths, reaching an angular resolution of ~0.02′′, and an inner working angle of ~0.09′′.

Results. We spatially resolve the disk around HD 100453, and detect polarized scattered light up to ~0.42′′ (~48 au). We detect a cavity, a rim with azimuthal brightness variations at an inclination of ~38° with respect to our line of sight, two shadows and two symmetric spiral arms. The spiral arms originate near the location of the shadows, close to the semi major axis. We detect a faint feature in the SW that can be interpreted as the scattering surface of the bottom side of the disk, if the disk is tidally truncated by the M-dwarf companion currently seen at a projected distance of ~119 au. We construct a radiative transfer model that accounts for the main characteristics of the features with an inner and outer disk misaligned by ~72°. The azimuthal brightness variations along the rim are well reproduced with the scattering phase function of the model. While spirals can be triggered by the tidal interaction with the companion, the close proximity of the spirals to the shadows suggests that the shadows could also play a role. The change in stellar illumination along the rim induces an azimuthal variation of the scale height that can contribute to the brightness variations.

Conclusions. Dark regions in polarized images of transition disks are now detected in a handful of disks and often interpreted as shadows due to a misaligned inner disk. However, the origin of such a misalignment in HD 100453, and of the spirals, is still unclear, and might be due to a yet-undetected massive companion inside the cavity, and on an inclined orbit. Observations over a few years will allow us to measure the spiral pattern speed, and determine if the shadows are fixed or moving, which may constrain their origin.