A narrow, edge-on disk resolved around HD 106906 with SPHERE^⋆,⋆⋆

¹ Univ. Grenoble Alpes, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG, UMR 5274), 38000 Grenoble, France
e-mail: lagrange@obs.ujf-grenoble.fr
² CNRS, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG, UMR 5274), 38000 Grenoble, France
³ CRAL, UMR 5574, CNRS, Université Lyon 1, 9 avenue Charles André, 69561 Saint Genis Laval Cedex, France
⁴ Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
⁵ INAF−Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁶ European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura, Santiago 19, Chile
⁷ Max Planck Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁸ Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
⁹ ICM nucleus on protoplanetary disks, Universidad de Valparaíso, Av. Gran Bretaña 1111, Valparaíso, Chile
¹⁰ Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065, USA
¹¹ LESIA, Observatoire de Paris, CNRS, Université Paris Diderot, Université Pierre et Marie Curie, 5 place Jules Janssen, 92190 Meudon, France
¹² UMI-FCA, CNRS/INSU (UMI3386), France
¹³ Sterrewacht Leiden, PO Box 9513, Niels Bohrweg 2, 2300 RA Leiden, The Netherlands
¹⁴ Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
¹⁵ Geneva Observatory, University of Geneva, Ch. des Maillettes 51, 1290 Versoix, Switzerland
¹⁶ Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden
¹⁷ Observatoire de Haute-Provence, OH/CNRS, 04870 St. Michel l’ Observatoire, France
¹⁸ Laboratoire Lagrange, Université de Nice-Sophia Antipolis, Observatoire de la Côte d’Azur, CNRS UMR 7293, Nice Cedex 44, France
¹⁹ Onera−The French Aerospace Lab, 92322 Châtillon, France

Received: 28 August 2015
Accepted: 28 September 2015

Abstract

Context. HD 106906AB is the only young binary system so far around which a planet has been imaged and a debris disk has been shown to exist, thanks to a strong IR excess. As such, it represents a unique opportunity for studying the dynamics of young planetary systems.

Aims. We aim at further investigating the close (tens of au scales) environment of the HD 106906AB system.

Methods. We used the extreme adaptive-optics-fed, high-contrast imager SPHERE that has recently been installed on the VLT to observe HD 106906. Both the IRDIS imager and the Integral Field Spectrometer were used.

Results. We discovered a highly inclined, ring-like disk at a distance of 65 au from the star. The disk shows a strong brightness asymmetry with respect to its semi-major axis. It shows a smooth outer edge, compatible with ejection of small grains by the stellar radiation pressure. We show furthermore that the planet’s projected position is significantly above the PA of the disk. Given the determined disk inclination, it is not excluded, however, that the planet could still orbit within the disk plane if at a large separation (2000−3000 au). We identified several additional point sources in the SPHERE/IRDIS field of view that appear to be background objects. We compare this system with other debris disks sharing similarities, and we briefly discuss the present results in the framework of dynamical evolution.