Discovery of concentric broken rings at sub-arcsec separations in the HD 141569A gas-rich, debris disk with VLT/SPHERE^⋆

¹ LESIA, Observatoire de Paris, PSL Research Univ., CNRS, Univ. Paris Diderot, Sorbonne Paris Cité, UPMC Paris 6, Sorbonne Univ., 5 place Jules Janssen, 92195 Meudon Cedex, France
e-mail: clement.perrot@obspm.fr
² Laboratoire AIM, CEA/DSM – CNRS – Univ. Paris Diderot, IRFU/SAp, 91191 Gif-sur-Yvette, France
³ Univ. Grenoble Alpes, IPAG, 38000 Grenoble, France
⁴ CNRS, IPAG, 38000 Grenoble, France
⁵ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁶ Space Telescope Science Institute, 3700 San Martin Dr, Baltimore MD 21218, USA
⁷ European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura, Santiago 19, Chile
⁸ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁹ Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
¹⁰ CNRS/CRAL/Observatoire de Lyon/Univ. de Lyon 1/École Normale Supérieure de Lyon, Lyon, France
¹¹ Geneva Observatory, Univ. of Geneva, Ch. des Maillettes 51, 1290 Versoix, Switzerland
¹² Aix-Marseille Univ., CNRS, LAM – Laboratoire d’Astrophysique de Marseille, UMR 7326, 13388 Marseille, France
¹³ Univ. Bordeaux, Laboratoire d’Astrophysique de Bordeaux, UMR 5804, 33270 Floirac, France
¹⁴ CNRS, LAB, UMR 5804, 33270 Floirac, France
¹⁵ Leiden Observatory, Leiden Univ., PO Box 9513, 2300 RA Leiden, The Netherlands
¹⁶ Instituto de Física y Astronomía, Facultad de Ciencias, Univ. de Valparaíso, Av. Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile
¹⁷ ICM nucleus on protoplanetary disks, Univ. de Valparaíso, Av. Gran Bretaña 1111, Valparaíso, Chile
¹⁸ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
¹⁹ Département d’Astrophysique, Géophysique et Océanographie, Univ. de Liège, Allée du Six Août 17, 4000 Liège, Belgique
²⁰ ONERA, The French Aerospace Lab BP72, 29 avenue de la Division Leclerc, 92322 Châtillon Cedex, France
²¹ European Southern Observatory, Karl Schwarzschild St., 2, 85748 Garching, Germany

Received: 26 February 2016
Accepted: 21 April 2016

Abstract

Context. Transition disks correspond to a short stage between the young protoplanetary phase and older debris phase. Along this evolutionary sequence, the gas component disappears leaving room for a dust-dominated environment where already-formed planets signpost their gravitational perturbations.

Aims. We endeavor to study the very inner region of the well-known and complex debris, but still gas-rich disk, around HD 141569A using the exquisite high-contrast capability of SPHERE at the VLT. Recent near-infrared (IR) images suggest a relatively depleted cavity within ~200 au, while former mid-IR data indicate the presence of dust at separations shorter than ~100 au.

Methods. We obtained multi-wavelength images in the near-IR in J, H2, H3 and Ks-bands with the IRDIS camera and a 0.95–1.35 μm spectral data cube with the IFS. Data were acquired in pupil-tracking mode, thus allowing for angular differential imaging.

Results. We discovered several new structures inside 1′′, of which the most prominent is a bright ring with sharp edges (semi-major axis: 0.4′′) featuring a strong north-south brightness asymmetry. Other faint structures are also detected from 0.4′′ to 1′′ in the form of concentric ringlets and at least one spiral arm. Finally, the VISIR data at 8.6 μm suggests the presence of an additional dust population closer in. Besides, we do not detect companions more massive than 1–3 mass of Jupiter.

Conclusions. The performance of SPHERE allows us to resolve the extended dust component, which was previously detected at thermal and visible wavelengths, into very complex patterns with strong asymmetries; the nature of these asymmetries remains to be understood. Scenarios involving shepherding by planets or dust-gas interactions will have to be tested against these observations.