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Debris Disks

New disk discovered with VLT/SPHERE around the M star GSC 07396-00759

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Debris disks are usually detected through the infrared excess over the photospheric level of their host star. The most favorable stars for disk detection are those with spectral types between A and K, while the statistics for debris disks detected around low-mass M-type stars is very low, either because they are rare or because they are more difficult to detect. Terrestrial planets, on the (...)

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Resolving faint structures in the debris disk around TWA7

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Debris disks are the intrinsic by-products of the star and planet formation processes. Most likely due to instrumental limitations and their natural faintness, little is known about debris disks around low-mass stars, especially when it comes to spatially resolved observations. We present new VLT/SPHERE IRDIS Dual-Polarization Imaging (DPI) observations in which we detect the dust ring around (...)

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Observations of fast-moving features in the debris disk of AU Mic on a three-year timescale : Confirmation and new discoveries

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The nearby and young M star AU Mic is surrounded by a debris disk in which we previously identified a series of large-scale arch-like structures that have never been seen before in any other debris disk and that move outward at high velocities. We initiated a monitoring program with the following objectives : 1) track the location of the structures and better constrain their projected speeds, (...)

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The HIP 79977 debris disk in polarized light

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Nov. 2017 : Debris disks are observed around 10 to 20% of FGK main-sequence stars as infrared excess emission. They are important signposts for the presence of colliding planetesimals and therefore provide important information about the evolution of planetary systems. Direct imaging of such disks reveals their geometric structure and constrains their dust-particle properties. We present (...)

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Near-infrared scattered light properties of the HR 4796 A dust ring. A measured scattering phase function from 13.6° to 166.6°

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Mar. 2017 : HR 4796 A is surrounded by a debris disc, observed in scattered light as an inclined ring with a high surface brightness. Past observations have raised several questions. First, a strong brightness asymmetry detected in polarised reflected light has recently challenged our understanding of scattering by the dust particles in this system. Secondly, the morphology of the ring (...)

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Dynamical models to explain observations with SPHERE in planetary systems with double debris belts

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Oct. 2017 : A large number of systems harboring a debris disk show evidence for a double belt architecture. One hypothesis for explaining the gap between the belts is the presence of one or more planets dynamically carving it. This work aims to investigate this scenario in systems harboring two components debris disks. All the targets in the sample were observed with the SPHERE instrument (...)

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SPHERE/SHINE reveals concentric rings in the debris disk of HIP 73145

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May. 2017 : Debris disks correspond to the final evolutionary stage of circumstellar disks around young stars. Gas-deprived structures seen in debris disks are normally, but not always, attributed to dynamical interactions in young planetary systems. The debris disk of HIP 73145 has been detected in scattered light in the near-IR, and at far-IR wavelengths before, but no substructure has (...)

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Fast-moving features in the debris disk around AU Microscopii

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Oct. 2015 : In the 1980s, excess infrared emission was discovered around main-sequence stars ; subsequent direct-imaging observations revealed orbiting disks of cold dust to be the source. These `debris disks’ were thought to be by-products of planet formation because they often exhibited morphological and brightness asymmetries that may result from gravitational perturbation by planets. This (...)

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Azimuthal asymmetries in the debris disk around HD61005

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Jun. 2016 : Debris disks offer valuable insights into the latest stages of circumstellar disk evolution, and can possibly help us to trace the outcomes of planetary formation processes. In the age range 10 to 100\,Myr, most of the gas is expected to have been removed from the system, giant planets (if any) must have already been formed, and the formation of terrestrial planets may be (...)

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

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May 2016 : 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.

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

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Feb. 2016 : 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.

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