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Exoplanets/Brown dwarfs

Imaging radial velocity planets with SPHERE

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We present observations with the planet finder SPHERE of a selected sample of the most promising radial velocity (RV) companions for high-contrast imaging. Using a Monte Carlo simulation to explore all the possible inclinations of the orbit of wide RV companions, we identified the systems with companions that could potentially be detected with SPHERE. We found the most favorable RV systems to (...)

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The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data

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The G-type star GJ504A is known to host a 3 to 35 MJup companion whose temperature, mass, and projected separation all contribute to make it a test case for the planet formation theories and for atmospheric models of giant planets and light brown dwarfs. We collected data from the CHARA interferometer, SOPHIE spectrograph, and VLT/SPHERE high contrast imager to revisit the properties of the (...)

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Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk

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Aims : We aim to characterize the orbital and atmospheric properties of PDS 70 b, which was first identified on May 2015 in the course of the SHINE survey with SPHERE, the extreme adaptive-optics instrument at the VLT. Methods : We obtained new deep SPHERE/IRDIS imaging and SPHERE/IFS spectroscopic observations of PDS 70 b. The astrometric baseline now covers 6 years which allows us to (...)

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Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70

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Young circumstellar are of prime interest to understand the physical and chemical conditions under which planet formation takes place. Only very few detections of planet candidates within these disks exist, and most of them are currently suspected to be disk features. In this context, the transition disk around the young star PDS 70 is of particular interest, due to its large gap identified (...)

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Dynamical masses of M-dwarf binaries in young moving groups I - The case of TWA 22 and GJ 2060

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Context. Evolutionary models are widely used to infer the mass of stars, brown dwarfs, and giant planets. Their predictions are thought to be less reliable at young ages (< 200 Myr) and in the low-mass regime (< 1 M⊙). GJ 2060 AB and TWA 22 AB are two rare astrometric M-dwarf binaries respectively members of the AB Doradus (AB Dor) and Beta Pictoris (à Pic) moving groups. As their (...)

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New spectro-photometric characterization of the substellar object HR 2562 B using SPHERE

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Aims. HR 2562 is an F5V star located at ∼33 pc from the Sun hosting a substellar companion that was discovered using the Gemini planet imager (GPI) instrument. The main objective of the present paper is to provide an extensive characterization of the substellar companion, by deriving its fundamental properties. Methods. We observed HR 2562 with the near-infrared branch composed by the (...)

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VLT/SPHERE astrometric confirmation and orbital analysis of the brown dwarf companion HR 2562 B

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Context. A low-mass brown dwarf has been recently imaged around HR 2562 (HD 50571), a star hosting a debris disk resolved in the far infrared. Interestingly, the companion location is compatible with an orbit coplanar with the disk and interior to the debris belt. This feature makes the system a valuable laboratory to analyze the formation of substellar companions in a circumstellar disk and (...)

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Investigating the young Solar System analog HD95086

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HD95086 (A8V, 17Myr) hosts a rare planetary system for which a multi-belt debris disk and a giant planet of 4-5MJup have been directly imaged. Our study aims to characterize the physical and orbital properties of HD95086b, search for additional planets at short and wide orbits and image the cold outer debris belt in scattered light. We used HARPS at the ESO 3.6m telescope to monitor the (...)

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Discovery of a brown dwarf companion to the star HIP 64892

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We report the discovery of a bright, brown dwarf companion to the star HIP 64892, imaged with VLT/SPHERE during the SHINE exoplanet survey. The host is a B9.5V member of the Lower-Centaurus-Crux subgroup of the Scorpius Centaurus OB association. The measured angular separation of the companion (1.2705±0.0023") corresponds to a projected distance of 159±12 AU. We observed the target with the (...)

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Characterizing HR 3549 B using SPHERE

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Oct. 2016 : In this work, we characterize the low-mass companion of the A0 field star HR 3549. We observed HR 3549B in imaging mode with the near-infrared branch (IFS and IRDIS) of SPHERE at the VLT, with IFS in YJ mode and IRDIS in the H band. We also acquired a medium-resolution spectrum with the IRDIS long-slit spectroscopy mode. The data were reduced using the dedicated SPHERE GTO (...)

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In-depth study of moderately young but extremely red, very dusty substellar companion HD206893B

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Sep. 2017 : The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate the atypical properties of the companion, which has the reddest near-infrared colours among all known substellar objects, either orbiting a star or isolated, and we provide a comprehensive characterisation of the host (...)

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Discovery of a warm, dusty giant planet around HIP 65426

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Sep. 2017 : The SHINE program is a high-contrast near-infrared survey of 600 young, nearby stars aimed at searching for and characterizing new planetary systems using VLT/SPHERE’s unprecedented high-contrast and high-angular-resolution imaging capabilities. It is also intended to place statistical constraints on the rate, mass and orbital distributions of the giant planet population at large (...)

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Orbiting a binary : SPHERE characterisation of the HD 284149 system

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Jul. 2017 : In this paper we present the results of the SPHERE observation of the HD 284149 system, aimed at a more detailed characterisation of both the primary and its brown dwarf companion. We observed HD 284149 in the near-infrared with SPHERE, using the imaging mode (IRDIS+IFS) and the long-slit spectroscopy mode (IRDIS-LSS). The data were reduced using the dedicated SPHERE pipeline, and (...)

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Spectral and atmospheric characterization of 51 Eridani b using VLT/SPHERE

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Jul. 2017 : 51 Eridani b is an exoplanet around a young (20 Myr) nearby (29.4 pc) F0-type star, which was recently discovered by direct imaging. It is one of the closest direct imaging planets in angular and physical separation ( 0.5’’, 13 au) and is well suited for spectroscopic analysis using integral field spectrographs. We aim to refine the atmospheric properties of the known giant planet (...)

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First light of the VLT planet finder SPHERE. I. Detection and characterization of the sub-stellar companion GJ 758 B

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Mar. 2016 : GJ 758 B is a brown dwarf companion to a nearby (15.76%) solar-type, metal-rich (M / H = + 0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest ( 600 K) companion ever directly imaged around a neighboring star. We present new high-contrast data obtained during the commissioning of the (...)

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First light of the VLT planet finder SPHERE II. The physical properties and the architecture of the young systems PZ Tel and HD 1160 revisited with VLT/SPHERE

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Mar. 2016 : The young systemsPZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of the new planet finder of the Very Large Telescope (VLT) SPHERE with several imaging and spectroscopic modes.

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First light of the VLT planet finder SPHERE III. New spectrophotometry and astrometry of the HR 8799 exoplanetary system

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Mar. 2016 : The planetary system discovered around the young A-type HR 8799 provides a unique laboratory to : a) test planet formation theories ; b) probe the diversity of system architectures at these separations, and c) perform comparative (exo)planetology.

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First light of the VLT planet finder SPHERE. IV. Physical and chemical properties of the planets around HR8799

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Mar. 2016 : The system of fourplanets discovered around the intermediate-mass star HR8799 offers a unique opportunity to test planet formation theories at large orbital radii and to probe the physics and chemistry at play in the atmospheres of self-luminous young ( 30 Myr) planets. We recently obtained new photometry of the four planets and low-resolution (R 30) spectra of HR8799 d and e with (...)

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