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Exoplanets/Brown dwarfs

The search for disks or planetary objects around directly imaged companions : A candidate around DH Tau B

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In recent decades, thousands of substellar companions have been discovered with both indirect and direct methods of detection. In this paper, we focus our attention on substellar companions detected with the direct imaging technique, with the primary goal of investigating their close surroundings and looking for additional companions and satellites, as well as disks and rings. Any such (...)

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The SPHERE infrared survey for exoplanets (SHINE) III. The demographics of young giant exoplanets below 300 au with SPHERE

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The SpHere INfrared Exoplanet (SHINE) project is a 500-star survey performed with SPHERE on the Very Large Telescope for the purpose of directly detecting new substellar companions and understanding their formation and early evolution. Here we present an initial statistical analysis for a subsample of 150 stars spanning spectral types from B to M that are representative of the full SHINE (...)

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Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

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Context. Detecting and characterizing substellar companions for which the luminosity, mass, and age can be determined independently is of utter importance to test and calibrate the evolutionary models due to uncertainties in their formation mechanisms. HD 19467 is a bright and nearby star hosting a cool brown dwarf companion detected with RV and imaging, making it a valuable object for such (...)

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Searching for the near infrared counterpart of Proxima c using multi-epoch high contrast SPHERE data at VLT

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Proxima Centauri is known to host an earth-like planet in its habitable zone ; very recently a second candidate planet was proposed based on radial velocities. At quadrature, the expected projected separation of this new candidate is larger than 1 arcsec, making it a potentially interesting target for direct imaging. While difficult, identification of the optical counterpart of this planet (...)

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RefPlanets : Search for reflected light from extra-solar planets with SPHERE/ZIMPOL

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RefPlanets is a guaranteed time observation (GTO) programme that uses the Zurich IMaging POLarimeter (ZIMPOL) of SPHERE/VLT for a blind search for exoplanets in wavelengths from 600-900 nm. The goals of this study are the characterization of the unprecedented high polarimetic contrast and polarimetric precision capabilities of ZIMPOL for bright targets, the search for polarized reflected (...)

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VLT/SPHERE exploration of the young multiplanetary system PDS70

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Context. PDS 70 is a young (5.4 Myr), nearby ( 113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) allowed us to detect a planetary mass companion, PDS70b, within the disk cavity. Moreover, observations in H_alpha with MagAO and MUSE revealed emission associated to PDS70b and to another new companion candidate, (...)

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Determining mass limits around HD 163296 through SPHERE direct imaging data

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HD163296 is a Herbig Ae/Be star known to host a protoplanetary disk with a ringed structure. To explain the disk features, previous works proposed the presence of planets embedded into the disk. We have observed HD163296 with the near-infrared (NIR) branch of SPHERE composed by IRDIS and IFS with the aim to put tight constraints on the presence of substellar companions around this star. (...)

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Constraining the properties of HD 206893 B. A combination of radial velocity, direct imaging, and astrometry data

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High contrast imaging enables the determination of orbital parameters for substellar companions (planets, brown dwarfs) from the observed relative astrometry and the estimation of model and age-dependent masses from their observed magnitudes or spectra. Combining astrometric positions with radial velocity gives direct constraints on the orbit and on the dynamical masses of companions. A brown (...)

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Hint of curvature in the orbital motion of the exoplanet 51 Eridani b using 3 years of VLT/SPHERE monitoring

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Context. The 51 Eridani system harbors a complex architecture with its primary star forming a hierarchical system with the binary GJ 3305AB at a projected separation of 2000 au, a giant planet orbiting the primary star at 13 au, and a low-mass debris disk around the primary star with possibly a cold component and a warm component inferred from the spectral energy distribution. Aims. We aim to (...)

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Exploring the R CrA environment with SPHERE : Discovery of a new stellar companion

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Aims. R Coronae Australis (R CrA) is the brightest star of the Coronet nebula of the Corona Australis (CrA) star forming region. It has very red colors, probably due to dust absorption and it is strongly variable. High contrast instruments allow for an unprecedented direct exploration of the immediate circumstellar environment of this star. Methods. We observed R CrA with the near-IR channels (...)

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SPHERE dynamical and spectroscopic characterization of HD142527B

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We detect the accreting low-mass companion HD142527B at a separation of 73 mas (11.4 au) from the star. No other companions with mass greater than 10 MJ are visible in the field of view of IFS (\sim 100 au centered on the star) or in the IRDIS field of view (\sim 400 au centered on the star). Measurements from IFS, SAM IFS, and IRDIS suggest an M6 spectral type for HD142527B, with an (...)

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Spectral and orbital characterisation of the directly imaged giant planet HIP 65426 b

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HIP 65426 b is a recently discovered exoplanet imaged during the course of the SPHERE-SHINE survey. Here we present new $L’$ and $M’$ observations of the planet from the NACO instrument at the VLT from the NACO-ISPY survey, as well as a new $Y-H$ spectrum and $K$-band photometry from SPHERE-SHINE. Using these data, we confirm the nature of the companion as a warm, dusty planet with a mid-L (...)

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A search for accreting young companions embedded in circumstellar disks : High-contrast H alpha imaging with VLT/SPHERE

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Aims : We want to detect and quantify observables related to accretion processes occurring locally in circumstellar disks, which could be attributed to young forming planets. We focus on objects known to host protoplanet candidates and/or disk structures thought to be the result of interactions with planets. Methods : We analyzed observations of 6 young stars (age $3.5-10$ Myr) and their (...)

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beta Pictoris b post conjunction detection with VLT/SPHERE

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Context. With an orbital distance comparable to that of Saturn in the solar system, β Pictoris b is the closest (semi-major axis ≃ 9 au) exoplanet imaged orbiting a star. Thus it offers unique opportunities of detailed studies of its orbital, physical and atmospheric properties, and of disk-planet interactions. With the exception of the discovery observations from 2003 with NaCo at VLT, all (...)

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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 integral (...)

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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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