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Observations of the young star HD 142527, whose disk is separated into inner and outer regions by a gap suggestive of the formation of a gaseous giant planet, show that accretion onto the star is maintained by a flow of gas across the gap, in agreement with dynamical models of planet formation. Gas giants leave their mark According to current theories, giant planet formation carves a deep gap in the gas and dust around a protostar, clearing most of the dust and some of the gas away to form a ring-shaped cavity. But such a gap would rapidly turn off further growth in the mass of the star unless the abundant gas from the outer disk could traverse it. This paper presents Atacama Large Millimeter/submillimeter Array observations of the disk around the young star HD 142527 that reveal diffuse CO inside the gap and denser HCO + gas along gap-crossing filaments. The estimated gas flow across the gap would be sufficient to maintain accretion onto the star at the present rate. The formation of gaseous giant planets is thought to occur in the first few million years after stellar birth. Models 1 predict that the process produces a deep gap in the dust component (shallower in the gas 2 , 3 , 4 ). Infrared observations of the disk around the young star HD 142527 (at a distance of about 140 parsecs from Earth) found an inner disk about 10 astronomical units ( au ) in radius 5 (1  au is the Earth–Sun distance), surrounded by a particularly large gap 6 and a disrupted 7 outer disk beyond 140  au . This disruption is indicative of a perturbing planetary-mass body at about 90  au . Radio observations 8 , 9 indicate that the bulk mass is molecular and lies in the outer disk, whose continuum emission has a horseshoe morphology 8 . The high stellar accretion rate 10 would deplete the inner disk 11 in less than one year, and to sustain the observed accretion matter must therefore flow from the outer disk and cross the gap. In dynamical models, the putative protoplanets channel outer-disk material into gap-crossing bridges that feed stellar accretion through the inner disk 12 . Here we report observations of diffuse CO gas inside the gap, with denser HCO + gas along gap-crossing filaments. The estimated flow rate of the gas is in the range of 7 × 10 −9 to 2 × 10 −7 solar masses per year, which is sufficient to maintain accretion onto the star at the present rate.

The vector vortex is a coronagraphic imaging mode of the recently commissioned Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) platform on the 8 m Subaru Telescope. This multi-purpose high-contrast visible and near-infrared (R- to K-band) instrument is not only intended to serve as a VLT-class \"planet-imager\" instrument in the northern hemisphere, but also to operate as a technology demonstration testbed ahead of the ELTs-era, with a particular emphasis on small inner-working angle (IWA) coronagraphic capabilities. The given priority to small-IWA imaging led to the early design choice to incorporate focal-plane phase-mask coronagraphs. In this context, a test H-band vector vortex liquid crystal polymer waveplate was provided to SCExAO, to allow a one-to-one comparison of different small-IWA techniques on the same telescope instrument, before considering further steps. Here we present a detailed overview of the vector vortex coronagraph, from its installation and performances on the SCExAO optical bench, to the on-sky results in the extreme AO regime, as of late 2016/early 2017. To this purpose, we also provide a few recent on-sky imaging examples, notably high-contrast ADI detection of the planetary-mass companion κ Andromedae b, with a signal-to-noise ratio above 100 reached in less than 10 mn exposure time.

We present a new analysis and reduction pipeline for the detection of planetary companions using Angular Differential Imaging. The pipeline uses Fourier transforms for image shifting and rotation in order to achieve very low signal loss. Furthermore it is parallelised in order to run on computer clusters of up to 1024 cores. The pipeline was developed in Geneva for the ongoing direct imaging campaign for stars with radial velocity drifts in the HARPS and CORALIE radial-velocity planet-search surveys. In addition to that, a disk mode has been implemented in the context of observations of the protoplanetary disk around HD142527.

We used multiple epochs of high-contrast imaging spectrophotometric observations to determine the atmospheric characteristics and thermal evolution of two previously detected benchmark L dwarf companions, HD 112863 B and HD 206505 B. We analyzed IRDIS and IFS data from VLT/SPHERE of each companion, both of which have dynamical masses near the stellar-substellar boundary. We compared each companion with empirical spectral standards, as well as constrained their physical properties through atmospheric model fits. From these analyses, we estimate that HD 112863 B is spectral type \\(\\rm{L}3\\pm1\\) and that HD 206505 B is spectral type \\(\\rm{L}2\\pm1\\). Using the BT-Settl atmospheric model grids, we find a bimodal solution for the atmospheric model fit of HD 112863 B, such that \\(T_{\\rm{eff}}=1757^{+37}_{-36}\\) K or \\(2002^{+23}_{-24}\\) K and \\(\\log{g}=4.973^{+0.057}_{-0.063}\\) or \\(5.253^{+0.037}_{-0.033}\\), while for HD 206505 B, \\(T_{\\rm{eff}}=1754^{+13}_{-13}\\) K and \\(\\log{g}=4.919^{+0.031}_{-0.029}\\). Comparing the bolometric luminosities of both companions with evolutionary models imply that both companions are likely above the hydrogen burning limit.

Recent observations from B-star Exoplanet Abundance Study (BEAST) have illustrated the existence of sub-stellar companions around very massive stars. In this paper, we present the detection of two lower mass companions to a relatively nearby (\\(148.7^{+1.5}_{-1.3}\\) pc), young (\\(17^{+3}_{-4}\\) Myr), bright (V=\\(6.632\\pm0.006\\) mag), \\(2.58\\pm0.06~ M_{\\odot}\\) B9V star HIP 81208 residing in the Sco-Cen association, using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument at the Very Large Telescope (VLT) in Chile. Analysis of the photometry obtained gives mass estimates of \\(67^{+6}_{-7}~M_J\\) for the inner companion and \\(0.135^{+0.010}_{-0.013}~M_{\\odot}\\) for the outer companion, indicating the former to be most likely a brown dwarf and the latter to be a low-mass star. The system is compact but unusual, as the orbital planes of the two companions are likely close to orthogonal. The preliminary orbital solutions we derived for the system indicate that the star and the two companions are likely in a Kozai resonance, rendering the system dynamically very interesting for future studies.

RISTRETTO is a visible high-resolution spectrograph fed by an extreme adaptive optics (AO) system, to be proposed as a visitor instrument on ESO VLT. The main science goal of RISTRETTO is to pioneer the detection and atmospheric characterisation of exoplanets in reflected light, in particular the temperate rocky planet Proxima b. RISTRETTO will be able to measure albedos and detect atmospheric features in a number of exoplanets orbiting nearby stars for the first time. It will do so by combining a high-contrast AO system working at the diffraction limit of the telescope to a high-resolution spectrograph, via a 7-spaxel integral-field unit (IFU) feeding single-mode fibers. Further science cases for RISTRETTO include the study of accreting protoplanets such as PDS70b/c through spectrally-resolved H-alpha emission, and spatially-resolved studies of Solar System objects such as icy moons and the ice giants Uranus and Neptune. The project is in the manufacturing phase for the spectrograph sub-system, and the preliminary design phase for the AO front-end. Specific developments for RISTRETTO include a novel coronagraphic IFU combining a phase-induced amplitude apodizer (PIAA) to a 3D-printed microlens array feeding a bundle of single-mode fibers. It also features an XAO system with a dual wavefront sensor aiming at high robustness and sensitivity, including to pupil fragmentation. RISTRETTO is a pathfinder instrument in view of similar developments at the ELT, in particular the SCAO-IFU mode of ELT-ANDES and the future ELT-PCS instrument.

Reference-star differential imaging (RDI) is a promising technique in high-contrast imaging that is thought to be more sensitive to exoplanets and disks than angular differential imaging (ADI) at short angular separations (i.e., <0.3\"). However, it is unknown whether the performance of RDI on ground-based instruments can be improved by using all the archival data to optimize the subtraction of stellar contributions. We characterize the performance of RDI on SPHERE/IRDIS data in direct imaging of exoplanets and disks. We made use of all the archival data in H23 obtained by SPHERE/IRDIS in the past five years to build a master reference library and perform RDI. In the point-source detection, RDI can outperform ADI at small angular separations (<0.4\") if the observing conditions are around the median conditions of our master reference library. On average, RDI has a gain of ~0.8 mag over ADI at 0.15\" separation for observations under median conditions. We demonstrate that including more reference targets in the master reference library can indeed help to improve the performance of RDI. In disk imaging, RDI can reveal more disk features and provide a more robust recovery of the disk morphology. We resolve 33 disks in total intensity (19 planet-forming disks and 14 debris disks), and 4 of them can only be detected with RDI. Two disks are resolved in scattered light for the first time. Three disks are detected in total intensity for the first time. The master reference library we built in this work can be easily implemented into legacy or future SPHERE surveys to perform RDI, achieving better performance than that of ADI. To obtain optimal RDI gains over ADI, we recommend future observations be carried out under seeing conditions of 0.6\"-0.8\".

Young M-type binaries are particularly useful for precise isochronal dating by taking advantage of their extended pre-main sequence evolution. Orbital monitoring of these low-mass objects becomes essential in constraining their fundamental properties, as dynamical masses can be extracted from their Keplerian motion. Here, we present the combined efforts of the AstraLux Large Multiplicity Survey, together with a filler sub-programme from the SpHere INfrared Exoplanet (SHINE) project and previously unpublished data from the FastCam lucky imaging camera at the Nordical Optical Telescope (NOT) and the NaCo instrument at the Very Large Telescope (VLT). Building on previous work, we use archival and new astrometric data to constrain orbital parameters for 20 M-type binaries. We identify that eight of the binaries have strong Bayesian probabilities and belong to known young moving groups (YMGs). We provide a first attempt at constraining orbital parameters for 14 of the binaries in our sample, with the remaining six having previously fitted orbits for which we provide additional astrometric data and updated Gaia parallaxes. The substantial orbital information built up here for four of the binaries allows for direct comparison between individual dynamical masses and theoretical masses from stellar evolutionary model isochrones, with an additional three binary systems with tentative individual dynamical mass estimates likely to be improved in the near future. We attained an overall agreement between the dynamical masses and the theoretical masses from the isochrones based on the assumed YMG age of the respective binary pair. The two systems with the best orbital constrains for which we obtained individual dynamical masses, J0728 and J2317, display higher dynamical masses than predicted by evolutionary models.

We present orbital fits and dynamical masses for HIP 113201AB and HIP 36985AB, two M1 + mid-M dwarf binary systems monitored as part of the SPHERE SHINE survey. To robustly determine ages via gyrochronology, we undertook a photometric monitoring campaign for HIP 113201 and for GJ 282AB, the two wide K star companions to HIP 36985, using the 40 cm Remote Observatory Atacama Desert (ROAD) telescope. We adopt ages of 1.2\\(\\)0.1 Gyr for HIP 113201AB and 750\\(\\)100 Myr for HIP 36985AB. To derive dynamical masses for all components of these systems, we used parallel-tempering Markov Chain Monte Carlo sampling to fit a combination of radial velocity, direct imaging, and Gaia and Hipparcos astrometry. Fitting the direct imaging and radial velocity data for HIP 113201 yields a primary mass of 0.54\\(\\)0.03 M\\(_\\), fully consistent with its M1 spectral type, and a secondary mass of 0.145\\(\\) M\\(_\\). The secondary masses derived with and without including Hipparcos/Gaia data are more massive than the 0.1 M\\(_\\) estimated mass from the photometry of the companion. An undetected brown dwarf companion to HIP 113201B could be a natural explanation for this apparent discrepancy. At an age \\(>\\)1 Gyr, a 30 M\\(_Jup\\) companion to HIP 113201B would make a negligible (\\(<\\)1\\(\\%\\)) contribution to the system luminosity, but could have strong dynamical impacts. Fitting the direct imaging, radial velocity, and Hipparcos/Gaia proper motion anomaly for HIP 36985AB, we find a primary mass of 0.54\\(\\)0.01 M\\(_\\) and a secondary mass of 0.185\\(\\)0.001 M\\(_\\) which agree well with photometric estimates of component masses, the masses estimated from \\(M_K\\)-- mass relationships for M dwarf stars, and previous dynamical masses in the literature.

While the sample of confirmed exoplanets continues to increase, the population of transiting exoplanets around early-type stars is still limited. These planets allow us to investigate the planet properties and formation pathways over a wide range of stellar masses and study the impact of high irradiation on hot Jupiters orbiting such stars. We report the discovery of TOI-615b, TOI-622b, and TOI-2641b, three Saturn-mass planets transiting main sequence, F-type stars. The planets were identified by the Transiting Exoplanet Survey Satellite (TESS) and confirmed with complementary ground-based and radial velocity observations. TOI-615b is a highly irradiated (\\(\\sim\\)1277 \\(F_{\\oplus}\\)) and bloated Saturn-mass planet (1.69$^{+0.05}_{-0.06}$$R_{Jup}\\( and 0.43\\)^{+0.09}_{-0.08}$$M_{Jup}\\() in a 4.66 day orbit transiting a 6850 K star. TOI-622b has a radius of 0.82\\)^{+0.03}_{-0.03}$$R_{Jup}\\( and a mass of 0.30\\)^{+0.07}_{-0.08}\\(~\\)M_{Jup}\\( in a 6.40 day orbit. Despite its high insolation flux (\\)\\sim\\(600 \\)F_{\\oplus}\\(), TOI-622b does not show any evidence of radius inflation. TOI-2641b is a 0.39\\)^{+0.02}_{-0.04}$$M_{Jup}\\( planet in a 4.88 day orbit with a grazing transit (b = 1.04\\)^{+0.05}_{-0.06 }\\() that results in a poorly constrained radius of 1.61\\)^{+0.46}_{-0.64}$$R_{Jup}\\(. Additionally, TOI-615b is considered attractive for atmospheric studies via transmission spectroscopy with ground-based spectrographs and \\)\\textit{JWST}$. Future atmospheric and spin-orbit alignment observations are essential since they can provide information on the atmospheric composition, formation and migration of exoplanets across various stellar types.