We present aperture masking interferometry (AMI) observations of the star HIP 65426 at 3.8 μ m, as part of the JWST Direct Imaging Early Release Science program, obtained using the Near Infrared Imager and Slitless Spectrograph instrument. This mode provides access to very small inner working angles (even separations slightly below the Michelson limit of 0.5 λ / D for an interferometer), which are inaccessible with the classical inner working angles of the JWST coronagraphs. When combined with JWST’s unprecedented infrared sensitivity, this mode has the potential to probe a new portion of parameter space across a wide array of astronomical observations. Using this mode, we are able to achieve a 5 σ contrast of Δ m F380M ∼ 7.62 ± 0.13 mag relative to the host star at separations ​​​​​≳0 . ″ 07 , and the contrast deteriorates steeply at separations ≲0 . ″ 07. However, we detect no additional companions interior to the known companion HIP 65426b (at separation ∼0 . ″ 82 or 8 7 − 31 + 108 au ). Our observations thus rule out companions more massive than 10–12 M Jup at separations ∼10–20 au from HIP 65426, a region out of reach of ground- or space-based coronagraphic imaging. These observations confirm that the AMI mode on JWST is sensitive to planetary mass companions at close-in separations (≳0 . ″ 07), even for thousands of more distant stars at ∼100 pc, in addition to the stars in the nearby young moving groups and associations, as stated in previous works. This result will allow the planning and successful execution of future observations to probe the inner regions of nearby stellar systems, opening an essentially unexplored parameter space.

Context . About a year ago, a super-Jovian planet was directly imaged around the nearby young solar-type star AF Lep. The 2.8 M Jup planet orbiting at a semimajor axis of 8.2 au matches the predicted location based on the HIPPARCOS- Gaia astrometric acceleration. Aims . Our aim is to expand the atmospheric exploration of AF Lep b by modeling all available observations obtained with SPHERE at VLT (in the range 0.95–1.65, at 2.105, and at 2.253 µm), and NIRC2 at Keck (at 3.8 µm) with self-consistent atmospheric models. Methods . To understand the physical properties of this exoplanet, we used ForMoSA . This forward-modeling code compares observations with grids of pre-computed synthetic atmospheric spectra using Bayesian inference methods. We used Exo-REM, an atmospheric radiative-convective equilibrium model, including the effects of nonequilibrium processes and clouds. Results . From the atmospheric modeling we derived solutions at the low T eff of ~750 K. Our analysis also favors a metal-rich atmosphere (>0.4) and solar to super-solar carbon-to-oxygen ratio (~0.6). We tested the robustness of the estimated values for each parameter by cross-validating our models using the leave-one-out strategy, where all points are used iteratively as validation points. Our results indicate that the photometry point at 3.8 µm strongly drives the metal-rich and super-solar carbon-to-oxygen solutions. Conclusions . Our atmospheric forward-modeling analysis strongly supports the planetary nature of AF Lep b. Its spectral energy distribution is consistent with that of a young, cold, early-T super-Jovian planet. We recover physically consistent solutions for the surface gravity and radius, which allows us to reconcile atmospheric forward modeling with evolutionary models, in agreement with the previously published complementary analysis done by retrievals. Finally, we identified that future data at longer wavelengths are necessary before we can conclude about the metal-rich nature of AF Lep b.

We present a photometric variability survey of young planetary-mass objects using the New Technology Telescope in the Js and Ks bands. Surface gravity plays an important role in the atmospheric structure of brown dwarfs, as young low gravity L dwarfs have a higher variability rate than field L dwarfs. In this study, we extend variability studies to young T-type planetary-mass objects and investigate the effects of surface gravity on the variability of L and T dwarfs across a large sample. We conduct continuous monitoring for 18 objects with spectral types from L5 to T8 and detect four new variables and two variable candidates. Combining with previous variability surveys of field and young L and T objects, we find that young objects tend to be more variable than field objects within peak-to-peak variability amplitude ranges of 0.5-10 per cent and period ranges of 1.5-20 hr. For the first time, we constrain the variability rate of young T dwarfs to be 56 per cent compared to 25 per cent for field T dwarfs. Both field and young samples have higher variability rates at the L/T transition than outside the L/T transition. The differences in the variability rates between field and young samples are about 1 sigma and therefore larger sample sizes are needed to confirm and refine the results. Besides the L/T transition, young L dwarfs with strong variability tend to assemble in a narrow spectral type range of L6-L7.5. This work supports the critical role of surface gravity on the atmospheric structure from L to T spectral types.

Context. eta Tel is an 18 Myr system composed of a 2.09 M-circle dot A-type star with an M7-M8 brown dwarf companion, eta Tel B. The two objects have a projected separation of 4 ''.2 (similar to 208 au). This system has been targeted by high-contrast imaging campaigns for over 20 yr, facilitating its orbital and photometric characterization. The companion, eta Tel B, both bright and on a wide orbit, is an ideal candidate for a detailed examination of its position and the characterization of its atmosphere. Aims. To explore the orbital parameters of eta Tel B, measure its contrast, and investigate its close surroundings, we analyzed three new SPHERE/IRDIS coronagraphic observations. Our objectives are to investigate the possibility of a circumplanetary disk or a close companion around eta Tel B, and characterize its orbit by combining this new data set with archival data acquired in the past two decades. Methods. The IRDIS data are reduced with state-of-the-art algorithms to achieve a contrast with respect to the star of 1.0 x 10(-5) at the location of the companion. Using the NEGative Fake Companion technique (NEGFC), we measure the astrometric positions and flux of eta Tel B for the three IRDIS epochs. Together with the measurements presented in the literature, the baseline of the astrometric follow-up is 19 yr. Results. We calculate a contrast for the companion of 6.8 magnitudes in the H band. The separation and position angle measured are 4 ''.218 and 167.3 degrees, respectively. The astrometric positions of the companions are calculated with an uncertainty of 4 milliarc-seconds (mas) in separation and 0.2 degrees in position angle. These are the smallest astrometrical uncertainties of eta Tel B obtained so far. The orbital parameters are estimated using the Orvara code, including all available epochs. The orbital analysis is performed taking into account the Gaia-HIPPARCOS acceleration of the system. Suppressing its point spread function (PSF), we have produced contrast curves centered on the brown dwarf in order to constrain our detection capabilities for a disk or companions around it. Conclusions. After considering only orbits that could not disrupt the outer debris disk around eta Tel A, our orbital analysis reveals a low eccentric orbit (e similar to 0.34) with an inclination of 81.9 degrees (nearly edge-on) and a semi-major axis of 218 au. Furthermore, we determine the mass of eta Tel B to be 48 M-Jup, consistent with previous calculations from the literature based on evolutionary models. Finally, we do not detect any significant residual pointing to the presence of a satellite or a disk around the brown dwarf. The retrieved detection limits allow us to discard massive objects around eta Tel B with masses down to 1.6 M-Jup at a separation of 33 au.

The unprecedented medium-resolution ( R λ ∼ 1500–3500) near- and mid-infrared (1–18 μ m) spectrum provided by JWST for the young (140 ± 20 Myr) low-mass (12–20 M Jup ) L–T transition (L7) companion VHS 1256 b gives access to a catalog of molecular absorptions. In this study, we present a comprehensive analysis of this data set utilizing a forward-modeling approach applying our Bayesian framework, ForMoSA . We explore five distinct atmospheric models to assess their performance in estimating key atmospheric parameters: T eff , log( g ), [M/H], C/O, γ , f sed , and R . Our findings reveal that each parameter’s estimate is significantly influenced by factors such as the wavelength range considered and the model chosen for the fit. This is attributed to systematic errors in the models and their challenges in accurately replicating the complex atmospheric structure of VHS 1256 b, notably the complexity of its clouds and dust distribution. To propagate the impact of these systematic uncertainties on our atmospheric property estimates, we introduce innovative fitting methodologies based on independent fits performed on different spectral windows. We finally derived a T eff consistent with the spectral type of the target, considering its young age, which is confirmed by our estimate of log( g ). Despite the exceptional data quality, attaining robust estimates for chemical abundances [M/H] and C/O, often employed as indicators of formation history, remains challenging. Nevertheless, the pioneering case of JWST’s data for VHS 1256 b has paved the way for future acquisitions of substellar spectra that will be systematically analyzed to directly compare the properties of these objects and correct the systematics in the models.

Aims. We aim to expand the atmospheric exploration of AF Lep b by modeling all available observations obtained with SPHERE at VLT (between 0.95-1.65, at 2.105, and 2.253 $\mu$m, and NIRC2 at Keck (at 3.8 $\mu$m) with self-consistent atmospheric models. Methods. To understand the physical properties of this exoplanet, we used ForMoSA. This forward-modeling code compares observations with grids of pre-computed synthetic atmospheric spectra using Bayesian inference methods. We used Exo-REM, an atmospheric radiative-convective equilibrium model, including the effects of non-equilibrium processes and clouds. Results. From the atmospheric modeling we derive solutions at a low effective temperature of ~750 K. Our analysis also favors a metal-rich atmosphere (>0.4) and solar to super-solar carbon-to-oxygen ratio (~0.6). We tested the robustness of the estimated values for each parameter by cross-validating our models using the leave-one-out strategy, where all points are used iteratively as validation points. Our results indicate that the photometry point at 3.8 $\mu$m strongly drives the metal-rich and super-solar carbon-to-oxygen solutions. Conclusions. Our atmospheric forward-modeling analysis strongly supports the planetary nature of AF Lep b. Its spectral energy distribution is consistent with that of a young, cold, early-T super-Jovian planet. We recover physically consistent solutions for the surface gravity and radius, which allows us to reconcile atmospheric forward modeling with evolutionary models, in agreement with the previously published complementary analysis done by retrievals. Finally, we identified that future data at longer wavelengths are mandatory before concluding about the metal-rich nature of AF Lep b.

We present a performance analysis for the aperture masking interferometry (AMI) mode on board the James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables, AMI accesses inner working angles down to and even within the classical diffraction limit. The scientific potential of this mode has recently been demonstrated by the Early Release Science (ERS) 1386 program with a deep search for close-in companions in the HIP 65426 exoplanetary system. As part of ERS 1386, we use the same data set to explore the random, static, and calibration errors of NIRISS AMI observables. We compare the observed noise properties and achievable contrast to theoretical predictions. We explore possible sources of calibration errors and show that differences in charge migration between the observations of HIP 65426 and point-spread function calibration stars can account for the achieved contrast curves. Lastly, we use self-calibration tests to demonstrate that with adequate calibration NIRISS F380M AMI can reach contrast levels of ∼9–10 mag at ≳ λ / D . These tests lead us to observation planning recommendations and strongly motivate future studies aimed at producing sophisticated calibration strategies taking these systematic effects into account. This will unlock the unprecedented capabilities of JWST/NIRISS AMI, with sensitivity to significantly colder, lower-mass exoplanets than lower-contrast ground-based AMI setups, at orbital separations inaccessible to JWST coronagraphy.

Context. Emission lines that are indicative of active accretion have been observed for a number of low-mass companions ( M < 30 M Jup ) to stars. Line variability is ubiquitous on stellar accretors, but it has never been characterized in detail for low-mass companions. Such characterizations can offer insights into the accretion mechanism at play. Aims. We aim to characterize the short-to-long-term H I Paschen β emission line variability of two 10 to 30 M Jup companions on wide orbits: GQ Lup b and GSC 06214-00210 b. We also aim to clarify their accretion mechanisms. Methods. We used J-band observations at R = 1800–2360, obtained with VLT/SINFONI in 2017, to record time-series investigations of the hours-to-weeks variability of the H I Paschen β emission line (1.282 µm). Contrary to H ∝ , it should be less affected by chromospheric activity contamination. The photospheric emission was analyzed at each epoch and removed with the ForMoSA forward-modeling tool, using new grids of ATMO models exploring different C/O and [M/H] values. The time series of line profiles and intensities were compared to those of more massive accretors and to predictions from the latest magnetospheric accretion and shock models. To complement these results, we also re-investigated archival spectroscopic observations at near-infrared wavelengths of each target to increase the time frame up to a decade and to build a more comprehensive understanding of the variability processes at play. Results. For GQ Lup b, we find line variability on timescales of several months to decades, whereas it is within the acceptable noise levels on shorter timescales. For GSC 06214-00210 b, we find line variability on timescales of tens of minutes all the way up to a decade. The line profiles of GSC 06214-00210 b are partially resolved in at least one epoch. Both objects show H I Paschen β flux variability that is moderate (<50%), on timescales that are below their rotation period, and that is more significant on longer timescales (up to ~1000% on decade-long timescales). This behavior resembles that of classical T Tauri stars. The line profiles of GQ Lup b are blue-shifted and can only be reproduced by magnetospheric accretion models, while those of GSC 06214-00210 b are fairly well reproduced by both magnetospheric accretion and shock models, except for one epoch for which the shock model is highly favored. The companions have C/O values broadly consistent with solar values. Conclusions. While magnetospheric accretion is favored for GQ Lup b, higher resolution (R > 10 000) observations are required to disentangle the two (non-exclusive) emitting mechanisms. The similar variability behavior observed in these low mass companions and in classical T Tauri stars may support similar accretion mechanisms. The high amplitude of variability on timescales of over a month and longer that is found for both objects could be key to explaining the low yield of H ∝ imaging campaigns.

Emission lines indicative of active accretion have been seen on a handful of low-mass companions (M < 30 MJup) to stars. Line variability is ubiquitous on stellar accretors but has never been characterized in detail on low-mass companions and can give insights on the accretion mechanism at play. We investigate the emission line variability of two low-mass companions (M<30 MJup) to stars to understand their accretion mechanisms. Using J-band observations, we analyze the short to long-term variability of the HI Paschen {\beta} emission line (1.282 {\mu}m) for GQ Lup b and GSC 06214-00210 b. Archival spectroscopic observations are also examined to extend the time span. We compare their line profiles and intensities to more massive accretors and magnetospheric accretion and shock models. Both objects have HI Paschen {\beta} flux variability that is moderate at short timescales (< 50 %) and increases at longer timescales (~1000 % on decade timescales), resembling classical T Tauri stars. GQ Lup b's line profiles are compatible with magnetospheric accretion. GSC 06214-00210 b's profiles are reproduced by both magnetospheric accretion and shock models, except for the brightest epoch for which the shock model is highly favored. Both companions have C/O values broadly consistent with solar values. While magnetospheric accretion is favored for GQ Lup b, higher resolution (R > 10000) observations are required to disentangle the two (non-exclusive) line formation mechanisms. The similarity in variability behavior may support similar accretion mechanisms between these low-mass companions and classical T Tauri stars. The significant variability observed at months and longer timescales could explain the low yield of H{\alpha} imaging campaigns.

We present simultaneous 0.65-2.5 microns medium resolution (3300 < R < 8100) VLT/X-Shooter spectra of the young low-mass (19+/-5MJup) L-T transition object VHS 1256-1257 b, a known spectroscopic analogue of HR8799d. The companion is a prime target for the JWST Early Release Science (ERS) and one of the highest-amplitude variable brown-dwarf known to date. We compare the spectrum to the custom grids of cloudless ATMO models exploring different atmospheric composition with the Bayesian inference tool ForMoSA. We also re-analyze low-resolution HST/WFC3 1.10-1.67 microns spectra at minimum and maximum variability to contextualize the X-Shooter data interpretation. The models reproduce the slope and most molecular absorption from 1.10 to 2.48 microns self-consistently but fail to provide a radius consistent with evolutionary model predictions. They do not reproduce consistently the optical spectrum and the depth of the K I doublets in the J-band. We derive Teff = 1380+/-54 K, log(g) = 3.97+/-0.48 dex, [M/H] = 0.21+/-0.29, and C/O > 0.63. Our inversion of the HST/WFC3 spectra suggests a relative change of 27+6-5 K of the disk-integrated Teff correlated with the near-infrared brightness. Our data anchor the characterization of that object in the near-infrared and could be used jointly to the ERS mid-infrared data to provide the most detailed characterization of an ultracool dwarf to date.

We present JWST Early Release Science coronagraphic observations of the super-Jupiter exoplanet, HIP 65426b, with the Near-Infrared Camera (NIRCam) from 2 to 5 μ m, and with the Mid-Infrared Instrument (MIRI) from 11 to 16 μ m. At a separation of ∼0.″82 (87 − 31 + 108 au), HIP 65426b is clearly detected in all seven of our observational filters, representing the first images of an exoplanet to be obtained by JWST, and the first-ever direct detection of an exoplanet beyond 5 μ m. These observations demonstrate that JWST is exceeding its nominal predicted performance by up to a factor of 10, depending on separation and subtraction method, with measured 5 σ contrast limits of ∼1 × 10 −5 and ∼2 × 10 −4 at 1″ for NIRCam at 4.4 μ m and MIRI at 11.3 μ m, respectively. These contrast limits provide sensitivity to sub-Jupiter companions with masses as low as 0.3 M Jup beyond separations of ∼100 au. Together with existing ground-based near-infrared data, the JWST photometry are fit well by a BT-SETTL atmospheric model from 1 to 16 μ m, and they span ∼97% of HIP 65426b's luminous range. Independent of the choice of model atmosphere, we measure an empirical bolometric luminosity that is tightly constrained between log L bol / L ⊙ = −4.31 and −4.14, which in turn provides a robust mass constraint of 7.1 ± 1.2 M Jup . In totality, these observations confirm that JWST presents a powerful and exciting opportunity to characterize the population of exoplanets amenable to high-contrast imaging in greater detail.

The unprecedented medium-resolution (R 1500-3500) near- and mid-infrared (1-18um) spectrum provided by JWST for the young (140+/-20Myr) low-mass (12-20MJup) L-T transition (L7) companion VHS1256b gives access to a catalogue of molecular absorptions. In this study, we present a comprehensive analysis of this dataset utilizing a forward modelling approach, applying our Bayesian framework, ForMoSA. We explore five distinct atmospheric models to assess their performance in estimating key atmospheric parameters: Teff, log(g), [M/H], C/O, gamma, fsed, and R. Our findings reveal that each parameter's estimate is significantly influenced by factors such as the wavelength range considered and the model chosen for the fit. This is attributed to systematic errors in the models and their challenges in accurately replicating the complex atmospheric structure of VHS1256b, notably the complexity of its clouds and dust distribution. To propagate the impact of these systematic uncertainties on our atmospheric property estimates, we introduce innovative fitting methodologies based on independent fits performed on different spectral windows. We finally derived a Teff consistent with the spectral type of the target, considering its young age, which is confirmed by our estimate of log(g). Despite the exceptional data quality, attaining robust estimates for chemical abundances [M/H] and C/O, often employed as indicators of formation history, remains challenging. Nevertheless, the pioneering case of JWST's data for VHS1256b has paved the way for future acquisitions of substellar spectra that will be systematically analyzed to directly compare the properties of these objects and correct the systematics in the models.

We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a <20 M Jup widely separated (∼8″, a = 150 au), young, planetary-mass companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color–magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256 b with JWST's NIRSpec IFU and MIRI MRS modes for coverage from 1 to 20 μm at resolutions of ∼1000–3700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are observed in several portions of the JWST spectrum based on comparisons from template brown dwarf spectra, molecular opacities, and atmospheric models. The spectral shape of VHS 1256 b is influenced by disequilibrium chemistry and clouds. We directly detect silicate clouds, the first such detection reported for a planetary-mass companion.

Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In this paper, we present new VLTI/GRAVITY astrometric data of HIP 65426 b, a cold, giant exoplanet which is a particular challenge for most formation theories at a projected separation of 92 au from its primary. Leveraging GRAVITY's astrometric precision, we present an updated eccentricity posterior that disfavors large eccentricities. The eccentricity posterior is still prior dependent, and we extensively interpret and discuss the limits of the posterior constraints presented here. We also perform updated spectral comparisons with self-consistent forward-modeled spectra, finding a best-fit ExoREM model with solar metallicity and C/O = 0.6. An important caveat is that it is difficult to estimate robust errors on these values, which are subject to interpolation errors as well as potentially missing model physics. Taken together, the orbital and atmospheric constraints paint a preliminary picture of formation inconsistent with scattering after disk dispersal. Further work is needed to validate this interpretation. Analysis code used to perform this work is available on GitHub: https://github.com/sblunt/hip65426.

We aim to revisit the system AB Pic which has a known companion at the exoplanet/ brown-dwarf boundary. We based this study on a rich set of observations to investigate the companion's orbit and atmosphere. We composed a spectrum of AB Pic b merging archival VLT/SINFONI K-band data, with published spectra at J and H-band (SINFONI) and Lp-band (Magellan-AO), and photometric measurements (HST and Spitzer). We modeled the spectrum with ForMoSA, based on two atmospheric models: ExoREM and BT-SETTL13. We determined the orbital properties of b fitting the astrometric measurements from NaCo (2003 and 2004) and SPHERE (2015). The orbital solutions favor a semi-major axis of $\sim$190au viewed edge-on. With Exo-REM, we derive a T$_{eff}$ of 1700$\pm$50K and surface gravity of 4.5$\pm$0.3dex, consistent with previous works, and we report for the first time a C/O ratio of 0.58$\pm$0.08 ($\sim$solar). The posteriors are sensitive to the wavelength interval and the family of models used. Given the 2.1hr rotation period and our vsin(i) of $\sim$73km/s, we estimate for the first time the true obliquity to be $\sim$45 or $\sim$135deg, indicating a significant misalignment between the planet's spin and orbit orientations. Finally, a proper motion anomaly between the Hipparcos and Gaia eDR3 compared to our SPHERE detection limits and adapted radial velocity limits indicate the existence of a $\sim$6M$_{Jup}$ inner planet orbiting from 2 to 10au (40-200mas). The possible existence of an inner companion and the likely miss-alignment of the spin axis orientation strongly favor a formation path by gravitational instability or core accretion within a disk closer inside followed by dynamical interactions. Confirmation and characterization of planet c and access to a broader wavelength coverage for planet b will be essential to probe the uncertainties associated with the parameters.

The grid of precomputed synthetic spectra of planetary atmosphere Exo-REM (Charnay et al. 2018) in the xarray format. This format is used in the forward modeling code ForMoSA (https://github.com/exoAtmospheres/ForMoSA, Petrus et al. 2020, 2021, 2023). This grid explores the parameters: Teff = 400 - 2000 log(g) = 3.0 - 5.0 [M/H] = -0.5 - 0.5 C/O = 0.1 - 0.8

Aims . We aim to revisit the formation pathway of AB Pic b, an imaged companion that straddles the exoplanet/brown-dwarf boundary. We based this study on a rich set of observations, which allows us to investigate its orbital and atmospheric properties. Methods . We composed a spectrum of AB Pic b by merging archival medium-resolution (~4000) VLT/SINFONI K band (1.96–2.45 µm) data with published spectra at J and H bands from SINFONI, Lp band from Magellan-AO/CLIO2, and photometric measurements from HST (visible) and Spitzer (mid-infrared). We modeled the spectrum with ForMoSA, following a forward-modeling approach based on two atmospheric models: ExoREM and BT-SETTL13. In parallel, we determined the orbital properties of AB Pic b fitting orbital solutions to astrometric measurements from NaCo (2003 and 2004) and SPHERE (2015). Results . The orbital solutions favor a semi-major axis of 190 -50 +200 au on a highly inclined orbit (edge-on), but with a poorly constrained eccentricity. From the atmospheric modeling with Exo-REM, we derive an effective temperature of 1700 ± 50 K and surface gravity of 4.5 ± 0.3 dex, which are consistent with previous findings, and we report for the first time a c/o ratio of 0.58 ± 0.08, consistent with the value for the Sun. The posteriors are sensitive to the wavelength interval and the family of models used. Given the published rotation period of 2.1 h and our derived υ sin( i ) of 73 -27 +11 km s −1 , we estimate for the first time the true obliquity of AB Pic b to be between 45 and 135 deg, indicating a rather significant misalignment between the spin and orbit orientations of the planet. Finally, the existence of a proper-motion anomaly between the H IPPARCOS and Gaia Early Data Release 3 compared to our SPHERE detection limits and adapted radial velocity limits indicates the potential existence of a ~6 M Jup inner planet orbiting from 2 to 10 au (40–200 mas). Conclusions . The possible existence of an inner companion and the likely misalignment of the spin-axis orientation strongly favor a formation path by gravitational instability or core accretion within a protoplanetary disk at a smaller orbital radius followed by a dynamical interaction which scattered AB Pic b to its current location. Confirmation and characterization of this unseen inner exoplanet and access to a broader wavelength coverage and higher spectral resolution for the characterization of AB Picb will be essential for probing the uncertainties associated with the atmospheric and orbital parameters.

We present the multiple stellar systems observed within the SpHere INfrared survey for Exoplanet (SHINE). SHINE searched for sub-stellar companions to young stars using high contrast imaging. Although stars with known stellar companions within the SPHERE field of view (< 5.5 arcsec) were removed from the original target list, we detected additional stellar companions to 78 of the 463 SHINE targets observed so far. Twenty-seven per cent of the systems have three or more components. Given the heterogeneity of the sample in terms of observing conditions and strategy, tailored routines were used for data reduction and analysis, some of which were specifically designed for these datasets. We then combined SPHERE data with literature and archival data, TESS light curves, and Gaia parallaxes and proper motions for an accurate characterisation of the systems. Combining all data, we were able to constrain the orbits of 25 systems. We carefully assessed the completeness of our sample for separations between 50–500 mas (corresponding to periods of a few years to a few decades), taking into account the initial selection biases and recovering part of the systems excluded from the original list due to their multiplicity. This allowed us to compare the binary frequency for our sample with previous studies and highlight interesting trends in the mass ratio and period distribution. We also found that, when such an estimate was possible, the values of the masses derived from dynamical arguments were in good agreement with the model predictions. Stellar and orbital spins appear fairly well aligned for the 12 stars that have enough data, which favours a disk fragmentation origin. Our results highlight the importance of combining different techniques when tackling complex problems such as the formation of binaries and show how large samples can be useful for more than one purpose.

The direct characterization of exoplanetary systems with high-contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, in order to maximize the scientific output over the lifetime of the mission, an exquisite understanding of the instrumental performance of JWST is needed as early in the mission as possible. In this paper, we describe our 55 hr Early Release Science Program that will utilize all four JWST instruments to extend the characterization of planetary-mass companions to ∼15 μm as well as image a circumstellar disk in the mid-infrared with unprecedented sensitivity. Our program will also assess the performance of the observatory in the key modes expected to be commonly used for exoplanet direct imaging and spectroscopy, optimize data calibration and processing, and generate representative data sets that will enable a broad user base to effectively plan for general observing programs in future Cycles.

Context.HD 95086 is a young nearby Solar System analog hosting a giant exoplanet orbiting at 57 au from the star between an inner and outer debris belt. The existence of additional planets has been suggested as the mechanism that maintains the broad cavity between the two belts.Aims.We present a dedicated monitoring of HD 95086 with the VLT/SPHERE instrument to refine the orbital and atmospheric properties of HD 95086 b, and to search for additional planets in this system.Methods.SPHERE observations, spread over ten epochs from 2015 to 2019 and including five new datasets, were used. Combined with archival observations, from VLT/NaCo (2012-2013) and Gemini/GPI (2013-2016), the extended set of astrometric measurements allowed us to refine the orbital properties of HD 95086 b. We also investigated the spectral properties and the presence of a circumplanetary disk around HD 95086 b by using the special fitting tool exploring the diversity of several atmospheric models. In addition, we improved our detection limits in order to search for a putative planet c via the K-Stacker algorithm.Results.We extracted for the first time the JH low-resolution spectrum of HD 95086 b by stacking the six best epochs, and confirm its very red spectral energy distribution. Combined with additional datasets from GPI and NaCo, our analysis indicates that this very red color can be explained by the presence of a circumplanetary disk around planet b, with a range of high-temperature solutions (1400–1600 K) and significant extinction (Av≳ 10 mag), or by a super-solar metallicity atmosphere with lower temperatures (800–300 K), and small to medium amount of extinction (Av≲ 10 mag). We do not find any robust candidates for planet c, but give updated constraints on its potential mass and location.