The dust observed in debris disks is the result of a collisional cascade initiated from ∼ km-sized parent bodies. Using near-infrared to sub-millimeter observations, we can probe particle sizes spanning 2-3 orders of magnitude, and with sufficient angular resolution we can follow the dynamics of these dust particles. Observations taken as part of the ALMA ARKS program allowed for a detailed comparison with near-infrared scattered light observations, at unprecedented resolution. The comparison between the two wavelength regimes reveals that for most gas-bearing debris disks, the distribution of small dust grains peaks outward of the distribution of large dust grains. In this paper we investigate whether gas-dust interactions can explain such radial offsets. We perform numerical simulations and compute surface brightness profiles at several wavelengths to assess which parameters drive these radial offsets. We find that while larger gas masses lead to more efficient outward radial drift, the resulting radial offset strongly depends on the optical depth of the disk, as the drift efficiency directly competes with the particles' collisional lifetime. We also find that increasing the relative number of μm-sized dust grains usually yields a larger radial offset between scattered light and millimeter observations. Finally, we show that mid-infrared observations can complement near-infrared and sub-millimeter images, and we discuss the formation of secondary rings at near-infrared wavelengths. The angular resolution achieved by the ARKS program has opened a new avenue to study the dynamics of dust particles in debris disks, revealing unexpected differences between the appearance of the disks scattered light and thermal emission. We showed that gas-dust interactions can explain the observed radial offsets and provide pointers as to which parameters have the most significant impact.

Over the past decade, ALMA has uncovered a range of substructures within exoKuiper belts, pointing to a population of undetected planets. With James Webb Space Telescope (JWST)'s sensitivity, we now have the opportunity to identify these planets thought to be responsible for the observed substructures in debris discs. We present Cycle 1 JWST/MIRI 11.4 mu m coronagraphic observations of three exoKuiper belts that exhibit gaps in their radial structures: HD 92945, HD 107146, and HD 206893, to determine whether planets are responsible for carving these structures, as seen in our Solar system with the gas giants. We reduce the JWST/MIRI data using spaceklip, and introduce new routines to mitigate the Brighter-Fatter effect and persistence. We do not detect any planet candidates, and all detected objects in the field of view are consistent with background stars or galaxies. However, by combining JWST mass limits, archival observational constraints, and astrometric accelerations, we rule out a significant portion of planet parameter space, placing tight constraints on the planets possibly responsible for these gaps. To interpret these results, we explore multiple gap-carving scenarios in discs, either massless or with non-zero mass, including clearing by in situ planet(s), as well as shaping by inner planets through mean-motion or secular apsidal resonances. Finally, we conclude that the planets causing the proper-motion anomaly in these systems must reside within the inner 20 au.

Context. Detecting light reflected off the dayside of an exoplanet in high-resolution spectroscopic data has proved to be a notoriously difficult endeavour. Despite several attempts, the faint signal has yet to be detected. Aims. We present a new effort at finding reflection signatures and show how a strong rotational broadening of the reflected spectrum can complicate this objective. Methods. We introduce a new figure of merit that quantifies the favourability of different systems for a reflection study, the reflection spectroscopy metric. Applying this metric, we identify the KELT-9 system, which features a highly misaligned, rapidly rotating host star, as the target for a case study based on a spectroscopic time series obtained by CARMENES. We also perform an injection-recovery test to determine the detectability of the signal in our data and demonstrate its sensitivity to rotational line broadening. Results. The search for a genuine reflection signal in our data resulted in a non-detection. The injection-recovery test puts this finding into context by revealing the critical importance of taking rotational broadening into account when dealing with systems featuring rapidly rotating stars and large spin-orbit misalignments. Conclusions. The case study presented here underscores the need to incorporate stellar rotation and spin-orbit misalignment into assessments of a given planet’s favourability to reflection studies.

Aims. This study focuses on the low-mass binary 2MASS J05082729-2101444 (2M0508-21), one of the few known radio-loud members of the complex periodic variable sample. Our aim is to use very long baseline interferometry to constrain the orbit. Methods. We observed the system with the Very Long Baseline Array (VLBA) in three epochs at a frequency of 4.85 GHz, which provides an angular resolution of about 3 mas. We combined the three radio astrometric observations, 119 RVs (60 VIS and 59 NIR) obtained with the CARMENES high-resolution spectrograph over a period of 8.1 years, and a relative astrometric measurement of an archival H-band Keck NIRC adaptive optics image to fit the orbital motion of the binary system. Results. The VLBA observations resolved the binary system and show emission from both stellar components, with similar fluxdensity levels (0.34-0.67 mJy), and showing slight temporal flux variations. The emission appears quiescent, with no significant circular polarization, and with no flare events. We obtained an orbital motion fit of the binary system, which shows an eccentric orbit (e = 0.71), an orbital period of 2.19 yr, and a semimajor axis of 26.964 mas (1.3 au). Conclusions. The VLBA observations made it possible to resolve the binary system and identify both stars as radio-loud sources. The combined fit shows that 2M0508-21 is an M-dwarf binary with a total dynamical mass of 0.459 +/- 0.007 M-circle dot, assuming Gaia 's parallax. This mass is slightly higher than those estimated from the luminosity and theoretical evolutionary models. The upper limit of the circular polarization at 4.85 GHz (<10%), the persistence of the quiescent emission, and the relatively low brightness temperatures are consistent with a gyro-synchrotron or synchrotron origin of the radio emission. Further VLBA observations are needed to obtain the individual masses of the stars, as well as to verify Gaia 's parallax of the system. A complete characterization of the system will help improve evolutionary models for young objects at the substellar boundary.

Stellar rotation is closely linked to both the age and the magnetic activity of stars. Through gyrochronology, studying stellar rotation provides a means to estimate stellar ages and trace the evolution of planetary systems, and it is also a crucial means to constrain and correct stellar activity effects for robust exoplanet detection and characterisation. CARMENES is a dual-channel, high-resolution (ℛ > 80 000) spectrograph that has been highly successful in detecting exoplanets around M-dwarf stars using the radial-velocity technique, and it also enables precise measurements of the projected rotational velocity ( v sin i ) from spectral line broadening. We present an oversampled convolution method that incorporates a realistic limb-darkening model to determine v sin i from CARMENES spectra by comparing observed spectra with that of a template star. The advantages over existing methods in the literature have been assessed using high-resolution synthetic spectrat that span effective temperatures of 2500–4000 K and projected rotational velocities of up to 50 km s −1 . We applied our method to 392 M dwarfs observed with CARMENES and it yielded v sin i measurements (or upper limits at 2 km s −1 ) with a median relative uncertainty of 6.8%, which is substantially smaller than the 15.4% reported in the literature. This work provides the largest uniform catalogue of v sin i measurements for M dwarfs, including significantly updated values for several targets, along with 36 new targets.

Context. The dust observed in debris disks is the result of a collisional cascade initiated from approximately kilometer-sized parent bodies. Using near-infrared to submillimeter observations, we can probe particle sizes spanning 2-3 orders of magnitude, and with sufficient angular resolution we can follow the dynamics of these dust particles. Observations taken as part of the ALMA survey to Resolve exoKuiper belt Substructures (ARKS) program allowed for a detailed comparison with near-infrared scattered light observations, at an unprecedented resolution. Aims. The comparison between the two wavelength regimes reveals that for most gas-bearing debris disks, the distribution of small dust grains peaks outside the distribution of large dust grains. In this paper, we investigate whether gas-dust interactions can explain such radial offsets. Methods. We performed numerical simulations that account for the effects of radiation pressure, gas drag, and collisions, and computed surface brightness profiles at several wavelengths to assess which parameters drive these radial offsets. We explored several families of models, varying the gas mass, disk optical depth, dust size distribution, and radiation pressure strength. Results. We find that while higher gas masses lead to more efficient outward radial drift, the resulting radial offset strongly depends on the optical depth of the disk, as the drift efficiency directly competes with the particles’ collisional lifetime. We also find that increasing the relative number of micron-sized dust grains usually yields a larger radial offset between scattered light and millimeter observations. Finally, we show that mid-infrared observations can complement near-infrared and submillimeter images, and we discuss the formation of secondary rings at near-infrared wavelengths. Conclusions. The angular resolution achieved by the ARKS program has opened a new avenue for studying the dynamics of dust particles in debris disks, revealing unexpected differences between the appearance of the disks scattered light and thermal emission. We show that gas-dust interactions can explain the observed radial offsets and provide pointers as to which parameters have the most significant impact.

Stellar rotation is closely linked to both the age and the magnetic activity of stars. Through gyrochronology, studying stellar rotation provides a means to estimate stellar ages and trace the evolution of planetary systems, and it is also a crucial means to constrain and correct stellar activity effects for robust exoplanet detection and characterisation. CARMENES is a dual-channel, high-resolution (R > 80000) spectrograph that has been highly successful in detecting exoplanets around M-dwarf stars using the radial-velocity technique, and it also enables precise measurements of the projected rotational velocity (u sin i) from spectral line broadening. We present an oversampled convolution method that incorporates a realistic limb-darkening model to determine u sin i from CARMENES spectra by comparing observed spectra with that of a template star. The advantages over existing methods in the literature have been assessed using high-resolution synthetic spectra that span effective temperatures of 2500-4000 K and projected rotational velocities of up to 50 km s(-1). We applied our method to 392 M dwarfs observed with CARMENES and it yielded u sin i measurements (or upper limits at 2 km s(-1)) with a median relative uncertainty of 6.8%, which is substantially smaller than the 15.4% reported in the literature. This work provides the largest uniform catalogue of u sin i measurements for M dwarfs, including significantly updated values for several targets, along with 36 new targets.

Context. With no conclusive detection to date, the search for exomoons, satellites of planets orbiting other stars, remains a formidable challenge. Detecting these objects, compiling a population-level sample and constraining their occurrence will inform planet and moon formation models and shed light on moon habitability. Aims. Here, we demonstrate the possibility of a moon search based on astrometric time series data, repeated measurements of the position of a given planet relative to its host star. The perturbing influence of an orbiting moon induces a potentially detectable planetary reflex motion. Methods. Based on an analytical description of the astrometric signal amplitude, we placed the expected signatures of putative moons around real exoplanets into context with our current and future astrometric measurement precision. Modelling the orbital perturbation as a function of time, we then simulated the detection process given different target system configurations, instrumental measurement precisions and numbers of observational epochs to obtain the first astrometric exomoon sensitivity curves. Results. The astrometric technique already allows for the detection and characterisation of favourable moons around giant exoplanets and brown dwarfs. Since the detection sensitivity of this method is mainly governed by the achievable astrometric precision, long-baseline interferometry lends itself ideally to this pursuit. We find that, on the basis of 12 epochs obtained with VLTI/GRAVITY, it is already today possible to infer at a confidence of 5 σ the presence of a 0.14 MJup satellite at a separation of 0.39 AU around AF Lep b. Future facilities offering better precision will refine our sensitivity in both moon mass and separation from the host planet by several orders of magnitude. Conclusions. The astrometric method of exomoon detection, especially when applied to interferometric observations, provides a promising avenue towards making the detection of these elusive worlds a reality and efficiently building a sample of confirmed objects. With a future facility that achieves an astrometric precision of 1 μas, probing for Earth-like moons within the habitable zone of a given star will become a realistic proposition.

Context. Transmission spectra of Neptune-sized exoplanets are frequently observed to be featureless at low-to-mid resolutions from space; whereas high-altitude clouds can mute spectral features, high atmospheric metallicities can also result in compressed envelopes, where low scale heights may also yield undetectable signatures. Aims. We aim to study the atmospheric properties of the warm Neptune GJ 436 b by combining a set of five transit events observed with the CARMENES spectrograph with one transit from CRIRES+ so as to provide the most constrained results possible at high resolution. Methods. We removed telluric and stellar signals from the data using SysRem and potential planetary signals were investigated using the cross-correlation technique. Following standard procedures for undetected species, we performed injection recovery tests and Bayesian retrievals to place constraints on the detectability of the main near-infrared absorbers. In addition, we simulated ELT/ANDES observations by computing end-to-end in silico datasets with EXoPLORE. Results. No molecular signals were detected in the atmosphere of GJ 436 b, which is consistent with previous studies. Combined CARMENES-CRIRES+ injection-recovery and Bayesian retrieval analyses show that the atmosphere is likely covered by high-altitude clouds (~1 mbar) at low and intermediate metallicities or, alternatively, is very metal-rich (≳ 900× solar), which would suppress spectral features without invoking clouds. Simulations of ELT/ANDES observations suggest a boost by nearly an order of magnitude to the upper limit in the photon-limited regime, reaching 0.1 mbar at 10-300× solar metallicities. Conclusions. The joint analysis of all useful transit observations from CARMENES and CRIRES+ provides the most stringent constraints to date on the atmospheric properties of GJ 436 b. Complementary CCF-based and retrieval approaches consistently indicate that the atmosphere is either cloudy or highly metal enriched. Any weak near-infrared absorption lines, if present, are likely to be below current detection limits. However, according to our simulations, these features may be revealed with ELT/ANDES even in single-transit observations.

Context: Although there has been significant progress, the physical properties and potential fragmentation of accretion disks around high-mass protostars remain poorly constrained. Aims: We characterize at high angular resolution one of the most nearby ( 700pc) high-mass accretion disk candidates CepA HW2. Methods: Using the new long baseline array configuration ( 1700m) of the Northern Extended Millimeter Array (NOEMA), we study CepA HW2 with a resolution of <=0.2” or <=100au at 1.3mm in dust continuum and spectral line emission. Results: The mm continuum emission resolves the central disk candidate into several sub-structures. Conducting a Toomre Q stability analysis based on CH_3CN and continuum data, and a comparison to 3D radiation hydrodynamic simulations shows that the data are consistent with an almost edge-on disk where the observed sub-structures may represent fragments within the disk. The CO and SiO spectral line data confirm a second bipolar outflow (in addition to the well-known jet) emanating from the central peak position. This indicates that this central peak should host at least a binary if not even a higher order multiple system. The usually assumed dense gas tracer CH_3CN shows also contributions from the outflows which complicates further kinematic analysis of the disk. Conclusions: The high-resolution outflow-disk data of CepA reveal a multiply fragmented disk that drives several outflows. These observations enforce the picture of high-mass star formation where multiplicity and fragmentation can happen on the smallest spatial scales related to the inner accretion disks.

Context. The base of protostellar outflows can display both wide-angle, low-velocity winds and high-velocity, collimated jets, the magnetocentrifugal launching of which enables accretion onto the protostar. In outflows from the youngest protostars, the majority of the ejected or entrained mass is likely molecular H2 . How the H2 outflow evolves as the central protostar grows and the envelope dissipates is important for understanding the nature of the launching mechanism and assembly of the nascent protostar. Aims. Using JWST MIRI/MRS observations with an unprecedented spatial resolution down to 0.3" towards 13 single and 20 multiple Class 0 and I protostars, we aim to investigate the H2 wind and jet morphology, mass outflow rate, velocity and temperature structure, and the evolution of these properties with protostellar class. Methods. We constructed continuum-subtracted maps of the H2 S(1) and S(7) line flux and velocity towards the outflows in our sample and ALMA sub-millimetre CO maps. Towards the base of each blueshifted outflow lobe (typically within 300 au), we extracted representative spectra and measured the outflow opening angles from the H2 S(1) line emission. A rotation-diagram fitting of the H2 lines was used to determine the column density and temperature, which was combined with measurements of the outflow width and H2 line velocity to measure the mass-loss rates. Results. Low- J (J ≤ 4) transitions of H2 largely trace extended wide-angle, low-velocity (0-20 km s−1) winds within the contours of the low-velocity (<30 km s−1) sub-millimetre CO emission, while high-J (J > 5) transitions are associated with shocks and knots. In Class 0 sources with a known high-velocity (>30 km s−1) molecular CO or SiO jet, higher H2 velocities are observed along the jet axis. The opening angle of the wind traced by the H2 S(1) line broadens from ∼20° to ∼90° through the Class 0 to the Class I stage. The rotation diagrams in the blueshifted outflow lobes show a clear separation between a warm, ∼600 K and a hot, 1500-3000 K component, with no clear sign of evolution in the excitation temperature. The warm component contains two orders of magnitude more mass than the hot component, and the H2 outflow mass-loss rate declines by two orders of magnitude from the Class 0 to the Class II stage. A correlation with the bolometric luminosity of the driving source is observed. A factor of 10–1000 mismatch between the warm H2 and cold sub-millimetre CO outflow rate and momentum flux is also seen, which is consistent with the presence of cold and likely entrained (<150 K) molecular H2 that cannot be detected with JWST/MIRI. Conclusions. The declining warm H2 mass-loss rates and increasing opening angles from the Class 0 to I stages – and the absence of H2 jets in the Class I sources – are consistent with the predictions of magnetohydrodynamical (MHD) disc wind models; however, the relatively constant temperatures of the warm and hot components with evolutionary stage may reflect the typical conditions in the outflow shocks rather than temperature stratification of the wind.

Context. Debris discs are analogues to our own Kuiper belt around main-sequence stars and are therefore referred to as exoKuiper belts. They have been resolved at high angular resolution at wavelengths spanning the optical/near-infrared to the submillimetre-millimetre regime. Short wavelengths can probe the light scattered by such discs, which is dominated by micron-sized dust particles, while millimetre wavelengths can probe the thermal emission of millimetre-sized particles. Determining differences in the dust distribution between millimetre- and micron-sized dust is fundamental to revealing the dynamical processes affecting the dust in debris discs. Aims. We aim to compare the scattered light from the discs of the 'ALMA survey to Resolve exoKuiper belt Substructures' (ARKS) with the thermal emission probed by ALMA. We focus on the radial distribution of the dust, and we also put constraints on the presence of giant planets in those systems. Methods. We used high-contrast scattered light observations obtained with VLT/SPHERE, GPI, and the HST to uniformly study the dust distribution in those systems and compare it to the dust distribution extracted from the ALMA observations carried out in the course of the ARKS project. We also set constraints on the presence of planets by using these high-contrast images combined with exoplanet evolutionary models. Results. Fifteen of the 24 discs comprising the ARKS sample are detected in scattered light, with TYC 9340-437-1 being imaged for the first time at near-infrared wavelengths. For six of those 15 discs, the dust surface density seen in scattered light peaks farther out compared to that observed with ALMA. These six discs except one are known to also host cold CO gas. Conversely, the systems without significant offsets are not known to host gas, except one. Moreover, with our scattered light near-infrared images, we achieve typical sensitivities to planets from 1 to 10 M-Jup beyond 10 to 20 au, depending on the system age and distance. Conclusions. This observational study suggests that the presence of gas in debris discs may affect the small and large grains differently, pushing the small dust to greater distances where the gas is less abundant.

Context. Direct observations of exoplanet and brown dwarf companions with near-infrared interferometry, first enabled by the dualfield mode of VLTI/GRAVITY, provide unique measurements of the objects' orbital motions and atmospheric compositions. Aims. Here we compile a homogeneous library of all exoplanet and brown dwarf K-band spectra observed by GRAVITY thus far. This ExoGRAVITY Spectral Library is made publicly available online. Methods. We re-reduced all the available GRAVITY dual-field high-contrast data in a uniform and highly automated way and, where companions were detected, extracted their similar to 2.0-2.4 mu m K-band contrast spectra. We then derived stellar model atmospheres for all the employed flux references (either the host star or the swap calibrator), which we used to convert the companion contrast into companion flux spectra. Solely from the resulting GRAVITY K-band flux spectra, we extracted spectral types, spectral indices, and bulk physical properties for all the companions. Finally, and with the help of age constraints from the literature, we also derived isochronal masses for most of the companions using evolutionary models. Results. The resulting library contains R similar to 500 GRAVITY K-band spectra of 39 substellar companions from late M to late T spectral types, including the entire L-T transition. Throughout this transition, a shift from CO-dominated late M- and L-type dwarfs to CH4-dominated T-type dwarfs can be observed in the K-band. The GRAVITY spectra alone constrain the objects' bolometric luminosity to typically within +/- 0.15 dex. The derived isochronal masses agree with dynamical masses from the literature where available, except for HD 4113 c for which we confirm its previously reported potential underluminosity. Conclusions. Medium-resolution spectroscopy of substellar companions with GRAVITY provides insight into the carbon chemistry and the cloudiness of these objects' atmospheres. It also constrains these objects' bolometric luminosities, which can yield measurements of their formation entropy if combined with dynamical masses, for instance from Gaia and GRAVITY astrometry.

Context. Silicates are key constituents of planet-forming disks and are among the most important building blocks of rocky planets. Mid-infrared spectral features of micron-sized silicate grains are powerful tracers of grain growth, mineralogy, and disk chemistry. Aims. We characterized the dust mineralogy in T Tauri disks using James Webb Space Telescope (JWST)/Mid-Infrared Instrument (MIRI) observations. A further aim of ours was to investigate the connections between the dust and molecular gas compositions. Methods. We analyzed JWST/MIRI spectra of 26 disks as part of the MIRI mid-Infrared Disk Survey (MINDS). We employed spectral decomposition with our new DustComp tool to derive the mass fractions of individual dust species. We included in our fits Mg2SiO4 (forsterite), MgSiO3 (enstatite), and SiO2 (silica) together with amorphous silicates of corresponding stoichiometry. Results. We find that Mg-rich (and Fe-poor) silicates represent our data well. Fit residuals are typically within ±3%. Grain size distributions are skewed toward larger sizes (>2 μm), indicating significant growth. Large (~5 μm-sized) amorphous Mg-silicates were robustly detected, whereas the presence of large crystalline grains could not be firmly established. The average dust composition is dominated by grains of Mg2SiO4 stoichiometry (~60%, including amorphous and crystalline state), followed by MgSiO3 (~30%) and SiO2 (∼10%). The mass fractions of crystalline grains are typically in the 5-24% range, with a mean of 14%. We robustly detected annealed silica in nine objects, with cristobalite as the main polymorph. We found a correlation between dust and molecular gas composition: disks with strong annealed silica features show relatively strong CO2 emission, while forsterite-rich disks display stronger H2O emission. Disks with annealed silica features may also have elevated gas-phase C/O ratios, suggesting a process, such as dust sublimation and recondensation, that establishes thermo-chemical equilibrium between solids and gas. Conclusions. The correlation between dust and gas may provide the first indication that the molecular gas composition regulates the availability of dust species in the inner disk.

Context. The physical conditions and processes taking place in the innermost regions of protoplanetary disks are essential for planet formation and general disk evolution. In this context, we study the T-Tauri type young stellar object RY Tau, which exhibits a dust-depleted inner cavity characteristic of a transition disk. Aims. The goal of this study is to analyze spectrally resolved interferometric observations in the L, M, and N bands of the RY Tau protoplanetary disk obtained with MATISSE. We aim to provide constraints on the spatial distribution and mineralogy of dust in the inner few astronomical units by producing synthetic observations fitting the interferometric observables. Methods. We employed a 2D temperature gradient disk model to estimate the orientation of the inner disk. Successively, we analyzed the chemical composition of silicates depending on spatial region in the disk. Finally, we sampled the parameter space of a viscous accretion disk model via Monte Carlo radiative transfer simulations to investigate the actual 3D dust density distribution of RY Tau. Results. We constrained the orientation of the inner disk of RY Tau, finding no evidence of significant misalignment with respect to its outer disk. We identified several silicate species commonly found in protoplanetary disks and observed a depletion of amorphous dust grains toward the central protostar. By simultaneously considering the observed visibilities and the spectral energy distribution (SED), we found that an accretion disk and an optically thin envelope enshrouding the protostar fits the observations best. Radiative transfer simulations show that hot dust close to the protostar and in the line of sight (LOS) to the observer, either in the uppermost disk layers of a strongly flared disk or in a dusty envelope, is necessary to model the observations. The shadow cast by a dense innermost disk midplane on the dust further out explains the observed closure phases in the L band and (to some extent) in the M band. However, the closure phases in the N band are underestimated by our model, hinting at an additional asymmetry in the flux density distribution that is not visible at shorter wavelengths.

Ground-based high-resolution spectroscopic observations have identified various chemical species in the atmosphere of numerous ultra-hot Jupiters (UHJs), including neutral and ionized metals. These detections have offered valuable insights into planet formation mechanisms via abundance measurements of refractory elements. We observed the dayside thermal emission spectrum of UHJ HAT-P-70b using the high-resolution spectrographs CARMENES and PEPSI. Through our cross-correlation analysis, we detected emission signals for Al I, AlH, Ca II, Cr I, Fe I, Fe II, Mg I, Mn I, and Ti I, marking the first detection of Al I and AlH in an exoplanetary atmosphere. Tentative signals of C I, Ca I, Na I, NaH, and Ni i were also identified. Based on those detections, we were able to perform atmospheric retrievals to constrain the thermal profile and elemental abundances of the planet’s dayside hemisphere. The retrieved temperature-pressure profile reveals a strong temperature inversion layer. The chemical free retrieval yielded a metallicity of [Fe/H] = 0.38−1.11+0.74, while the chemical equilibrium retrieval resulted in [Fe/H] = 0.23−0.98+1.08, with both values consistent with the solar metallicity. We also tentatively found an enriched abundance of Ni, which could result from the accretion of Ni-rich planetesimals during the planet’s formation. On the other hand, elements with condensation temperatures above 1400 K(e.g., Ca, Ti, and V) appear to be slightly depleted, possibly due to cold-trapping on the planet’s nightside. However, Al, with the highest condensation temperature at 1653 K, displays a solar-like abundance, which might reflect the formation-related enrichment of Al. Our retrieval indicates extremely high volume mixing ratios of metal ions (Fe II and Ca II), which are significantly inconsistent with predictions from chemical equilibrium models. This disequilibrium suggests that the atmosphere is likely undergoing significant hydrodynamic escaping, which enhances the atmospheric density at high altitudes where the ionic lines are formed.

Context. Unbiased surveys of large stellar samples are the prime means through which the prevalence of exoplanets can be derived, and crucial constraints to planet formation models can be set. Direct imaging (DI) is ideally positioned to probe the outer regions (5-300 au) of planetary systems, providing complementary information to techniques such as transits and radial velocities. Aims. We present the full sample of the SpHere INfrared survey for Exoplanets (SHINE), the second largest DI campaign to date. SHINE observed 460 stars between 2015 and 2023 thanks to the guaranteed time observations (GTO) allocated by ESO to the SPHERE consortium at VLT. The goal of this paper is to homogeneously derive the stellar properties of the targets and to define a subsample of young single hosts to be used as a starting point for the final statistical analysis of the survey. Methods. Stellar ages were determined based on kinematic indicators (such as the membership to young moving groups), age diagnostics (lithium abundance, rotation, and activity), and isochrone fitting. A thorough vetting for binarity was undertaken combining astrometric, spectroscopic, and imaging data. Results. A subsample of 333 stars, covering a large extent of stellar ages and masses, was constructed. Selection criteria, global features, as well as the properties of individual stars are reported and discussed.

Context. This study presents the first application of high-precision astrometry to search for exomoons around substellar companions, as this field remains largely unexplored. Aims. We investigate whether the orbital motion of the companion HD 206893 B exhibits astrometric residuals consistent with the gravitational influence of an exomoon or binary planet. Methods. Using the VLTI/GRAVITY instrument, we monitored the astrometric positions of HD 206893 B and c on short (days to months) and long (yearly) timescales. This enabled us to isolate potential residual wobbles in the motion of component B attributable to an orbiting moon. Results. Our analysis reveals tentative astrometric residuals in the HD 206893 B orbit. If interpreted as an exomoon signature, these residuals correspond to a candidate (HD 206893 B I) with an orbital period of approximately 0.76 years and a mass of ~0.4 Jupiter masses. However, the origin of these residuals remains ambiguous and could be due to systematics. Complementing the astrometry, our analysis of GRAVITY R = 4000 spectroscopy for HD 206893 B confirms a clear detection of water, but no CO was found using cross-correlation. We also found that AF Lep b, and β Pic b are the best short-term candidates to look for moons with GRAVITY+. Conclusions. Our observations demonstrate the transformative potential of high-precision astrometry in the search for exomoons and proves the feasibility of the technique to detect moons with masses lower than Jupiter and potentially down to less than Neptune in optimistic cases. Crucially, further high-precision astrometric observations with VLTI/GRAVITY are essential to verify the reality and nature of this signal and apply this technique to a range of planetary systems.

We investigate two massive young stellar objects (YSOs), IRAS21078+5211 and G035.02+0.35, where evidence for magnetohydrodynamic (MHD) disk winds (DWs) has been obtained at scales of 10-100 au through measurements of the 22GHz water maser velocity distribution within the Protostellar Outflows at the EarliesT Stages (POETS) survey. We employ IRAM Northern Extended Millimeter Array and archival Atacama Large Millimeter Array observations of IRAS21078+5211 and G035.02+0.35, respectively, to study kinematics and physical conditions of the corresponding protostellar winds on scales of 100-1000 au using the same molecular tracers. In IRAS21078+5211, the emissions of several molecules, particularly SO, SO2, CH3CN and CH3OH, are distributed along the axis of the radio jet, and present a LSR velocity (Vlsr) gradient transversal to the jet axis. Position-velocity (PV) plots of the SO lines show patterns consistent with Keplerian rotation. The SO2 emission comes from high velocity gas flowing close to the jet axis, while CH3CN and CH3OH present larger radial extension than the S-bearing species. In G035.02+0.35, the same molecules are instead distributed along the major axis of the rotating disk, and their Vlsr gradients consistently trace the disk rotation. The corresponding PV plots present Keplerian profiles. SO is the only molecular species whose emission extends well outside the disk. In both YSOs, the spatial and velocity distributions of SO are consistent with a rotating wind magneto-centrifugally launched from the YSO disk. The comparison with models of molecule formation and excitation in shocks indicates that the different radial extension of the molecular species observed in the protostellar wind of IRAS21078+5211, as well as the lack of molecules, except SO, in the G035.02+0.35's wind, can be explained in terms of a radially extended MHD DW, rather than a compact X-wind.

Context. The inner regions of planet-forming disks hold invaluable insights for our understanding of planet formation. The inner disk regions that might be affected by already formed planets are of particular interest. The disk around the Herbig star HD 100453 presents one such environment, with an inner disk that is significantly misaligned with respect to the outer disk. Aims. This paper expands the existing H band (PIONIER) and K band (GRAVITY) interferometric studies of the inner disk of HD 100453 to the L band with the MATISSE VLTI instrument. Based on snapshot data spanning approximately four years, we aim to understand the inner disk structures and their potential time evolution better. Methods. Based on the MATISSE data we obtained, we used a combination of analytical models and image reconstruction to constrain the disk structure. Additionally, we fitted a temperature gradient model to the selected wavelength range of PIONIER, GRAVITY, and MATISSE to derive the physical properties of the inner regions. Results. Our parametric model determined an inclination of approximate to 47.5 degrees and a position angle of approximate to 83.6 degrees, which corroborates the strong misalignment of the inner to the outer disk. From the symmetric temperature gradient, we derive an inner disk radius of approximate to 0.27 au, with dust surface densities of Sigma(subl) approximate to 10(-3.2) g/cm(2) and a vertical optical depth tau(z,subl) approximate to 0.1-0.06. Same-night MATISSE and GRAVITY observations show directional discrepancies that are inconsistent with a first-order azimuthally modulation ring. This indicates that higher-order asymmetries are required to explain the interferometric signals. This interpretation is further supported by a MATISSE snapshot image reconstruction that revealed a two-component asymmetric structure. Conclusions. The chromatic interferometric data reveal that higher-order asymmetries are probably required to explain the inner disk of HD 100453, which suggests a possible origin in dynamic interactions or disk instabilities. Coordinated multi-wavelength infrared interferometric observations with GRAVITY and MATISSE will be crucial to confirm these findings and uncover their underlying nature.