A family portrait of disk inner rims around Herbig Ae/Be stars. Hunting for warps, rings, self shadowing, and misalignments in the inner astronomical units

Context. The innermost astronomical unit (au) in protoplanetary disks is a key region for stellar and planet formation, as exoplanet searches have shown a large occurrence of close-in planets that are located within the first au around their host star. Aims: We aim to reveal the morphology of the disk inner rim using near-infrared interferometric observations with milli-arcsecond resolution provided by near-infrared multitelescope interferometry. Methods: We provide model-independent reconstructed images of 15 objects selected from the Herbig AeBe survey carried out with PIONIER at the Very Large Telescope Interferometer, using the semi-parametric approach for image reconstruction of chromatic objects. We propose a set of methods to reconstruct and analyze the images in a consistent way. Results: We find that 40% of the systems (6/15) are centrosymmetric at the angular resolution of the observations. For the rest of the objects, we find evidence for asymmetric emission due to moderate-to-strong inclination of a disk-like structure for ~30% of the objects (5/15) and noncentrosymmetric morphology due to a nonaxisymmetric and possibly variable environment (4/15, ~27%). Among the systems with a disk-like structure, 20% (3/15) show a resolved dust-free cavity. Finally, we do not detect extended emission beyond the inner rim. Conclusions: The image reconstruction process is a powerful tool to reveal complex disk inner rim morphologies, which is complementary to the fit of geometrical models. At the angular resolution reached by near-infrared interferometric observations, most of the images are compatible with a centrally peaked emission (no cavity). For the most resolved targets, image reconstruction reveals morphologies that cannot be reproduced by generic parametric models (e.g., perturbed inner rims or complex brightness distributions). Moreover, the nonaxisymmetric disks show that the spatial resolution probed by optical interferometers makes the observations of the near-infrared emission (inside a few au) sensitive to temporal evolution with a time-scale down to a few weeks. The evidence of nonaxisymmetric emission that cannot be explained by simple inclination and radiative transfer effects requires alternative explanations, such as a warping of the inner disks. Interferometric observations can therefore be used to follow the evolution of the asymmetry of those disks at an au or sub-au scale

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

The SHINE project is a 500-star survey performed with SPHERE on the VLT 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 that are representative of the full SHINE sample. Our goal is to constrain the frequency of substellar companions with masses between 1 and 75 MJup and semimajor axes between 5 and 300 au. We adopt detection limits as a function of angular separation from the survey data for all stars converted into mass and projected orbital separation using the BEX-COND-hot evolutionary tracks and known distance to each system. Based on the results obtained for each star and on the 13 detections in the sample, we use a MCMC tool to compare our observations to two different types of models. The first is a parametric model based on observational constraints, and the second type are numerical models that combine advanced core accretion and gravitational instability planet population synthesis. Using the parametric model, we show that the frequencies of systems with at least one substellar companion are $23.0_{-9.7}^{+13.5}\%$, $5.8_{-2.8}^{+4.7}\%$, and $12.6_{-7.1}^{+12.9}\%$ for BA, FGK, and M stars, respectively. We also demonstrate that a planet-like formation pathway probably dominates the mass range from 1-75 MJup for companions around BA stars, while for M dwarfs, brown dwarf binaries dominate detections. In contrast, a combination of binary star-like and planet-like formation is required to best fit the observations for FGK stars. Using our population model and restricting our sample to FGK stars, we derive a frequency of $5.7_{-2.8}^{+3.8}\%$, consistent with predictions from the parametric model. More generally, the frequency values that we derive are in excellent agreement with values obtained in previous studies.Comment: 24 pages, 14 figures, 3 tables. Accepted for publication in A&

The SPHERE Infrared Survey for Exoplanets (SHINE): II. Observations, Data Reduction and Analysis, Detection Performances, and Initial Results

Context. In recent decades, direct imaging has confirmed the existence of substellar companions (exoplanets or brown dwarfs) on wide orbits (>10 au) around their host stars. In striving to understand their formation and evolution mechanisms, in 2015 we initiated the SPHERE infrared survey for exoplanets (SHINE), a systematic direct imaging survey of young, nearby stars that is targeted at exploring their demographics. Aims. We aim to detect and characterize the population of giant planets and brown dwarfs beyond the snow line around young, nearby stars. Combined with the survey completeness, our observations offer the opportunity to constrain the statistical properties (occurrence, mass and orbital distributions, dependency on the stellar mass) of these young giant planets. Methods. In this study, we present the observing and data analysis strategy, the ranking process of the detected candidates, and the survey performances for a subsample of 150 stars that are representative of the full SHINE sample. Observations were conducted in a homogeneous way between February 2015 and February 2017 with the dedicated ground-based VLT/SPHERE instrument equipped with the IFS integral field spectrograph and the IRDIS dual-band imager, covering a spectral range between 0.9 and 2.3 μm. We used coronographic, angular, and spectral differential imaging techniques to achieve the best detection performances for this study, down to the planetary mass regime. Results. We processed, in a uniform manner, more than 300 SHINE observations and datasets to assess the survey typical sensitivity as a function of the host star and of the observing conditions. The median detection performance reached 5σ-contrasts of 13 mag at 200 mas and 14.2 mag at 800 mas with the IFS (YJ and YJH bands), and of 11.8 mag at 200 mas, 13.1 mag at 800 mas, and 15.8 mag at 3 as with IRDIS in H band, delivering one of the deepest sensitivity surveys thus far for young, nearby stars. A total of sixteen substellar companions were imaged in this first part of SHINE: seven brown dwarf companions and ten planetary-mass companions.These include two new discoveries, HIP 65426 b and HIP 64892 B, but not the planets around PDS70 that had not been originally selected for the SHINE core sample. A total of 1483 candidates were detected, mainly in the large field of view that characterizes IRDIS. The color-magnitude diagrams, low-resolution spectrum (when available with IFS), and follow-up observations enabled us to identify the nature (background contaminant or comoving companion) of about 86% of our subsample. The remaining cases are often connected to crowded-field follow-up observations that were missing. Finally, even though SHINE was not initially designed for disk searches, we imaged twelve circumstellar disks, including three new detections around the HIP 73145, HIP 86598, and HD 106906 systems. Conclusions. Nowadays, direct imaging provides a unique opportunity to probe the outer part of exoplanetary systems beyond 10 au to explore planetary architectures, as highlighted by the discoveries of: one new exoplanet, one new brown dwarf companion, and three new debris disks during this early phase of SHINE. It also offers the opportunity to explore and revisit the physical and orbital properties of these young, giant planets and brown dwarf companions (relative position, photometry, and low-resolution spectrum in near-infrared, predicted masses, and contrast in order to search for additional companions). Finally, these results highlight the importance of finalizing the SHINE systematic observation of about 500 young, nearby stars for a full exploration of their outer part to explore the demographics of young giant planets beyond 10 au and to identify the most interesting systems for the next generation of high-contrast imagers on very large and extremely large telescopes. © M. Langlois et al. 2021.SPHERE is an instrument designed and built by a consortium consisting of IPAG (Grenoble, France), MPIA (Heidelberg, Germany), LAM (Marseille, France), LESIA (Paris, France), Laboratoire Lagrange (Nice, France), INAF – Osservatorio di Padova (Italy), Observatoire de Genève (Switzerland), ETH Zürich (Switzerland), NOVA (Netherlands), ONERA (France) and ASTRON (Netherlands) in collaboration with ESO. SPHERE was funded by ESO, with additional contributions from CNRS (France), MPIA (Germany), INAF (Italy), FINES (Switzerland) and NOVA (Netherlands). SPHERE also received funding from the European CommissionSixth and Seventh Framework Programmes as part of the Optical Infrared Coordination Network for Astronomy (OPTICON) under grant number RII3-Ct-2004-001566 for FP6 (2004-2008), grant number 226604 for FP7 (2009-2012) and grant number 312430 for FP7 (2013-2016). This paper is based on observations collected at the European Southern Observatory under ESO programmes 198.C-0209, 097.C-0865, 095.C-0298, 095.C-0309,096.C-0241. This work has made use of the SPHERE Data Centre, jointly operated by OSUG/IPAG (Grenoble), PYTHEAS/LAM/CeSAM (Marseille), OCA/Lagrange (Nice), Observatoire de Paris/LESIA (Paris), and Observatoire de Lyon (OSUL/CRAL). This work is supported by the French National Research Agency in the framework of the Investissements d’Avenir program (ANR-15-IDEX-02), through the funding of the “Origin of Life” project of the Univ. Grenoble-Alpes. This work is jointly supported by the French National Programms (PNP and PNPS) and by the Action Spécifique Haute Résolution Angulaire (ASHRA) of CNRS/INSU co-funded by CNES. We also thank the anonymous referee for her/his careful reading of the manuscript as well as her/his insightful comments and suggestions. AV acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 757561). A.-M.L. acknowledges funding from French National Research Agency (GIPSE project). C.P. acknowledges financial support from Fondecyt (grant 3190691) and financial support from the ICM (Iniciativa Científica Milenio) via the Núcleo Milenio de Formación Planetaria grant, from the Universidad de Valparaíso. T.H. acknowledges support from the European Research Council under the Horizon 2020 Framework Program via the ERC Advanced Grant Origins 832428

Quelques applications des relateurs arithmétiques : de la physique à la socio-économie (documents anciens inédits et synthèses récentes)

La première partie du rapport de recherche est constituée de trois articles , inédits auxquels le groupe Systema fait parfois référence. Le plus ancien (1987) établit une liaison entre certains relateurs arithmétiques dégénérés et des algorithmes résolvant certaines équations différentielles (cas de l'oscillateur harmonique quantique par exemple). Dans l'article suivant (1988), sont esquissées des formes de cellules cérébrales (une condition de "bifurcation" est appliquée à un relateur arithmétique biquadratique). Dans le troisième (1988), des relateurs à deux variables d'environnement sont utilisées, à un niveau de synthèse élevé, pour une modélisation de certains phénomènes de vieillissement. La deuxième partie concerne des problèmes généraux (tels que la complexité, les relations entre science et tradition) et des applications spécifiques en physique, biologie, informatique, sciences humaines, socio-économie (communications présentées en août 1992 lors du XIIIe Congrès International de Cybernétique). Les plus récentes publications exploitent la notion de 1 système générique et de 1/2 pilotage. La troisième partie est une synthèse sur les applications des relateurs arithmétiques, rédigée à l'intention des auditeurs de la deuxième Ecole de Systémique (Mont Ste Odile, octobre 1992)

Quelques applications des relateurs arithmétiques : de la physique à la socio-économie (documents anciens inédits et synthèses récentes)

La première partie du rapport de recherche est constituée de trois articles , inédits auxquels le groupe Systema fait parfois référence. Le plus ancien (1987) établit une liaison entre certains relateurs arithmétiques dégénérés et des algorithmes résolvant certaines équations différentielles (cas de l'oscillateur harmonique quantique par exemple). Dans l'article suivant (1988), sont esquissées des formes de cellules cérébrales (une condition de "bifurcation" est appliquée à un relateur arithmétique biquadratique). Dans le troisième (1988), des relateurs à deux variables d'environnement sont utilisées, à un niveau de synthèse élevé, pour une modélisation de certains phénomènes de vieillissement. La deuxième partie concerne des problèmes généraux (tels que la complexité, les relations entre science et tradition) et des applications spécifiques en physique, biologie, informatique, sciences humaines, socio-économie (communications présentées en août 1992 lors du XIIIe Congrès International de Cybernétique). Les plus récentes publications exploitent la notion de 1 système générique et de 1/2 pilotage. La troisième partie est une synthèse sur les applications des relateurs arithmétiques, rédigée à l'intention des auditeurs de la deuxième Ecole de Systémique (Mont Ste Odile, octobre 1992)

Quelques applications des relateurs arithmétiques : de la physique à la socio-économie (documents anciens inédits et synthèses récentes)

La première partie du rapport de recherche est constituée de trois articles , inédits auxquels le groupe Systema fait parfois référence. Le plus ancien (1987) établit une liaison entre certains relateurs arithmétiques dégénérés et des algorithmes résolvant certaines équations différentielles (cas de l'oscillateur harmonique quantique par exemple). Dans l'article suivant (1988), sont esquissées des formes de cellules cérébrales (une condition de "bifurcation" est appliquée à un relateur arithmétique biquadratique). Dans le troisième (1988), des relateurs à deux variables d'environnement sont utilisées, à un niveau de synthèse élevé, pour une modélisation de certains phénomènes de vieillissement. La deuxième partie concerne des problèmes généraux (tels que la complexité, les relations entre science et tradition) et des applications spécifiques en physique, biologie, informatique, sciences humaines, socio-économie (communications présentées en août 1992 lors du XIIIe Congrès International de Cybernétique). Les plus récentes publications exploitent la notion de 1 système générique et de 1/2 pilotage. La troisième partie est une synthèse sur les applications des relateurs arithmétiques, rédigée à l'intention des auditeurs de la deuxième Ecole de Systémique (Mont Ste Odile, octobre 1992)