BEAST detection of a brown dwarf and a low-mass stellar companion around the young bright B star HIP 81208

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.Comment: 18 pages, 14 figures, 5 tables Accepted for publication in the 10. Planets and planetary systems section of A&

The B-Star Exoplanet Abundance Study: a co-moving 16-25 Mjup companion to the young binary system HIP 79098

Wide low-mass substellar companions are known to be very rare among low-mass stars, but appear to become increasingly common with increasing stellar mass. However, B-type stars, which are the most massive stars within ~150 pc of the Sun, have not yet been examined to the same extent as AFGKM-type stars in that regard. In order to address this issue, we launched the ongoing B-star Exoplanet Abundance Study (BEAST) to examine the frequency and properties of planets, brown dwarfs, and disks around B-type stars in the Scorpius-Centaurus (Sco-Cen) association; we also analyzed archival data of B-type stars in Sco-Cen. During this process, we identified a candidate substellar companion to the B9-type spectroscopic binary HIP 79098 AB, which we refer to as HIP 79098 (AB)b. The candidate had been previously reported in the literature, but was classified as a background contaminant on the basis of its peculiar colors. Here we demonstrate that the colors of HIP 79098 (AB)b are consistent with several recently discovered young and low-mass brown dwarfs, including other companions to stars in Sco-Cen. Furthermore, we show unambiguous common proper motion over a 15-year baseline, robustly identifying HIP 79098 (AB)b as a bona fide substellar circumbinary companion at a 345+/-6 AU projected separation to the B9-type stellar pair. With a model-dependent mass of 16-25 Mjup yielding a mass ratio of <1%, HIP 79098 (AB)b joins a growing number of substellar companions with planet-like mass ratios around massive stars. Our observations underline the importance of common proper motion analysis in the identification of physical companionship, and imply that additional companions could potentially remain hidden in the archives of purely photometric surveys.Comment: 9 pages, 6 figures, accepted for publication in A&

La montagne explorée, étudiée et représentée : évolution des pratiques culturelles depuis le xviiie siècle

Le Siècle des lumières, qui consacre l’ouverture des élites européennes à la modernité scientifique, est aussi celui qui pousse les mêmes sociétés vers les sommets et les glaciers des montagnes. Objet de fascination et non plus de crainte, la montagne apparaît, à la suite de Rousseau et Senancour, dans toute sa majesté, à la fois vierge, mystérieuse, repliée sur elle-même et porteuse d’un message d’universalité. Après avoir longtemps suscité peur et préjugés depuis l’Antiquité, la montagne est devenue au xviiie siècle un territoire de conquête et de découverte générant toute une mythologie et un imaginaire qui vont modifier le rapport des sociétés européennes avec le milieu des sommets. Le Congrès national des sociétés historiques et scientifiques rassemble chaque année universitaires, membres de sociétés savantes et jeunes chercheurs. Ce recueil est issu de travaux présentés lors du 142e Congrès sur le thème « Circulations montagnardes, circulations européennes »

Augmented reality versus classical HUD to take over from automated driving: an aid to smooth reactions and to anticipate maneuvers

International audienc

Augmented reality versus classical HUD to take over from automated driving: an aid to smooth reactions and to anticipate maneuvers

International audienc

Augmented reality HUD vs. conventional HUD to perform a navigation task in a complex driving situation

International audienceThis study aims at investigating the added value of an augmented reality head-up display (AR-HUD) in relation to a con- ventional head-up display (C-HUD) to perform navigation tasks in a complex road situation. The notion of complexity was defined according to two main factors: infrastructure and traffic. It was used to identify and select real road situations pre- senting different sources of complexity. This study focuses on one of these situations, which was reproduced on a simulator and broken down into three use cases. A total of 32 participants performed three navigation tasks, using the AR-HUD or the C-HUD. Both objective and subjective data were collected. Data analyses, using linear mixed model analyses of variance and multilevel logistic regression, indicate a slight advantage of the AR-HUD. Participants using the AR-HUD make fewer errors and drive faster on average. Moreover, the AR-HUD is assessed to be more useful and easier to understand than the C-HUD. However, this interface shows limitations, in particular, because it does not enable drivers to anticipate the manoeuvre to be made. The study raises questions about the design of an instrument system that would help drivers not only identify, but also build a representation of a forthcoming manoeuvre to be performed

Augmented reality for pedestrian detection: first elements about a study conducted on a real car

International audienceHead-up displays (HUD) permit registered augmentedreality in cars. It is a powerful tool to enhance safety onroad and help the driver to be more aware of hisdriving environment. In this study frame, we have usedan AR HUD system embedded in a car and testedreactions of people driving this car in a scenario ofpedestrian detection with a HMI design adapted to thispurpose

Does the Type of Visualization Influence the Mode of Cognitive Control in a Dynamic System?

International audienceThis study investigates the influence of a visualization system on the mode of cognitive control adopted in a navigation task. It relies on a driving simulator experiment. It uses data clustering methods, which help identify three pat-terns of in-vehicle data corresponding to three different modes of control. The study shows that Augmented Reality HUD supports drivers, since it contrib-utes to avoiding the adoption of a scrambled mode of control. However, it promotes an opportunistic mode of control characterised by a higher but lim-ited anticipation

Virtual Head-up Displays for Augmented Reality in Cars: A User Testing to validate the Congruence

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