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(10) Hygiea is the fourth largest main belt asteroid and the only known asteroid whose surface composition appears similar to that of the dwarf planet (1) Ceres 1 , 2 , suggesting a similar origin for these two objects. Hygiea suffered a giant impact more than 2 Gyr ago 3 that is at the origin of one of the largest asteroid families. However, Hygeia has never been observed with sufficiently high resolution to resolve the details of its surface or to constrain its size and shape. Here, we report high-angular-resolution imaging observations of Hygiea with the VLT/SPHERE instrument (~20 mas at 600 nm) that reveal a basin-free nearly spherical shape with a volume-equivalent radius of 217 ± 7 km, implying a density of 1,944 ± 250 kg m − 3 to 1 σ . In addition, we have determined a new rotation period for Hygiea of ~13.8 h, which is half the currently accepted value. Numerical simulations of the family-forming event show that Hygiea’s spherical shape and family can be explained by a collision with a large projectile (diameter ~75–150 km). By comparing Hygiea’s sphericity with that of other Solar System objects, it appears that Hygiea is nearly as spherical as Ceres, opening up the possibility for this object to be reclassified as a dwarf planet. SPHERE at the VLT observed Hygiea, the fourth largest body in the main belt and the parent body of a big asteroid family, at unprecedented spatial resolution. Its unexpected spherical shape without any impact crater is explained by numerical simulations with a big impact that fluidized the body, reassembling it in a rotational equilibrium regime.

Reaching the high angular resolution and contrast level desired for exoplanetary science requires us to equip large telescopes with extreme adaptive optics (XAO) systems to compensate for the effect of the atmospheric turbulence at a very fast rate. This calls for the development of ultra-sensitive wavefront sensors (WFSs), such as Fourier filtering wavefront sensors (FFWFSs), to be operated at low flux, as well as an increase in the XAO loop frame rate. These sensors, which constitute the baseline for current and future XAO systems, exhibit such a high sensitivity at the expense of a non-linear behaviour that must be properly calibrated and compensated for to deliver the required performance. We aim to validate on-sky a recently proposed method that associates the FFWFS with a focal plane detector, the gain scheduling camera (GSC), to estimate in real time the first-order terms of the sensor non-linearities, known as modal optical gains. We implemented a GSC on the adaptive-optics (AO) bench PAPYRUS to be associated with the existing pyramid wavefront sensor (PWFS). We compared experimental results to expected results obtained with a high-fidelity numerical twin of the AO system. We validated experimentally the method both in laboratory and on-sky. We demonstrated the capability of the GSC to accurately estimate the optical gains of the PWFS at 100 Hz, corresponding to the current limit in speed imposed by PAPYRUS hardware, but it could be applied at higher frequencies to enable frame-by-frame optical gains tracking. The presented results exhibit good agreement on the optical gains estimation with respect to numerical simulations reproducing the experimental conditions tested. Our experimental results validate the strategy of coupling a FFWFS with a focal-plane camera to master the non-linearities of the sensor. This demonstrates its attractiveness for future XAO application.

The Provence Adaptive optics Pyramid Run System (PAPYRUS) is a pyramid-based Adaptive Optics (AO) system that will be installed at the Coude focus of the 1.52m telescope (T152) at the Observatoire de Haute Provence (OHP). The project is being developed by PhD students and Postdocs across France with support from staff members consolidating the existing expertise and hardware into an R&D testbed. This testbed allows us to run various pyramid wavefront sensing (WFS) control algorithms on-sky and experiment on new concepts for wavefront control with additional benefit from the high number of available nights at this telescope. It will also function as a teaching tool for students during the planned AO summer school at OHP. To our knowledge, this is one of the first pedagogic pyramid-based AO systems on-sky. The key components of PAPYRUS are a 17x17 actuators Alpao deformable mirror with a Alpao RTC, a very low noise camera OCAM2k, and a 4-faces glass pyramid. PAPYRUS is designed in order to be a simple and modular system to explore wavefront control with a pyramid WFS on sky. We present an overview of PAPYRUS, a description of the opto-mechanical design and the current status of the project.

Direct detection and spectral characterization of extrasolar planets is one of the most exciting but also one of the most challenging area in modern astronomy. For its second generation instrumentation on the VLT, ESO has supported two phase A studies for a so-called “Planet Finder” dedicated instrument. Based on the results of these two studies, a unique instrument is now considered for first light in early 2010, including a powerful extreme adaptive optics system, various coronagraphs, an infrared differential imaging camera, an infrared integral field spectrograph and a visible differential polarimeter. We will briefly summarize the science objectives and requirements, describe the proposed conceptual design and discuss the main limitations and corresponding instrumental issues of such a system. We will also derive the expected performance of the proposed Planet Finder and present the project organization.

The Portfolio presented here is concerned with the subject of Authentic Leadership Development. This subject has become the focus of much attention in the last 10 years by both researchers and practitioners in the leadership and leadership development field. Over the decades there has been a variety of leadership themes and concepts that have garnered similar attention, for example, Transformational & Transactional Leadership, Situational Leadership, Servant Leadership, Contingent Leadership, Ethical Leadership…and now Authentic Leadership. It has probably come to the fore as a result of high profile examples of poor leadership on a global scale. Even before the financial crisis of 2008 there were the examples of Enron and Worldcom and since 2008 there have been the examples of Arthur Andersen and Lehman Brothers (http://www.accounting-degree.org/scandals) and more recently Toshiba, Volkswagen and even FIFA (http://fortune.com/2015/12/27/biggest-corporate-scandals-2015). Although over this last decade there has been this considerable interest in the idea of Authentic Leadership, both as a construct and an effective form of leadership practice, what has been notably lacking, particularly in the academic field, are ideas of how to actually develop authentic leaders. Both anecdotal evidence from the practitioners and empirical evidence from the researchers all point towards Authentic Leadership achieving desirable organisational and business benefits. Yet there is almost a complete absence of any research demonstrating how Authentic Leadership is actually developed. This is the sole purpose of this piece of research, to investigate one particular approach to Authentic Leadership Development (ALD) to see if it works and if so, to try and understand how it works.

In the frame of the VLT Planet-Finder project, the phase A system study has demonstrated the feasibility of an extreme adaptive optics system aimed at the direct detection of extrasolar giant planets. The main results of this study are presented in this paper.

We present experimental results of a new procedure of measurement and pre-compensation of the non-common path aberrations in Adaptive Optics. A significant Strehl ratio increase (from 70 to 95.5 % in R band) is demonstrated.

A highlight science case for the European ELT is: First light - The First Galaxies and the Ionization State of the Early Universe. It aims at understanding the formation and evolution of the first sources of light at the end of the Dark Ages and of the re-ionization of the Universe. The corresponding instrument requirements are: a few tens of integral field units with spatial sampling $\\sim$20mas and individual fields of ${\\sim}1''$ over a wide field of view of $5' \\times 5'$ or larger. Multi-Object Adaptive Optics is required to locally provide significant image quality enhancement. Spectroscopic observations are required in the near IR domain with a spectral resolution of a few 1000. MOMFIS is a preliminary instrument concept designed for OWL around this science case. The instrument concept and preliminary design are presented. Development efforts are estimated, as well as development risks and required R&D activities.

In this paper, we present a first comparison of different Adaptive Optics (AO) concepts to reach a given scientific specification for 3D spectroscopy on Extremely Large Telescope (ELT). We consider that a range of 30%–50% of Ensquarred Energy (EE) in H band (1.65$\\mu$m) and in an aperture size from 25 to 100mas is representative of the scientific requirements. From these preliminary choices, different kinds of AO concepts are investigated: Ground Layer Adaptive Optics (GLAO), Multi-Object AO (MOAO) and Laser Guide Stars AO (LGS). Using Fourier based simulations we study the performance of these AO systems depending on the telescope diameter.

The detection of telluric extra-solar planets implies an extremely high contrast long exposure imaging capability at near-infrared and probably visible wavelengths. We present here the core of any Planet Finder instrument which is the extreme AO sub-system. The level of AO correction directly impacts on the exposure time required for planet detection. The extreme adaptive optics system has to correct for the perturbation induced by the atmospheric turbulence as well as for the internal aberrations of the instrument itself. An example of application is proposed in the frame of the EPICS project (XAO system for the ESO OWL telescope).