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1. Gravitoviscous protoplanetary disks with a dust component: III. Evolution of gas, dust, and pebbles

Author

Elbakyan, V. G., Johansen, A., Lambrechts, M., Akimkin, V., Vorobyov, E. I., Elbakyan, V. G., Johansen, A., Lambrechts, M., Akimkin, V., and Vorobyov, E. I.

Abstract

Aims. We study the dynamics and growth of dust particles in circumstellar disks of different masses that are prone to gravitational instability during the critical first Myr of their evolution. Methods. We solved the hydrodynamics equations for a self-gravitating and viscous circumstellar disk in a thin-disk limit using the FEOSAD numerical hydrodynamics code. The dust component is made up of two different components: micron-sized dust and grown dust of evolving size. For the dust component, we considered the dust coagulation, fragmentation, momentum exchange with the gas, and dust self-gravity. Results. We found that the micron-sized dust particles grow rapidly in the circumstellar disk, reaching a few cm in size in the inner 100 au of the disk during less than 100 kyr after the disk formation, provided that fragmentation velocity is 30 ms-1. Due to the accretion of micron dust particles from the surrounding envelope, which serves as a micron dust reservoir, the approximately cm-sized dust particles continue to be present in the disk for more than 900 kyr after the disk formation and maintain a dust-to-gas ratio close to 0.01. We show that a strong correlation exists between the gas and pebble fluxes in the disk. We find that radial surface density distribution of pebbles in the disk shows power-law distribution with an index similar to that of the Minimum-mass solar nebula regardless the disk mass. We also show that the gas surface density in our models agrees well with measurements of dust in protoplanetary disks of AS 209, HD 163296, and DoAr 25 systems. Conclusions. Pebbles are formed during the very early stages of protoplanetary disk evolution. They play a crucial role in the planet formation process. Our disc simulations reveal the early onset (<105 yr) of an inwards-drifting flux of pebble-sized particles that makes up approximately between one hundredth and one tenth of the gas mass flux, which appears consistent with mm-observations of discs. Such a pebbl

Published
2020

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

Author

Langlois, M., Gratton, R., Lagrange, A. -M., Delorme, P., Boccaletti, A., Bonnefoy, M., Maire, A. -L., Mesa, D., Chauvin, G., Desidera, S., Vigan, A., Cheetham, A., Hagelberg, J., Feldt, M., Meyer, M., Rubini, P., Le, Coroller, H., Cantalloube, F., Biller, B., Bonavita, M., Bhowmik, T., Brandner, W., Daemgen, S., D'Orazi, V., Flasseur, O., Fontanive, C., Galicher, R., Girard, J., Janin-Potiron, P., Janson, M., Keppler, M., Kopytova, T., Lagadec, E., Lannier, J., Lazzoni, C., Ligi, R., Meunier, N., Perreti, A., Perrot, C., Rodet, L., Romero, C., Rouan, D., Samland, M., Salter, G., Sissa, E., Schmidt, T., Zurlo, A., Mouillet, D., Denis, L., Thiébaut, E., Milli, J., Wahhaj, Z., Beuzit, J. -L., Dominik, C., Henning, T., Ménard, F., Müller, A., Schmid, H. M., Turatto, M., Udry, S., Abe, L., Antichi, J., Allard, F., Baruffolo, A., Baudoz, P., Baudrand, J., Bazzon, A., Blanchard, P., Carbillet, M., Carle, M., Cascone, E., Charton, J., Claudi, R., Costille, A., De Caprio, V., Delboulbé, A., Dohlen, K., Fantinel, D., Feautrier, P., Fusco, T., Gigan, P., Giro, E., Gisler, D., Gluck, L., Gry, C., Hubin, N., Hugot, E., Jaquet, M., Kasper, M., Le Mignant, D., Llored, M., Madec, F., Magnard, Y., Martinez, P., Maurel, D., Messina, S., Möller-Nilsson, O., Mugnier, L., Moulin, T., Origné, A., Pavlov, A., Perret, D., Petit, C., Pragt, J., Puget, P., Rabou, P., Ramos, J., Rigal, F., Rochat, S., Roelfsema, R., Rousset, G., Roux, A., Salasnich, B., Sauvage, J. -F., Sevin, A., Soenke, C., Stadler, E., Suarez, M., Weber, L., Wildi, F., and Rickman, E.

Subjects
STATISTICAL [METHODS], IMAGING TECHNIQUES, INFRARED DEVICES, FORMATION [PLANETS AND SATELLITES], DETECTION PERFORMANCE, IMAGE PROCESSING [TECHNIQUES], EXTREMELY LARGE TELESCOPES, COLOR MAGNITUDE DIAGRAMS, ANALYSIS STRATEGIES, FORMATION AND EVOLUTIONS, SEARCH ENGINES, OBSERVATIONAL [METHODS], STATISTICAL PROPERTIES, HIGH ANGULAR RESOLUTION [INSTRUMENTATION], DETECTION [PLANETS AND SATELLITES], ORBITS, LARGE FIELD OF VIEWS, POPULATION STATISTICS, SURVEYS, INTEGRAL FIELD SPECTROGRAPH, STARS, EXTRASOLAR PLANETS
Abstract

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.

Published
2021

3. Discovery of a brown dwarf companion to the star HIP 64892

Author

Cheetham, A., Bonnefoy, M., Desidera, S., Langlois, M., Vigan, A., Schmidt, T., Olofsson, J., Chauvin, G., Klahr, H., Gratton, R., D'Orazi, V., Henning, T., Janson, M., Biller, B., Peretti, S., Hagelberg, J., Ségransan, D., Udry, S., Mesa, D., Sissa, E., Kral, Q., Schlieder, J., Maire, A. -L., Mordasini, C., Menard, F., Zurlo, A., Beuzit, J. -L., Feldt, M., Mouillet, D., Meyer, M., Lagrange, A. -M., Boccaletti, A., Keppler, M., Kopytova, T., Ligi, R., Rouan, D., Le, Coroller, H., Dominik, C., Lagadec, E., Turatto, M., Abe, L., Antichi, J., Baruffolo, A., Baudoz, P., Blanchard, P., Buey, T., Carbillet, M., Carle, M., Cascone, E., Claudi, R., Costille, A., Delboulbé, A., De, Caprio, V., Dohlen, K., Fantinel, D., Feautrier, P., Fusco, T., Giro, E., Gluck, L., Hubin, N., Hugot, E., Jaquet, M., Kasper, M., Llored, M., Madec, F., Magnard, Y., Martinez, P., Maurel, D., Le, Mignant, D., Möller-Nilsson, O., Moulin, T., Origné, A., Pavlov, A., Perret, D., Petit, C., Pragt, J., Puget, P., Rabou, P., Ramos, J., Rigal, F., Rochat, S., Roelfsema, R., Rousset, G., Roux, A., Salasnich, B., Sauvage, J. -F., Sevin, A., Soenke, C., Stadler, E., Suarez, M., Weber, L., Wildi, F., Cheetham, A., Bonnefoy, M., Desidera, S., Langlois, M., Vigan, A., Schmidt, T., Olofsson, J., Chauvin, G., Klahr, H., Gratton, R., D'Orazi, V., Henning, T., Janson, M., Biller, B., Peretti, S., Hagelberg, J., Ségransan, D., Udry, S., Mesa, D., Sissa, E., Kral, Q., Schlieder, J., Maire, A. -L., Mordasini, C., Menard, F., Zurlo, A., Beuzit, J. -L., Feldt, M., Mouillet, D., Meyer, M., Lagrange, A. -M., Boccaletti, A., Keppler, M., Kopytova, T., Ligi, R., Rouan, D., Le, Coroller, H., Dominik, C., Lagadec, E., Turatto, M., Abe, L., Antichi, J., Baruffolo, A., Baudoz, P., Blanchard, P., Buey, T., Carbillet, M., Carle, M., Cascone, E., Claudi, R., Costille, A., Delboulbé, A., De, Caprio, V., Dohlen, K., Fantinel, D., Feautrier, P., Fusco, T., Giro, E., Gluck, L., Hubin, N., Hugot, E., Jaquet, M., Kasper, M., Llored, M., Madec, F., Magnard, Y., Martinez, P., Maurel, D., Le, Mignant, D., Möller-Nilsson, O., Moulin, T., Origné, A., Pavlov, A., Perret, D., Petit, C., Pragt, J., Puget, P., Rabou, P., Ramos, J., Rigal, F., Rochat, S., Roelfsema, R., Rousset, G., Roux, A., Salasnich, B., Sauvage, J. -F., Sevin, A., Soenke, C., Stadler, E., Suarez, M., Weber, L., and Wildi, F.

Abstract

We report the discovery of a bright, brown dwarf companion to the star HIP 64892, imaged with VLT/SPHERE during the SHINE exoplanet survey. The host is a B9.5V member of the Lower-Centaurus-Crux subgroup of the Scorpius Centaurus OB association. The measured angular separation of the companion (1.2705 ± 0.0023”) corresponds to a projected distance of 159 ± 12 AU. We observed the target with the dual-band imaging and long-slit spectroscopy modes of the IRDIS imager to obtain its spectral energy distribution (SED) and astrometry. In addition, we reprocessed archival NACO L-band data, from which we also recover the companion. Its SED is consistent with a young (<30 Myr), low surface gravity object with a spectral type of M9γ ± 1. From comparison with the BT-Settl atmospheric models we estimate an effective temperature of Teff = 2600 ± 100 K, and comparison of the companion photometry to the COND evolutionary models yields a mass of ∼29−37 MJ at the estimated age of 16+−157 Myr for the system. The star HIP 64892 is a rare example of an extreme-mass ratio system (q ∼ 0.01) and will be useful for testing models relating to the formation and evolution of such low-mass objects. © ESO 2018

Published
2018

4. Gravitoviscous protoplanetary disks with a dust component

Author

Vitaly Akimkin, Michiel Lambrechts, Anders Johansen, Vardan G. Elbakyan, and Eduard I. Vorobyov

Subjects
Mass flux, Planetesimal, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, DUST, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, GASES, Protoplanetary disk, NUMERICAL HYDRODYNAMICS, 01 natural sciences, HYDRODYNAMICS, Planet, FORMATION [STARS], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, DENSITY OF GASES, Pebble, 010303 astronomy & astrophysics, SOLAR POWER GENERATION, Astrophysics::Galaxy Astrophysics, HYDRODYNAMICS EQUATION, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, POWER LAW DISTRIBUTION, GRAVITATION, Astronomy and Astrophysics, Accretion (astrophysics), FORMATION AND EVOLUTIONS, 13. Climate action, Space and Planetary Science, GRAVITATIONAL INSTABILITY, Streaming instability, Astrophysics::Earth and Planetary Astrophysics, GLOBAL NUMERICAL SIMULATIONS, Formation and evolution of the Solar System, SURFACE DENSITY DISTRIBUTION, PROTOPLANETARY DISKS, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

We study the dynamics and growth of dust particles in circumstellar disks of different masses that are prone to gravitational instability during the critical first Myr of their evolution. The dust component is made up of two different components: micron-sized dust and grown dust of evolving size. For the dust component, we considered the dust coagulation, fragmentation, momentum exchange with the gas, and dust self-gravity. We found that the micron-sized dust particles grow rapidly in the circumstellar disk, reaching a few cm in size in the inner 100 au of the disk during less than 100 kyr after the disk formation, provided that fragmentation velocity is $30\rm~ms^{-1}$. Due to the accretion of micron dust particles from the surrounding envelope, which serves as a micron dust reservoir, the approximately cm-sized dust particles continue to be present in the disk for more than 900 kyr after the disk formation and maintain a dust-to-gas ratio close to 0.01. We show that a strong correlation exists between the gas and pebble fluxes in the disk. We find that radial surface density distribution of pebbles in the disk shows power-law distribution with an index similar to that of the Minimum-mass solar nebula (MMSN) regardless the disk mass. We also show that the gas surface density in our models agrees well with measurements of dust in protoplanetary disks of AS 209, HD 163296, and DoAr 25 systems. Pebbles are formed during the very early stages of protoplanetary disk evolution. They play a crucial role in the planet formation process. Our disc simulations reveal the early onset ($, 13 pages, 10 figures

Published
2020

5. Discovery of a brown dwarf companion to the star HIP 64892

Author

Jacopo Antichi, L. Weber, E. Sissa, Johan Olofsson, H. Le Coroller, Markus Kasper, Damien Ségransan, Alain Roux, T. Buey, Alice Zurlo, Cyril Petit, Alain Delboulbé, Andrea Baruffolo, Thomas Henning, Arnaud Sevin, P. Blanchard, Ronald Roelfsema, Daniela Fantinel, Alain Origne, R. Ligi, Anne Costille, M. Carle, Kjetil Dohlen, François Ménard, Bernardo Salasnich, Maud Langlois, Pierre Baudoz, V. De Caprio, Enrico Giro, D. Maurel, Lyu Abe, Markus Janson, O. Möller-Nilsson, Raffaele Gratton, Jean-Luc Beuzit, Riccardo Claudi, Beth Biller, Eric Stadler, Valentina D'Orazi, Massimo Turatto, Marc Jaquet, Joshua E. Schlieder, Pascal Puget, Taisiya Kopytova, Yves Magnard, Arthur Vigan, C. Soenke, Anthony Cheetham, Anne-Lise Maire, Patrice Martinez, D. Le Mignant, Gérard Rousset, A. Pavlov, Norbert Hubin, M. Keppler, Anne-Marie Lagrange, Emmanuel Hugot, Eric Lagadec, Hubert Klahr, Daniel Rouan, Dino Mesa, Michael Meyer, Thierry Fusco, Janis Hagelberg, Markus Feldt, Philippe Feautrier, Joany Andreina Manjarres Ramos, Quentin Kral, M. Llored, E. Cascone, Marcel Carbillet, S. Rochat, T. O. B. Schmidt, Mickael Bonnefoy, T. Moulin, S. Peretti, P. Rabou, David Mouillet, L. Gluck, J. Pragt, Gael Chauvin, F. Madec, Jean-François Sauvage, Francois Wildi, C. Mordasini, Denis Perret, Carsten Dominik, Anthony Boccaletti, F. Rigal, Marcos Suarez, Stéphane Udry, Silvano Desidera, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Universidad de Chile, Universidad de Valparaiso [Chile], Stockholm University, University of Edinburgh, Instituto de Astronomia y ciencias Planetarias de Atacama (INCT), Universidad de Atacama, University of Cambridge [UK] (CAM), NASA Goddard Space Flight Center (GSFC), University of Bern, Universidad Diego Portales [Santiago] (UDP), Institute for Particle Physics and Astrophysics [ETH Zürich] (IPA), Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Mathematics - University of Michigan, University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Arizona State University [Tempe] (ASU), Ural Federal University [Ekaterinburg] (UrFU), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), INAF - Osservatorio Astronomico di Capodimonte (OAC), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), European Southern Observatory (ESO), NOVA Optical Infrared Instrumentation Group, European Southern Observatory [Santiago] (ESO), Université de Genève = University of Geneva (UNIGE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidad de Chile = University of Chile [Santiago] (UCHILE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Low Energy Astrophysics (API, FNWI), Department of Physical Geography and Ecosystem Science [Lund], Lund University [Lund], Institute for Astronomy [Edinburgh] (IfA), Geneva Observatory, Department of Biochemistry and Molecular Biology, Mayo Clinic, Observatoire de Paris, Université Paris sciences et lettres (PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], INDIVIDUAL: HIP 64892 [STARS], HIGH ANGULAR RESOLUTIONS [TECHNIQUES], 530 Physics, Astrophysics::High Energy Astrophysical Phenomena, BROWN DWARFS, FOS: Physical sciences, Library science, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, DETECTIONS [PLANETS AND SATELLITES], OPTIQUE ADAPTATIVE, 01 natural sciences, Techniques: high angular resolution, VLT, 0103 physical sciences, DETECTION [PLANETS AND SATELLITES], Astrophysics::Solar and Stellar Astrophysics, European commission, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Stars: brown dwarfs individual: HIP 64892, HIGH ANGULAR RESOLUTION [TECHNIQUES], Earth and Planetary Astrophysics (astro-ph.EP), Physics, ASTRONOMIE, INDIVIDUAL [STARS], 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, EFFECTIVE TEMPERATURE, Astronomy and Astrophysics, Planets and satellites: detection, 500 Science, 620 Engineering, EVOLUTIONARY MODELS, Astrophysics - Solar and Stellar Astrophysics, FORMATION AND EVOLUTIONS, Space and Planetary Science, ATMOSPHERES [SATELLITES], SPECTRAL ENERGY DISTRIBUTION, Christian ministry, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], SATELLITES, STARS, Astrophysics - Earth and Planetary Astrophysics, PLANETS
Abstract

We report the discovery of a bright, brown dwarf companion to the star HIP 64892, imaged with VLT/SPHERE during the SHINE exoplanet survey. The host is a B9.5V member of the Lower-Centaurus-Crux subgroup of the Scorpius Centaurus OB association. The measured angular separation of the companion ($1.2705\pm0.0023$") corresponds to a projected distance of $159\pm12$ AU. We observed the target with the dual-band imaging and long-slit spectroscopy modes of the IRDIS imager to obtain its SED and astrometry. In addition, we reprocessed archival NACO L-band data, from which we also recover the companion. Its SED is consistent with a young (, Comment: 12 pages, 11 figures, accepted for publication in A&A

Published
2018

6. Spatiotemporal Instability Of Femtosecond Pulses In Graded-Index Multimode Fibers

Author

Bülend Ortaç and Uğur Teğin

Subjects
Spatiotemporal pulse, Ultra-short pulses, Frequency shift, Physics::Optics, Electromagnetic pulse, 02 engineering and technology, 01 natural sciences, Instability, Ultrashort pulses, 010309 optics, Amplitude modulation, 020210 optoelectronics & photonics, Optics, Nonlinear fiber optics, 0103 physical sciences, Attractor, Dispersion (optics), 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Spatiotemporal pulse propagation, Ultrafast lasers, Physics, Multi-mode optical fiber, Graded-Index Multimode fibers, business.industry, Pulse propagation model, Formation and evolutions, Spatial evolution, Spatio-temporal instability, Multimode fibers, Normal dispersion, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Fibers, Wavelength, Femtosecond, Nonlinear Fiber-Optics, business, Stability
Abstract

We study the spatiotemporal instability generated by a universal unstable attractor in normal dispersion graded-index multimode fiber for femtosecond pulses for the first time. Experimentally observed spatiotemporal instability sidebands are 91-THz detuned from the pump wavelength of 800 nm. Detailed analysis carried out numerically by employing coupled-mode pulse propagation model. Numerically obtained results are well-aligned with experimental observations. Spatial evolution of the total field and spatiotemporal instability sidebands is calculated numerically, and for the input pulses of 200-fs duration, formation and evolution of spatiotemporal instability are shown in both spatial and temporal domains. Our results present the unique features of spatiotemporal instability, such as remarkable frequency shift with inherited beam shape of instability sidebands.

Published
2017

7. Review of scientific topics for the Millimetron Space Observatory

Author

Kardashev, N. S., Novikov, I. D., Lukash, V. N., Pilipenko, S. V., Mikheeva, E. V., Bisikalo, D. V., Wiebe, D. S., Doroshkevich, A. G., Zasov, A. V., Zinchenko, I. I., Ivanov, P. B., Kostenko, V. I., Larchenkova, T. I., Likhachev, S. F., Malov, I. F., Malofeev, V. M., Pozanenko, A. S., Smirnov, A. V., Sobolev, A. M., Cherepashchuk, A. M., and Shchekinov, Yu. A.

Subjects
ASTROPHYSICS, ASTRONOMICAL OBSERVATION, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, COSMOLOGICAL MODELING, OBSERVATORIES, Astrophysics::Cosmology and Extragalactic Astrophysics, VERY LONG BASELINE INTERFEROMETERS, FORMATION AND EVOLUTIONS, COSMOLOGY, MILLIMETER WAVES, TELESCOPES, MILLIMETER WAVELENGTH, Astrophysics::Earth and Planetary Astrophysics, BLACK HOLES, SPACE OBSERVATORIES, Astrophysics::Galaxy Astrophysics, INTERSTELLAR MEDIUMS
Abstract

This paper reviews a wide range of questions in astrophysics and cosmology that can be answered by astronomical observations in the far-IR to millimeter wavelength range and which include the formation and evolution of stars and planets, galaxies, and the interstellar medium, the study of black holes, and the development of the cosmological model. These questions are considered in relation to the Millimetron Space Observatory (Spectrum-M project), which is equipped with a 10 m aperture cooled telescope and can operate both as a single-dish telescope and as part of a space±ground very long baseline interferometer. © 2014 Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences.

Published
2014

8. The effect of Ge content on the formation and evolution of 113 defects in SiGe alloys

Author

Filadelfo Cristiano, Amine Belafhaili, Alain Claverie, L. Laânab, Nikolay Cherkashin, LCS, Faculty of Sciences. Mohammed V University of Rabat, Équipe Matériaux et Procédés pour la Nanoélectronique (LAAS-MPN), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Université Mohammed V de Rabat [Agdal] (UM5), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Équipe Matériaux et Procédés pour la Nanoélectronique ( LAAS-MPN ), Laboratoire d'analyse et d'architecture des systèmes [Toulouse] ( LAAS ), Centre National de la Recherche Scientifique ( CNRS ) -Université Toulouse III - Paul Sabatier ( UPS ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Institut National Polytechnique [Toulouse] ( INP ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Toulouse III - Paul Sabatier ( UPS ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Institut National Polytechnique [Toulouse] ( INP ), Matériaux et dispositifs pour l'Electronique et le Magnétisme ( CEMES-MEM ), Centre d'élaboration de matériaux et d'études structurales ( CEMES ), Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Toulouse III - Paul Sabatier ( UPS ), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées

Subjects
End-of-range defects, Materials science, Annealing (metallurgy), chemistry.chemical_element, Germanium, Pre-amorphization, Quasi-linear functions, Defects evolution, Transport capacity, ComputingMilieux_MISCELLANEOUS, Silicon alloys, [PHYS]Physics [physics], [ PHYS ] Physics [physics], Condensed matter physics, Imaging conditions, Formation and evolutions, Condensed Matter Physics, Amorphization, Crystallography, Ion implantation, chemistry, Transmission electron microscopy, Quasi linear, Defects, Si-Ge alloys
Abstract

cited By 1; International audience; The aim of this work is to study the influence of the Ge content on the 113 defects formed, after a (35 keV, 1 × 1015 Ge+/cm2) preamorphization step followed by annealing at 680 °C, in relaxed SiGe alloys. For that, plan-view Transmission Electron Microscopy (PTEM) under appropriate imaging conditions was used to study the 113 defects evolution as a function of the Ge content. Experimental results show that, increasing the Ge content results in a net reduction of both the density and the size of the 113 defects. Results analysis was performed in the framework of the "excess interstitials" model which describes perfectly the observed decrease of the 113 defects density in Si. Moreover, through a confrontation between the TEM observations and the predictions of this model, we show that the density of the interstitials contained in the defects (deduced from PTEM images) is a quasi linear function of the density of excess interstitials generated during the preamorphization step beneath the c/a interface, as calculated by the SRIM code. We conclude that collisional arguments can appropriately explain the observed evolution of the 113 defects density as a function of the Ge content. Meanwhile, the observed reduction of the 113 defects size with the Ge content, may be ascribed to a decrease of the transport capacity DiCi*, responsible for the defects growth. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Published
2014

9. A study of the counter rotating vortex rings interacting with the primary vortex ring in shock tube generated flows

Author

Somsubhra De, C. L. Dora, Debopam Das, T. Murugan, and Pankaj Kumar

Subjects
Tubes (components), General Physics and Astronomy, Runge-kutta schemes, Shock tubes, Starting vortex, Physics::Fluid Dynamics, Shear flow, symbols.namesake, Primary vortex, Horseshoe vortex, Optical shadowgraphs, Pulse amplitude, Fluid Flow and Transfer Processes, Physics, Counter-rotating vortices, Mach number, Shock (fluid dynamics), Mechanical Engineering, Vortex flow, Mechanics, Vorticity, Formation and evolutions, Navier Stokes equations, Vortex ring, Vortex, Pulse durations, Classical mechanics, Runge Kutta methods, symbols, Numerical results, Burgers vortex, Flow visualization
Abstract

The formation and evolution of counter rotating vortex rings (CRVRs) appearing in shock tube-generated flows at high shock Mach numbers (M) have been studied numerically by solving ax symmetric Navier-Stokes equations and compared with experiments. The AUSM + scheme is used for convective terms, and for time stepping a four-stage Runge-Kutta scheme is used. High-speed smoke flow visualizations and optical shadowgraph techniques are employed for verifying the numerical results. It is observed that the strong shear layer formed near the Mach disc in the axial region of the vortex ring plays a dominant role in CRVR formation. A series of CRVRs is formed for longer driver section and higher M as the shear layer persists for longer duration. The interaction of these CRVRs with the primary vortex and trailing jet vortices is studied for (i) different pressure-pulse durations at the open end keeping the amplitude constant, and (ii) varying pulse amplitude when the duration is fixed. Results are also presented comparing a high-amplitude case against a lower-amplitude one with a longer pulse duration. The maximum vorticity inside the first CRVR is found to be higher than the primary vortex ring during its formation. � 2013 The Japan Society of Fluid Mechanics and IOP Publishing Ltd.

Published
2013

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