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1. On deviations from free-radial outflow in the inner coma of comet 67P/Churyumov–Gerasimenko

Author: Olivier Groussin, Björn Davidsson, Giampiero Naletto, S. Fornasier, Cecilia Tubiana, Horst Uwe Keller, P. L. Lamy, Michael Küppers, J.F. Wu, Hans Rickman, M. A. Barucci, W-H. Ip, Ekkehard Kührt, Stubbe F. Hviid, Selina-Barbara Gerig, L. M. Lara, C. C. Su, Marco Fulle, Nilda Oklay, R. Rodrigo, Monica Lazzarin, Stefano Mottola, Jean-Baptiste Vincent, V. Da Deppo, Laurent Jorda, Jörg Knollenberg, P. J. Gutierrez, Stefano Debei, Frank Scholten, G. Cremonese, M. De Cecco, Holger Sierks, Frank Preusker, J. L. Bertaux, Cesare Barbieri, Jakob Deller, Raphael Marschall, Dennis Bodewits, J. J. Lopez Moreno, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Carsten Güttler, Jessica Agarwal, Imre Tóth, Francesco Marzari, J.-R. Kramm, Swiss National Science Foundation, European Commission, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, 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), INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität Bern [Bern], Institute of Space Science [Taiwan], Max-Planck-Institut für Sonnensystemforschung (MPS), Max Planck Institute for Solar System Research (MPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), University of Bern (UBERN), International Space Science Institute (ISSI), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Department of Astronomy, University of Maryland, Jet Propulsion Laboratory, California Institute of Technology (JPL), INAF - Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy, Graduate Institute of Astronomy, Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Science Operations Department, European Space Astronomy Centre/ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics, National Tsing Hua University, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany, Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, 35122 Padova, Italy, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Space Research Center, Polish Academy of Sciences (Warsaw), Observatoire de Paris, Université Paris sciences et lettres (PSL), CNR-IFN UOS Padova LUXOR, Università di Trento (UNITN), Instituto de Astrofisica de Andalucia, CSIC (IAA), Dipartimento di Fisica, Università di Padova, Universita degli Studi di Padova, California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Technische Universität Braunschweig [Braunschweig], 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), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)
Subjects: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Infrared, 67P/Churyumov–Gerasimenko, Astrophysics, Dust, Inner coma, OSIRIS, Rosetta, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Magnetosphere particle motion, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Particle acceleration, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Outflow, Direct simulation Monte Carlo, Astrophysics::Earth and Planetary Astrophysics, Test particle, Impact parameter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed. For commercial reuse, permission must be requested below., The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the dust outflow in the innermost coma of 67P. The aim is to determine the global dust outflow behaviour and place constraints on physical processes affecting particles in the inner coma. We study the coma region right above the nucleus surface, spanning from the nucleus centre out to a distance of about 50 km comet centric distance (approximately 25 average comet radii). We primarily adopt an approach used by Thomas and Keller (1990) to study the dust outflow. We present the effects on azimuthally-averaged values of the dust reflectance of non-radial flow and non-point-source geometry, acceleration of dust particles, sublimation of icy dust particles after ejection from the surface, dust particle fragmentation, optical depth effects and the influence of gravitationally bound particles. All of these physical processes could modify the observed distribution of light scattered by the dust coma. In the image analysis, profiles of azimuthally averaged dust brightness as a function of impact parameter b (azimuthal average, “Ā-curve”) were fitted with a simple function that best fits the shape of our profile curves (f(b;u,v,w,z)=u/b+wb+z). The analytical fit parameters (u, v, w, z), which hold the key information about the dust outflow behaviour, were saved in a comprehensive database. Through statistical analysis of these information, we show that the spatial distribution of dust follows free-radial outflow behaviour (i.e. force-free radial outflow with constant velocity) beyond distances larger than ∼11.9 km from the comet centre, which corresponds to a relative distance of about 6 average comet radii from the comet centre. Hence, we conclude that beyond this distance, and on average, fragmentation and gravitationally bound particles are negligible processes in determining the optically scattered light distribution in the innermost coma. Closer to the nucleus we observe dust outflow behaviour that deviates from free-radial outflow. A comparison of our result profiles with numerical models using a Direct Simulation Monte Carlo (DSMC) approach with dust particle distributions calculated using a test particle approach has been used to demonstrate the influence of a complex shape and particle acceleration on the azimuthal average profiles. We demonstrate that, while other effects such as fragmentation or sublimation of dust particles cannot be ruled out, acceleration of the dust particles and effects arising from the shape of the irregular nucleus (non-point source geometry) are sufficient to explain the observed dust outflow behaviour from image data analysis. As a by-product of this work, we have calculated “Afρ” values for the 1/r regime. We found a peak in the coma activity in terms of Afρ (normalised to a phase angle of 90°) of ∼210 cm 20 days after perihelion. Furthermore, based on simplified models of particle motion within bound orbits, it is shown that limits on the total cross-sectional area of bound particles might be derived through further analysis. An example is given. © 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2. The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.
Published: 2018
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2. Accurate rho and log g of delta Sct stars using Asteroseismology

Author: García Hernández, A., Monteiro, M. J. P. F. G., Guo, Z., Reese, Daniel, Suárez, Juan Carlos, Martin-Ruiz, Susana, Pascual-Granado, Javier, Moya, Andrés, Garrido, Rafael, Centro de Astrofisica da Universidade do Porto (CAUP), Center for High Angular Resolution Astronomy, Department of Physics and Astronomy, Georgia State University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Etoile, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Universidad de Granada = University of Granada (UGR), Instituto de Astrofisica de Andalucia, CSIC (IAA), Universitat Internacional Valenciana (VIU), Mario J. P. F. G. Monteiro, Margarida S. Cunha, and Joao Miguel T. Ferreira
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; In this work, we present a new method to determine the surface gravity of delta Sct stars. We used a refined Delta nu-rho relation and the stellar parallaxes or luminosities to determine their masses and radii. A comparison with the data obtained from the binary analysis, has shown that the values found by both methods are equivalent, within the uncertainties. Moreover, thanks to the refined relation, the uncertainties in log g are of the order of those usually estimated with high-resolution spectroscopy. Because of that, this new method to determine the surface gravity is an important step-forward to break the degeneracy problem in the spectroscopic analysis.
Published: 2016

3. EURONEAR—Recovery, follow-up and discovery of NEAs and MBAs using large field 1–2m telescopes

Author: D. Dumitru, A. Sonka, David Asher, Iulia M. Comsa, Javier Licandro, T. Badescu, A. Nedelcu, Eduardo Unda-Sanzana, C. Vancea, A. Barr, R. Toma, J. L. Ortiz, D. Vidican, Ovidiu Vaduvescu, F. Pozo, Mirel Birlan, M. Constantinescu, M. Badea, Marcel Popescu, C. Opriseanu, A. Tudorica, Isaac Newton Group of Telescopes, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomical Institute of the Romanian Academy, Bucharest, Bonn Cologne Graduate School of Physics and Astronomy, Astronomical Observatory 'Admiral Vasile Urseanu', Instituto de Astronomia, Universidad Catolica del Norte, Armagh Observatory, College Hill, Instituto de Astrofísica de Canarias (IAC), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astroclubul Bucuresti, Department of Physics, University of Bucharest, Rheinische Friedrich-Wilhelms-Universität Bonn, and Faculty of Mathematics and Informatics, Babes-Bolyai University
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Orbital elements, Physics, Near-Earth object, media_common.quotation_subject, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrometry, Astrophysics, law.invention, Telescope, Space and Planetary Science, Asteroid, Sky, law, Evaluation methods, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, media_common
Abstract: We report on the follow-up and recovery of 100 program NEAs, PHAs and VIs using the ESO/MPG 2.2m, Swope 1m and INT 2.5m telescopes equipped with large field cameras. The 127 fields observed during 11 nights covered 29 square degrees. Using these data, we present the incidental survey work which includes 558 known MBAs and 628 unknown moving objects mostly consistent with MBAs from which 58 objects became official discoveries. We planned the runs using six criteria and four servers which focus mostly on faint and poorly observed objects in need of confirmation, follow-up and recovery. We followed 62 faint NEAs within one month after discovery and we recovered 10 faint NEAs having big uncertainties at their second or later opposition. Using the INT we eliminated 4 PHA candidates and VIs. We observed in total 1,286 moving objects and we reported more than 10,000 positions. All data were reduced by the members of our network in a team effort, and reported promptly to the MPC. The positions of the program NEAs were published in 27 MPC and MPEC references and used to improve their orbits. The O-C residuals for known MBAs and program NEAs are smallest for the ESO/MPG and Swope and about four times larger for the INT whose field is more distorted. The incidental survey allowed us to study statistics of the MBA and NEA populations observable today with 1--2m facilities. We calculate preliminary orbits for all unknown objects, classifying them as official discoveries, later identifications and unknown outstanding objects. The orbital elements a, e, i calculated by FIND_ORB software for the official discoveries and later identified objects are very similar with the published elements which take into account longer observational arcs; thus preliminary orbits were used in statistics for the whole unknown dataset. (CONTINUED), Accepted in Planetary and Space Science (Aug 2011)
Published: 2011
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4. Modeling the atmospheric limb emission of CO2 at 4.3 μm in the terrestrial planets

Author: Maya García-Comas, Vittorio Formisano, Miguel Lopez-Valverde, Manuel López-Puertas, Bernd Funke, Gabriella Gilli, Pierre Drossart, Giuseppe Piccioni, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Istituto di Fisica dello Spazio Interplanetario (IFSI), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: biology, Aeronomy, Solar zenith angle, Astronomy, Astronomy and Astrophysics, Venus, Mars Exploration Program, biology.organism_classification, Atmosphere, Space and Planetary Science, Planet, Radiative transfer, Terrestrial planet, Environmental science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The MIPAS instrument on board Envisat, in Earth orbit, the PFS and OMEGA instruments on Mars Express, and VIRTIS on board Venus Express are currently providing a dataset of limb measurements of the CO 2 atmospheric fluorescence emission at 4.3-mum from the upper atmosphere of the three planets. These measurements represent an excellent dataset to perform comparative studies between the terrestrial planets' upper atmospheres, and also to test our theoretical understanding of these emissions. In order to exploit these datasets, we apply a set of non-local thermodynamic equilibrium (non-LTE) models developed at the IAA/CSIC, in Granada, Spain, to a selection of data. In general, the models can explain the main spectral features of the measurements, and also the altitude and solar zenith angle variations. However, the simulations for Mars and Venus give an incorrect ratio of the emissions at two wavelengths, 4.4 and 4.32mum. In order to explain this deficiency, a revision of the most uncertain non-LTE energy transfer parameters has been performed. The quenching rate of nu3 quanta of high-energy CO 2 states by CO 2 itself could reduce the model-data discrepancy if increased by a factor 2-4, still within its current uncertainty range. This factor, however, is subject to the uncertainty in the thermal structure. A number of simulations with the non-LTE models were also used to study and compare the role of radiative transfer in this spectral region in the three terrestrial planets. Sensitivity studies of density and temperature are also presented, and they permit an analysis of how the differences between the planets and between the three instruments affect their sounding capabilities.
Published: 2011
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5. Low-amplitude variations detected by CoRoT in the B8IIIe star HD 175869

Author: M. Auvergne, A. L. Huat, B. de Batz, O. Thizy L. Andrade, Y. Frémat, J. Suso, Eduardo Janot-Pacheco, T. Semaan, Juan Gutiérrez-Soto, R. Garrido, Michele Floquet, R. Samadi, Marcelo Emilio, Coralie Neiner, Juan Fabregat, F. Espinosa Lara, B. Leroy, Anne-Marie Hubert, P. D. Diago, Christophe Martayan, S. Chaintreuil, C. Catala, Eric Michel, Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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)-Centre National de la Recherche Scientifique (CNRS), Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Instituto de Astrofisica de Andalucia, CSIC (IAA), Universitat de València (UV), Observatoire Royal de Belgique (ORB), Departamento de Geociências, Universidade Estadual de Ponta Grossa, Shelyak Instruments, and Departamento de Astronomia Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo
Subjects: Physics, Photosphere, Be star, Astronomy, Astronomy and Astrophysics, Context (language use), Astrophysics, Light curve, Stars, Amplitude, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract: International audience; Context: The origin of the short-term variability in Be stars remains a matter of controversy. Pulsations and rotational modulation are the components of the favored hypothesis. Aims: We present our analysis of CoRoT data of the B8IIIe star HD 175869 observed during the first short run in the center direction (SRC1). Methods: We review both the instrumental effects visible in the CoRoT light curve and the analysis methods used by the CoRoT Be team. We applied these methods to the CoRoT light curve of the star HD 175869. A search for line-profile variations in the spectroscopic data was also performed. We also searched for a magnetic field, by applying the LSD technique to spectropolarimetric data. Results: The light curve exhibits low-amplitude variations of the order of 300 mumag with a double wave shape. A frequency within the range determined for the rotational frequency and 6 of its harmonics are detected. The main frequency and its first harmonic exhibit amplitude variations of a few days. Other significant frequencies of low-amplitude from 25 to a few mumag are also found. The analysis of line profiles from ground-based spectroscopic data does not detect any variation. In addition, no Zeeman signature was found. Conclusions: Inhomogeneities caused by stellar activity in or just above the photosphere are proposed to produce the photometric variability detected by CoRoT in the Be star HD 175869. The hypothesis that non-radial pulsations are the origin of these variations cannot be excluded.
Published: 2009
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6. HD 50844: a new look atδScuti stars from CoRoT space photometry

Author: L. Mantegazza, K. Uytterhoeven, Eric Michel, M. Auvergne, Frédéric Baudin, C. Catala, E. Rodriguez, Ennio Poretti, R. Samadi, Juan Carlos Suárez, Susana Martín-Ruiz, Monica Rainer, M. Alvarez, Annie Baglin, Laure Lefèvre, Emese Plachy, R. Garrido, Péter Pápics, Philippe Mathias, M. Paparó, E. Niemczura, W. Zima, A. Moya, Pedro J. Amado, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astronomical Institute, University of Wroclaw, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Observatorio Astronómico Nacional, Instituto de Astronomía, Universidad Nacional Autónoma de México, Laboratoire Hippolyte Fizeau (FIZEAU), 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), and Konkoly Observatory, Research Center for Astronomy and Earth Sciences
Subjects: Physics, Frequency analysis, Flux, Astronomy, Astronomy and Astrophysics, Context (language use), Astrophysics, Light curve, Spectral line, law.invention, Photometry (optics), Stars, Amplitude, [SDU]Sciences of the Universe [physics], Space and Planetary Science, law, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context: Aims: This work presents the results obtained by CoRoT on HD 50844, the only delta Sct star observed in the CoRoT initial run (57.6 d). The aim of these CoRoT observations was to investigate and characterize for the first time the pulsational behaviour of a delta Sct star, when observed at a level of precision and with a much better duty cycle than from the ground. Methods: The 140 016 datapoints were analysed using independent approaches (SigSpec software and different iterative sine-wave fittings) and several checks performed (splitting of the timeseries in different subsets, investigation of the residual light curves and spectra). A level of 10-5 mag was reached in the amplitude spectra of the CoRoT timeseries. The space monitoring was complemented by ground-based high-resolution spectroscopy, which allowed the mode identification of 30 terms. Results: The frequency analysis of the CoRoT timeseries revealed hundreds of terms in the frequency range 0-30 d-1. All the cross-checks confirmed this new result. The initial guess that delta Sct stars have a very rich frequency content is confirmed. The spectroscopic mode identification gives theoretical support since very high-degree modes (up to l=14) are identified. We also prove that cancellation effects are not sufficient in removing the flux variations associated to these modes at the noise level of the CoRoT measurements. The ground-based observations indicate that HD 50844 is an evolved star that is slightly underabundant in heavy elements, located on the Terminal Age Main Sequence. Probably due to this unfavourable evolutionary status, no clear regular distribution is observed in the frequency set. The predominant term (f_1=6.92 d-1) has been identified as the fundamental radial mode combining ground-based photometric and spectroscopic data. Conclusions
Published: 2009
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7. Stellar population constraints on the dark matter content and origin of ultra-compact dwarf galaxies★

Author: Igor Chilingarian, Gilles Bergond, V. Cayatte, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Shternberg State Institute of Astronomy (SSIA), Laboratoire Univers et Théories (LUTH (UMR_8102)), 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)-Centre National de la Recherche Scientifique (CNRS), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Initial mass function, Stellar mass, Stellar population, Milky Way, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Space and Planetary Science, Globular cluster, Elliptical galaxy, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract: We analyse intermediate-resolution VLT FLAMES/Giraffe spectra of six ultra-compact dwarf (UCD) galaxies in the Fornax cluster. We obtained velocity dispersions and stellar population properties by full spectral fitting against PEGASE.HR models. Objects span a large range of metallicities (-0.95 to -0.23 dex), 4 of them are older than 8 Gyr. Comparison of the stellar and dynamical masses suggests that UCDs have little dark matter at best. For one object, UCD3, the Salpeter initial mass function (IMF) results in the stellar mass significantly exceeding the dynamical one, whereas for the Kroupa IMF the values coincide. Although, this object may have peculiar dynamics or/and stellar populations, the Kroupa IMF seems more realistic. We find that UCDs lie well above the metallicity-luminosity relation of early-type galaxies. The same behaviour is demonstrated by some of the massive Milky Way globular clusters, known to contain composite stellar populations. Our results support two following UCD formation scenarii: (1) tidal stripping of nucleated dwarf elliptical galaxies; (2) formation of tidal superclusters in galaxy mergers. We also discuss some of the alternative channels of the UCD formation binding them to globular clusters., Comment: accepted to MNRAS, 7 pages, 4 figures, 3 tables
Published: 2008
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8. A procedure for modelling asymptotic g-mode pulsators: The case of γ Doradus stars

Author: Andrés Moya, Pedro J. Amado, Marc-Antoine Dupret, Cristina Rodríguez-López, J. C. Suárez, Susana Martín-Ruiz, R. Garrido, E. Rodríguez, A. Grigahcène, Instituto de Astrofisica de Andalucia, CSIC (IAA), Centre de Recherche en Astronomie Astrophysique et Géophysique - Observatoire d'Alger (CRAAG), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Stars, T Tauri star, Space and Planetary Science, Frequency ratio, Mode (statistics), Astrophysics::Solar and Stellar Astrophysics, Applied mathematics, Astronomy and Astrophysics, Astrophysics, Star (graph theory), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Asteroseismology
Abstract: Mode identification is one of the first and main problems we encounter in trying to develop the complete potential of asteroseismology. In the particular case of g-mode pulsators, this is still an unsolved problem, from both the observational and theoretical points of view. Nevertheless, in recent years, some observational and theoretical efforts have been made to find a solution. In this work we use the latest theoretical and computational tools to understand asymptotic g-mode pulsators: 1) the Frequency Ratio Method, and 2) Time Dependent Convection. With these tools, a self-consistent procedure for mode identification and modelling of these g-mode pulsators can be constructed. This procedure is illustrated using observational information available for the γ Doradus star 9Aurigae. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Published: 2008
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9. Fueling the central engine of radio galaxies

Author: Jeremy Lim, Stephane Leon, Santiago García-Burillo, Asunción Fuente, Antonio Usero, Roberto Neri, Francoise Combes, Observatorio Astronomico Nacional, Madrid, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), and Institute of Astronomy and Astrophysics, Academia Sinica
Subjects: Physics, Space and Planetary Science, Radio galaxy, Astrophysics (astro-ph), FOS: Physical sciences, Plateau de Bure Interferometer, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: We report the detection of a massive (M(gas) > 5x10^9 Msun) molecular/dusty disk of 1.4kpc-size fueling the central engine of the Compact Symmetric Object (CSO) 4C31.04 based on high-resolution (0.5''--1.2'') observations done with the IRAM Plateau de Bure interferometer (PdBI). These observations allow for the first time to detect and map the continuum emission from dust at 218GHz in the disk of a CSO. The case for a massive disk is confirmed by the detection of strong HCO+(1--0) line emission and absorption. The molecular gas mass of 4C31.04 is in the range 0.5x10^10--5x10^10Msun. While the distribution and kinematics of the gas correspond roughly to those of a rotating disk, we find evidence of distortions and non-circular motions suggesting that the disk is not in a dynamically relaxed state. We discuss the implications of these results for the general understanding of the evolution of radio galaxies., 5 pages, 3 figures, Accepted (25/04/2007) in A&A Letters
Published: 2007
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10. Chariklo's size, shape and orientation from stellar occultations

Author: Bérard, Diane, Sicardy, Bruno, Assafin, Marcelo, Braga-Ribas, F., Camargo, J. I. B., Vieira Martins, Roberto, Duffard, René, Ortiz, José Luiz, Snodgrass, Colin, Jehin, Emmanuel, Pollock, Joseph T., Colas, François, Dauvergne, Jean-Luc, Lecacheux, Jean, Maquet, Lucie, Sickafoose, Amanda A., Bath, Karl Ludwig, Beisker, Wolfgang, Leiva, Rodrigo, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo, Universidade Federal do Rio de Janeiro, Federal University of Technology (UTFPR/DAFIS) - Parana, Observatório Nacional/MCTI, Instituto de Astrofisica de Andalucia, CSIC (IAA), CEPSAR, The Open University, University of Liège, Physics and Astronomy department, Camosun College, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Atmospheric and Planetary Sciences, MIT, and International Occultation Timing Association, European Section (IOTA/ES)
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Chariklo is the largest Centaur object known to date, and it is surrounded by dense and narrow rings (Braga-Ribas et al. Nature 508, 72, 2014). The size, shape and orientation of the central body are important parameters to better understand the dynamics of the rings.In that context, we have analyzed three stellar occultations by Chariklo and its main ring observed on June 3, 2013, April 29, 2014 and June 28, 2014. Elliptical limb fitting to Chariklo's main body occultation chords has been performed, where we denote a (resp. b) the semi-major (resp. semi-minor) axis of the limb. Preliminary results indicate that Chariklo's limb is elliptical with axes ratio b/a~0.89. We obtain a~133 km and b~119 km, providing an equivalent radius of Requiv=&surd;(ab)~126 km. The rms dispersion of the fit, about 4 km, is compatible with local topographic features on a small icy body. For comparison, an equivalent radius of Requiv= 119±5 km, based on thermal data, is given by Fornasier et al, AA 518, L11, 2014, while Duffard et al. AA 568, A79, 2014 estimate a= 122 km and b= 117 km.Our results are obtained under the simplifying assumption that the main ring is circular and that its center coincides with that of Chariklo. Caveats and error bars will be discussed, and dynamical implications will be presented. In particular, rough estimations of the ring apsidal precession rates will be given, as well as constraints on Chariklo's density.
Published: 2015

11. Pluto's atmosphere from stellar occultations in 2012 and 2013

Author: A. Dias-Oliveira, B. Sicardy, E. Lellouch, R. Vieira-Martins, M. Assafin, J. I. B. Camargo, F. Braga-Ribas, A. R. Gomes-Júnior, G. Benedetti-Rossi, F. Colas, A. Decock, A. Doressoundiram, C. Dumas, M. Emilio, J. Fabrega Polleri, R. Gil-Hutton, M. Gillon, J. H. Girard, G. K. T. Hau, V. D. Ivanov, E. Jehin, J. Lecacheux, R. Leiva, C. Lopez-Sisterna, L. Mancini, J. Manfroid, A. Maury, E. Meza, N. Morales, L. Nagy, C. Opitom, J. L. Ortiz, J. Pollock, F. Roques, C. Snodgrass, J. F. Soulier, A. Thirouin, L. Vanzi, T. Widemann, D. E. Reichart, A. P. LaCluyze, J. B. Haislip, K. M. Ivarsen, M. Dominik, U. Jørgensen, J. Skottfelt, Observatório Nacional/MCTI, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo, Universidade Federal do Rio de Janeiro, UTFPR, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, ESO, UEPG, Observatorio Panemno, CASLEO-CONICET, Universite de Liege, PUC, Universidade Nacional de San Juan, Max-Planck-Institut für Astronomie (MPIA), S.P.A.C.E, Instituto de Astrofisica de Andalucia, CSIC (IAA), Appalachian State University, CEPSAR, The Open University, Association T60, Observatoire Midi-Pyrénées, Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Lowell Observatory, Flagstaff, University of North Carolina, School of Chemistry, University of St Andrews, University of Copenhagen, Observatorio Nacional [Rio de Janeiro], Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Observatório Nacional/MCT, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Universidad Nacional de San Juan (UNSJ), Arctic and Antarctic Research Institute (AARI), Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet), European Southern Observatory (ESO), Southwest Research Institute [Boulder] (SwRI), Centre de Nanosciences et Nanotechnologies (C2N (UMR_9001)), Université Paris-Sud - Paris 11 (UP11)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Department of Physics and Astronomy [Boone], University of North Carolina System (UNC)-University of North Carolina System (UNC), School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), Lowell Observatory [Flagstaff], Dynamiques patrimoniales et culturelles (DYPAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universidade Federal do Rio de Janeiro (UFRJ), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Universidad Nacional de San Juan [Argentine] (UNSJ), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), The Royal Society, and University of St Andrews. School of Physics and Astronomy
Subjects: 010504 meteorology & atmospheric sciences, NDAS, FOS: Physical sciences, Astrophysics, 01 natural sciences, Mesosphere, Troposphere, Atmosphere, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, QB Astronomy, observational [Methods], data analysis [Methods], 010303 astronomy & astrophysics, Stratosphere, physical evolution [Planets and satellites], QC, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], photometric [Techniques], Center (category theory), Astronomy and Astrophysics, Radius, Pluto, Temperature gradient, QC Physics, 13. Climate action, Space and Planetary Science, terrestrial planets [Planets and satellites], atmospheres [Planets and satellites], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We analyze two multi-chord stellar occultations by Pluto observed on July 18th, 2012 and May 4th, 2013, and monitored respectively from five and six sites. They provide a total of fifteen light-curves, twelve of them being used for a simultaneous fit that uses a unique temperature profile, assuming a clear (no-haze) and pure N_2 atmosphere, but allowing for a possible pressure variation between the two dates. We find a solution that fits satisfactorily (i.e. within the noise level) all the twelve light-curves, providing atmospheric constraints between ~1,190 km (pressure ~ 11 \mubar) and ~ 1,450 km (pressure ~0.1 \mubar) from Pluto's center. Our main results are: (1) the best-fitting temperature profile shows a stratosphere with strong positive gradient between 1,190 km (at 36 K, 11 \mubar) and r = 1,215 km (6.0 \mubar), where a temperature maximum of 110 K is reached; above it is a mesosphere with negative thermal gradient of -0.2 K/km up to ~ 1,390 km (0.25 \mubar), where, the mesosphere connects itself to a more isothermal upper branch around 81 K; (2) the pressure shows a small (6 %) but significant increase (6-\sigma level) between the two dates; (3) without troposphere, Pluto's radius is found to be R_P = 1,190 +/- 5km. Allowing for a troposphere, R_P is constrained to lie between 1,168 and 1,195 km; (4) the currently measured CO abundance is too small to explain the mesospheric negative thermal gradient. Cooling by HCN is possible, but only if this species is largely saturated; Alternative explanations like zonal winds or vertical compositional variations of the atmosphere are unable to explain the observed mesospheric trend., Comment: 41 pages, 13 figures, 4 tables
Published: 2015
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12. The asymptotic representation of higher-order g$\mathsf{^+}$-modes in stars with a convective core

Author: Paul Smeyers, Andrés Moya, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Surface (mathematics), Asymptotic analysis, Astronomy and Astrophysics, Astrophysics, Radiation zone, Displacement (vector), Stars, Classical mechanics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Circular symmetry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mathematical physics, Envelope (waves)
Abstract: International audience; Aims:A first-order asymptotic representation of higher-order non-radial g^+-modes in spherically symmetric stars with a convective core is constructed from the full fourth-order system of governing equations. Stars are considered that, besides their convective core, also contain a radiative envelope, or both an intermediate radiative zone and a convective envelope. At the same time, the earlier asymptotic theory of Willems et al. (1997, A&A, 318, 99) relative to stars consisting of a convective core and a radiative envelope is made more transparent. Methods: As in the asymptotic theory of Smeyers (2006, A&A, 451, 223) for low-degree, higher-order p-modes, two-variable expansion procedures and boundary-layer theory are applied to the fourth-order system of differential equations established by Pekeris (1938, ApJ, 88, 189). Results: Eigenfrequency equations are derived in terms of the radial order n of the g^+-mode. The first n - 1 nodes of the radial component of the Lagrangian displacement coincide with the n - 1 nodes of the divergence of the Lagrangian displacement, and are situated in the radiative envelope or in the intermediate radiative zone according to the type of star considered. The radial displacement displays an nth node near the surface. In stars containing an intermediate radiative zone and a convective envelope, the nth node is situated in the envelope. Conclusions: .As well as for higher-order p-modes of spherically symmetric stars, the divergence of the Lagrangian displacement plays a basic role in the development of the asymptotic theory.
Published: 2006
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13. On the discovery of CO nighttime emissions on Titan by Cassini/VIMS: Derived stratospheric abundances and geological implications

Author: Kevin H. Baines, Bonnie J. Buratti, Miguel Lopez-Valverde, Robert H. Brown, Philip D. Nicholson, Thomas W. Momary, Roger N. Clark, Sushil K. Atreya, Christophe Sotin, Pierre Drossart, Jet Propulsion Laboratory, California Institute of Technology (JPL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, US Geological Survey, Denver, and Department of Astronomy, Cornell University
Subjects: Physics, 010504 meteorology & atmospheric sciences, Airglow, Astronomy and Astrophysics, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Atmosphere, symbols.namesake, 13. Climate action, Space and Planetary Science, Stratopause, Atmospheric chemistry, 0103 physical sciences, Mixing ratio, symbols, Atmosphere of Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), 010303 astronomy & astrophysics, Stratosphere, 0105 earth and related environmental sciences
Abstract: International audience; We present a quantitative analysis of CO thermal emissions discovered on the nightside of Titan by Baines et al. [2005. The atmospheres of Saturn and Titan in the near-infrared: First results of Cassini/VIMS. Earth, Moon, and Planets, 96, 119-147]. in Cassini/VIMS spectral imagery. We identify these emission features as the P and R branches of the 1-0 vibrational band of carbon monoxide (CO) near 4.65 mum. For CH 3D, the prominent Q branch of the nu 2 fundamental band of CH 3D near 4.55 mum is apparent. CO 2 emissions from the strong v3 vibrational band are virtually absent, indicating a CO 2 abundance several orders of magnitude less than CO, in agreement with previous investigations. Analysis of CO emission spectra obtained over a variety of altitudes on Titan's nightside limb indicates that the stratospheric abundance of CO is 32±15 ppm, and together with other recent determinations, suggests a vertical distribution of CO nearly constant at this value from the surface throughout the troposphere to at least the stratopause near 300 km altitude. The corresponding total atmospheric content of CO in Titan is ˜2.9±1.5×10 14 kg. Given the long lifetime of CO in the oxygen-poor Titan atmosphere (˜0.5-1.0 Gyr), we find a mean CO atmospheric production rate of 6±3×10 5 kg yr -1. Given the lack of primordial heavy noble gases observed by Huygens [Niemann et al., 2005. The abundances of constituents of Titan's atmosphere from the GCMS on the Huygens probe. Nature, 438, 779-784], the primary source of atmospheric CO is likely surface emissions. The implied CO/CH 4 mixing ratio of near-surface material is 1.8±0.9×10 -4, based on an average methane surface emission rate over the past 0.5 Gyr of 1.3×10 -13 gm cm -2 s -1 as required to balance hydrocarbon haze production via methane photolysis [Wilson and Atreya, 2004. Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere. J. Geophys. Res. 109, E06002 Doi:10.1029/2003JE002181]. This low CO/CH 4 ratio is much lower than expected for the sub-nebular formation region of Titan and supports the hypothesis [e.g., Atreya et al., 2005. Methane on Titan: photochemical-meteorological-hydrogeochemical cycle. Bull. Am. Astron. Soc. 37, 735] that the conversion of primordial CO and other carbon-bearing materials into CH 4-enriched clathrate-hydrates occurs within the deep interior of Titan via the release of hydrogen through the serpentinization process followed by Fischer-Tropsch catalysis. The time-averaged predicted emission rate of methane-rich surface materials is ˜0.02 km 3 yr -1, a value significantly lower than the rate of silicate lava production for the Earth and Venus, but nonetheless indicative of significant active geological processes reshaping the surface of Titan.
Published: 2006
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14. A comprehensive asteroseismic modelling of the high-amplitude δ Scuti star RV Arietis

Author: A. Moya, Juan Carlos Suárez, Ricard Casas, R. Garrido, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Oscillations, Rotation, Variable stars, Overtone, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), Fundamental parameters, Astrophysics::Solar and Stellar Astrophysics, Adiabatic process, Astrophysics::Galaxy Astrophysics, Physics, High amplitude, Oscillation, Astrophysics (astro-ph), Interiors, Astrophysics::Instrumentation and Methods for Astrophysics, Delta Scuti, RV Arietis, Mode (statistics), Astronomy and Astrophysics, Effective temperature, Stars, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Reproduced with permission from Astronomy & Astrophysics, © ESO., We present a comprehensive asteroseismic study of the double-mode high-amplitude $\delta$ Scuti star HD 187642 ( RV Ari ). The modelling includes some of the most recent techniques: 1) effects of rotation on both equilibrium models and adiabatic oscillation spectrum, 2) non-adiabatic study of radial and non-radial modes, 3) relationship between the fundamental radial mode and the first overtone in the framework of Petersen diagrams. The analysis reveals that two of the observed frequencies are very probably identified as the fundamental and first overtone radial modes. Analysis of the colour index variations, together with theoretical non-adiabatic calculations, points to models in the range of [7065, 7245] K in effective temperature and of [1190, 1270] Myr in stellar age. These values were found to be compatible with those obtained using the three other asteroseismic techniques., This work was partially financed by the Spanish "Plan Nacional del Espacio'', under project ESP2004-03855-C03-01. J.C.S. acknowledges the financial support of the European Marie Curie action MERG-CT-2004-513610 and the Spanish "Consejería de Innovación, Ciencia y Empresa" from the "Junta de Andalucía" local government.
Published: 2006
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15. The frequency ratio method and the new multiperiodicγ Doradus star HD 218427

Author: E. Rodríguez, M. J. Lopez-Gonzalez, Pedro J. Amado, E. Poretti, A. Grigahcène, Andrés Moya, V. Costa, J. C. Suárez, M. A. Dupret, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, INAF-Osservatorio Astronomico di Brera (INAF-OAB), and Centre de Recherche en Astronomie Astrophysique et Géophysique - Observatoire d'Alger (CRAAG)
Subjects: Physics, Frequency analysis, Astronomy and Astrophysics, Astrophysics, Star (graph theory), Lambda, Quantum number, Instability, law.invention, Stars, Space and Planetary Science, law, Excited state, Astrophysics::Solar and Stellar Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Multiplet, Astrophysics::Galaxy Astrophysics
Abstract: International audience; Oscillations of gamma Dor-type were discovered in the star HD 218427 through simultaneous uvby photometric observations carried out in the year 2003. A few Hbeta-Crawford measurements were also collected for calibration purposes and they locate this star well inside the gamma Dor instability region. We find HD 218427 to be deficient in metals, similar to other well-defined gamma Dor stars, and discuss the possibility that it has a lambda Boo nature. We carried out frequency analysis for different filters, including the combined "vby" filter, and five frequencies were found as significant with periods ranging between 0.3 and 0.8 days. The recently-developed frequency ratio method is used in order to identify the excited modes. The results are consistent with an l=2 identification for all the modes and with high radial quantum numbers (n˜40) for the three main observed periodicities. The possibility of multiplet structures is also discussed. However, no consistency is found when using the time-dependent convection treatment to discriminate modes. This disagreement can be due to the large rotation velocity taking place in HD 218427 and, consequently, the significant coupling between the modes.
Published: 2006
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16. Carbon monoxide fluorescence from Titan's atmosphere

Author: Miguel Lopez-Valverde, Emmanuel Lellouch, Athena Coustenis, Instituto de Astrofisica de Andalucia, CSIC (IAA), Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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: Physics, Meteorology, Spectrometer, Astronomy and Astrophysics, Atmospheric sciences, Troposphere, symbols.namesake, chemistry.chemical_compound, chemistry, Space and Planetary Science, symbols, Mixing ratio, Radiative transfer, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Stratosphere, Carbon monoxide
Abstract: International audience; We report on the discovery of emissions due to carbon monoxide from Titan's atmosphere, from mid-infrared observations with the ISAAC spectrometer at the Very Large Telescope and covering the 4.50-4.85 mum range. We detected about 45 emission lines coinciding with CO ro-vibrational lines, including CO(1-0) (P18 to R11) and CO(2-1) (P11 to R11). We show that these emissions cannot be generated thermally but occur in non-LTE conditions, due to radiative de-excitation from the v=1 and v=2 CO levels after excitation at 4.7 and 2.3 mum by solar radiation. A complete fluorescence model is then developed, allowing to compute the state populations of the two most abundant CO isotopes and N 2(1). It includes absorption by CO and CH 4, and vibrational-thermal and vibrational-vibrational collisional exchanges with CO, N 2, CH 4, and H 2. Emerging radiances at the top of the atmosphere are evaluated with a line-by-line code and compared to observations. Contribution functions show that the CO emissions sound Titan's stratosphere: while the (1-0) lines generally probe two layers, located respectively at 100-250 km and 300-550 km, the (2-1) lines are sensitive to the intermediate layer at 150-300 km. A sensitivity study is performed to establish the effect of the main model parameters (temperature profile, collisional scenario, and CO stratospheric abundance) on the results. Models reproduce the essential structure of the observed emissions. The (1-0) fundamental band is generally well fit with a nominal CO mixing ratio of 32 ppm---as inferred in the troposphere from observations at 4.80-5.10 mum (Lellouch et al., 2003, Icarus 162, 126-143). However, this band is only weakly dependent on the CO abundance, and given temperature and collisional scenario uncertainties, it constrains the CO stratospheric mixing ratio only to within a factor of ˜3. In addition, the nominal model with 32 ppm CO underestimates the first hot (2-1) transition by approximately a factor of 2. This discrepancy can be resolved by a combined adjustment of collisional rates and an increased CO stratospheric ratio of 60 ppm, consistent with the determination of Gurwell and Muhleman (2000, Icarus 145, 653-656). In contrast, the CO vertical profile suggested by Hidayat et al. (1998, Icarus 133, 109-133), strongly depleted above 200 km, cannot match the data for any realistic collisional scenario, and is therefore not supported by our results.
Published: 2005
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17. Molecular and ionized gas in the tidal tail in Stephan's Quintet

Author: Stephane Leon, Elias Brinks, Jonathan Braine, Vassilis Charmandaris, Pierre-Alain Duc, Ute Lisenfeld, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE), Department of Astronomy, Cornell University, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)
Subjects: Intergalactic star, Interactions, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Clusters, Astrophysics::Solar and Stellar Astrophysics, Tidal tail, ISM, Astrophysics::Galaxy Astrophysics, Intergalactic medium, Dwarf galaxy, Physics, Spiral galaxy, Star formation, Astrophysics (astro-ph), Astronomy and Astrophysics, Molecules, Galaxies, Galaxy, Dust lane, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Stephan's Quintet, Intergalactic travel, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We have mapped with the IRAM interferometer at Plateau de Bure (PdBI) the 12CO emission towards intergalactic star forming regions located in the tidal tail stemming from NGC7319, in the Stephan's Quintet compact group of galaxies. The 13CO emission of the same region was observed with the IRAM 30m telescope and optical spectroscopy of several HII regions in the area were obtained with the Calar Alto 3.5m telescope. We recovered with the interferometer about 50% of the CO(1-0) total emission that had been earlier measured with single dish observations. We find two main areas of CO emission: (i) an elongated region towards the area known as SQ B where a Tidal Dwarf Galaxy could currently be forming (ii) a barely resolved area at the tip of the optical tidal arm. Both regions follow dust lanes visible on HST images and their CO peak coincides spatially exactly with the maximum of the Halpha line emission. In SQ B, there is furthermore very good kinematical agreement between the CO, Halpha and HI components. We conclude from these coincidences that the gaseous matter found in quantities in the area is physically associated to the optical tidal tail and thus that the intergalactic atomic hydrogen there was expelled from NGC7319. Furthermore, the relatively high oxygen abundances (about solar) estimated from the optical spectra of the HII regions imply that the gas feeding the star formation originated from the inner regions of the parent galaxy. In SQ B, we derive from different tracers a star formation rate of 0.5 \msun/yr. The inferred molecular gas consumption time of 0.5 Gyr lies in the range of values found for spiral and starburst galaxies. On the other hand, the ratio of 12CO/13CO>25 is much higher than the values found in disks of spiral galaxies. A relatively low opacity for the 12CO gas is the most likely reason., Accepted by A&A, 10 pages, 7 figures, a version with high resolution figures can be obtained from http://www.ugr.es/~ute/1330.pdf
Published: 2004
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18. Non-confirmation of reported $\ion{H}{I}$ clouds without optical counterparts in the Hercules cluster

Author: P. Papaderos, C. Balkowski, José M. Vílchez, V. Cayatte, Trinh X. Thuan, John M. Dickey, W. van Driel, H. Hernández, Karen O'Neil, Pierre-Alain Duc, Jorge Iglesias-Páramo, Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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)-Centre National de la Recherche Scientifique (CNRS), Physique des Galaxies et Cosmologie, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Arecibo Observatory, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Astronomy, University of Minnesota, 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), Sternwarte Weinheim, Instituto de Astrofisica de Andalucia, CSIC (IAA), and Astronomy Department, University of Virginia, Charlottesville
Subjects: Physics, Gregorian telescope, Galactic astronomy, Continuum (measurement), 010308 nuclear & particles physics, media_common.quotation_subject, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, general, clusters, individual, Hercules cluster, galaxies, ISM, radio lines, 01 natural sciences, law.invention, Space and Planetary Science, law, Sky, 0103 physical sciences, Surface brightness, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, media_common
Abstract: 21 cm HI line observations were made with the Arecibo Gregorian telescope of 9 HI clouds in the Hercules Cluster which were reported as tenative detections in a VLA HI study of the cluster (Dickey 1997) and for which our deep CCD imaging failed to find any optical counterparts. No sensitive observations could be made of one of these (sw-174) due to the presence of a close-by strong continuum source. The other 8 tentative HI detections were not reconfirmed by the Arecibo HI measurements. The CCD images did reveal faint, low surface brightness counterparts near the centres of two other VLA HI sources invisible on the Palomar Sky Survey, sw-103 and sw-194., Comment: 7 pages, accepted for Astronomy and Astrophysics on 8 Nov. 2002; new references added on 23 Dec. 2002
Published: 2003
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19. Galaxy clusters in the SDSS Stripe 82 based on photometric redshifts

Author: C. Adami, S. Maurogordato, Melville P. Ulmer, Ali Takey, Florence Durret, Nicolas Martinet, N. Scepi, J. Hao, Isabel Márquez, T. Sauvaget, E. Bertin, National Science Foundation (US), Department of Energy (US), University of Arizona, Brookhaven National Laboratory (US), Carnegie Mellon University, University of Florida, Harvard University, Instituto de Astrofísica de Canarias, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for extraterrestrial Physics, New Mexico State University, New York University, The Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, Yale University, Ministerio de Economía y Competitividad (España), Junta de Andalucía, Alfred P. Sloan Foundation, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (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), Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Instituto de Astrofisica de Andalucia, CSIC (IAA), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, Northwestern University, Evanston, École normale supérieure - Cachan (ENS Cachan), National Research Institute of Astronomy and Geophysics (NRIAG), 11421 Helwan, Cairo, Egypt, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Tsinghua University [Beijing] (THU), Institut Régional de Médecine Physique et de Réadaptation Louis Pierquin [Nancy] (IRR Louis Pierquin), 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NWU, Dearborn Observatory (NWU), Northwestern University Department of Physics and Astronomy, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), 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, and 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)
Subjects: Galaxies: fundamental parameters, Cosmology and Nongalactic Astrophysics (astro-ph.CO), luminosity function, mass function [Galaxies], FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, clusters: general [Galaxies], 01 natural sciences, Cosmology, Luminosity, 0103 physical sciences, Cluster (physics), 010303 astronomy & astrophysics, Galaxy cluster, Astrophysics::Galaxy Astrophysics, Photometric redshift, Physics, 010308 nuclear & particles physics, 4. Education, Galaxies: luminosity function, mass function, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), fundamental parameters [Galaxies], Galaxies: clusters: general, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: © ESO 2015. Context. The discovery of new galaxy clusters is important for two reasons. First, clusters are interesting per se, since their detailed analysis allows us to understand how galaxies form and evolve in various environments and second, they play an important part in cosmology because their number as a function of redshift gives constraints on cosmological parameters. Aims. We have searched for galaxy clusters in the Stripe 82 region of the Sloan Digital Sky Survey, and analysed various properties of the cluster galaxies. Methods. Based on a recent photometric redshift (hereafter photo-z) galaxy catalogue, we built a cluster catalogue by applying the Adami & MAzure Cluster FInder (AMACFI). Extensive tests were made to fine-tune the AMACFI parameters and make the cluster detection as reliable as possible. The same method was applied to the Millennium simulation to estimate our detection efficiency and the approximate masses of the detected clusters. Considering all the cluster galaxies (i.e. within a 1 Mpc radius of the cluster to which they belong and with a photo-z diering by less than ±0.05 from that of the cluster), we stacked clusters in various redshift bins to derive colour-magnitude diagrams and galaxy luminosity functions (GLFs). For each galaxy brighter than Mr < - 19.0, we computed the disk and spheroid components by applying SExtractor, and by stacking clusters we determined how the disk-to-spheroid flux ratio varies with cluster redshift and mass. Results. We detected 3663 clusters in the redshift range 0.15 ≤ z ≤ 0.70, with estimated mean masses between ∼1013 and a few 1014 M⊙. We cross-matched our catalogue of candidate clusters with various catalogues extracted from optical and/or X-ray data. The percentages of redetected clusters are at most 40% because in all cases we detect relatively massive clusters, while other authors detect less massive structures. By stacking the cluster galaxies in various redshift bins, we find a clear red sequence in the (ǵ - ŕ) versus ŕ colour-magnitude diagrams, and the GLFs are typical of clusters, though with a possible contamination from field galaxies. The morphological analysis of the cluster galaxies shows that the fraction of late-type to early-type galaxies shows an increase with redshift (particularly in 9σ clusters) and a decrease with detection level, i.e. cluster mass. Conclusions. From the properties of the cluster galaxies, the majority of the candidate clusters detected here seem to be real clusters with typical cluster properties., F.D. acknowledges long-term support from CNES. I.M. acknowledges financial support from the Spanish grants AYA2010-15169 and AYA2013-42227-P and from the Junta de Andalucia through TIC-114 and the Excellence Project P08-TIC-03531. A.T. acknowledges the support and the hospitality of IAP/CNRS for two one month visits. We are grateful to Andrea Biviano for giving us his IDL program to fit GLFs with a Schechter function and to Alberto Cappi for discussions. We thank the six high school students M.A. Garcia Valverde, B. Hernandez Ramos, J. Leon Lovell, L. Martinez Sanchez de Lara, J. Rodriguez Zamorano and L. Vallecillos Azor for their careful eye classification of about 1000 galaxies. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University.
Published: 2015
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20. Dense and narrow rings around the Centaur object (10199) Chariklo

Author: Sicardy, Bruno, Braga-Ribas, Felipe, Ortiz, Jose Luis, Vieira-Martins, Roberto, Colas, Francois, Duffard, Rene, Camargo, Julio I., Desmars, Josselin, Gulbis, Amanda, Assafin, Marcelo, Maquet, Lucie, Beisker, Wolfgang, Benedetti-Rossi, Gustavo, Vachier, Frederic, Dumas, Christophe, Valentin Ivanov, Renner, Stefan, Bath, Karl-Ludwig, Klotz, Alain, Pollock, Joseph T., Lecacheux, Jean, Dauvergne, Jean-Luc, Peyrot, Andre, Teng, Jean-Paul, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Observatório Nacional/MCTI, Instituto de Astrofisica de Andalucia, CSIC (IAA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatório do Valongo, Universidade Federal do Rio de Janeiro, International Occultation Timing Association, European Section (IOTA/ES), European Southern Observatory, Santiago, Chile, University of Heidelberg, Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, Appalachian State University, Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Association T60, Observatoire Midi-Pyrénées, Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; A stellar occultation observed on June 3, 2013 (Braga-Ribas et al., Nature 508, 72, 2014) revealed the unexpected presence of two dense rings around (10199) Chariklo, the largest Centaur object known to date with a radius of 119±5 km (Fornasier et al. A&A 2014, in press). The two rings (called respectively C1R and C2R hereby) have orbital radii a_C1R= 390.6±3.3 km and a_C2R= 404.8±3.3 km (1-sigma limits), and typical average optical depths of tau_C1R= 0.4 and tau_C2R= 0.06. They are separated by a gap of about 9 km with optical depth less than 0.004.The presence of those two rings was confirmed during four stellar occultations observed in 2014, on February 16 (Chile), March 16 (Thailand), April 29 (Southern Africa) and June 28 (Southern Africa).The occultation events imply a J2000 pole position of alpha= 151.25±0.50 and delta= 41.48±0.22 deg. The rings' changing geometry explains the long term variations of Chariklo's absolute magnitude and the spectral changes observed between 1997 and 2013. They imply a reflectance I/F of about 0.07 for C1R, and show that it contains about 20% of water ice, the latter remaining undetected on Chariklo's surface (Duffard et aL A&A 2014, in press).The April 29, 2014 occultation reveals a W-shaped structure for C1R, with the densest parts reaching an apparent optical depth of about 2. The width of C1R exhibits variations that are compatible with a m=1 mode, its value varying between ~5.5 and ~7.1 km over the full 360 degrees longitude range. The width of C2R is less constrained and lies between 2 and 4 km.This is the first ring system ever observed that does not pertain to a giant planet. The existence of such a system raises several questions as to the origin and evolution of rings around such a small object. This discovery also suggests that rings may be a more frequent feature than previously thought, in particular around small bodies.Possible models for the ring formation will be proposed. They can be classified into collisional scenarios that disrupted an impactor or a pre-existing satellite, tidal disruption of an inward-migrating satellite, or more exotic models in which material produced by a cometary activity of Chariklo was sent in orbit around the body.
Published: 2014

21. Lessons learned from stellar occultations by Trans-Neptunian Objects and prospects for the future

Author: Ortiz, José Luiz, Sicardy, Bruno, Braga-Ribas, F., Morales, Nicolas, Duffard, René, Santos-Sanz, Pablo, Vieira Martins, Roberto, Camargo, J. I. B., Assafin, Marcelo, Roques, Françoise, Widemann, Thomas, Lecacheux, Jean, Colas, François, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Observatório Nacional/MCTI, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Groupe Astrométrie et Planétologie (GAP), and Observatório do Valongo, Universidade Federal do Rio de Janeiro
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The best way to derive physical properties of solar system bodies is to send spacecraft to observe them. Probably the second best means to learn about important physical properties of solar system objects is through stellar occultations. Since October 2009, when the first stellar occultation by a Trans- Neptunian Object other than Pluto was recorded, around seventeen more occultations by Trans- Neptunian Objects have been detected, thanks to the efforts of several teams. Due to the complications of accurately predicting and observing these events, most of the successes have been achieved by an international collaboration of three main teams that coordinate different important aspects, but there have also been other successes in the field. Nevertheless, most of the successes involved large groups of researchers and even amateurs. Here we present a preliminary and brief summary of some of the results obtained thus far as well as a summary on some of the lessons learned to improve the rate of success. A key issue is involving large groups of observers once an accurate prediction has been made.
Published: 2014

22. Spin-induced mass loss from rubble piles and the formation of asteroid satellites and pairs

Author: Tanga, P., Campo Bagatin, A., Thirouin, A., Alberto Cellino, Comito, C., Ortiz, J., Richardson, D., Hestroffer, D., Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Departamento de Física, ISTS, Instituto de Astrofisica de Andalucia, CSIC (IAA), INAF/Osservatorio Astronomico di Torino, Department of Astronomy, University of Maryland, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Muinonen, K., Penttilä, A., Granvik, M., Virkki, Fedorets, G., Wilkman, O., Kohout, and T.
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Non-gravitational effects may change the angular momentum of asteroids up to a few tens of km in size to the point that rotational stability is lost at high spin rates. Once instability is initiated, mass loss may happen and potentially create satellites or dynamically detached components (pairs). We have studied this problem by means of numerical simulations and investigated the production of secondary objects of different sizes by direct splitting of the parent body under the assumption of a low internal angle of friction.
Published: 2014

23. HD 172189, a Cluster Member Binary System with a δ Scuti Component in the Field of View of COROT

Author: Juan Carlos Suárez, Ennio Poretti, Andrés Moya, Ignasi Ribas, Pedro J. Amado, Armando Arellano Ferro, Susana Martín-Ruiz, European Southern Observatory (ESO), Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astronomia, Universidad Nacional Autonomica de Mexico, Institut dEstudis Espacials de Catalunya/CSIC, and INAF-Osservatorio Astronomico di Brera (INAF-OAB)
Subjects: Physics, Frequency analysis, Field (physics), Astronomy, Binary number, Astronomy and Astrophysics, Astrophysics, Light curve, Spectral line, law.invention, Space and Planetary Science, law, Cluster (physics), Binary system, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Open cluster
Abstract: International audience; Photometric and spectroscopic results for the star HD 172189, member of the open cluster IC 4756 in the summer field of the space mission COROT, are presented. From photometric observations in the Strömgren system carried out at various epochs, its binary nature as well as the presence of a delta Scuti-type pulsating component have been discovered. The frequency analysis of the whole dataset confirms a dominant frequency of 19.5974 c d-1 with a maximum amplitude near 0.02 mag plus other frequencies in the range 18 20 c d-1. A preliminary orbital solution from the light curve and from four FEROS spectra reveals two similar components of around 1.5 M &sun; orbiting with a period of 5.702 d.
Published: 2006
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24. New light on gamma-ray burst host galaxies with Herschel

Author: Silvia Piranomonte, D. Le Borgne, Simone Bianchi, Sylvio Klose, Eliana Palazzi, Jochen Greiner, Elena Pian, Stefano Covino, D. Gotz, Leslie K. Hunt, Sandra Savaglio, E. Le Floc'h, Andrea Rossi, P. Ferrero, S. Berta, Patricia Schady, S. Basa, Michał J. Michałowski, S. D. Vergani, Valerio D'Elia, INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy, INAF - IASF Bologna, via Gobetti 101, 40129, Bologna, Italy, Sterrenkundig Observatorium, Universiteit Gent, Max-Planck-Institut fur Extraterrestrische Physik, Giessenbachstrase, 85748, Garching bei Munchen, Germany, 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), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Agenzia Spaziale Italiana (ASI), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Türinger Landessternwarte Tautenburg, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Roma (INAF-OAR), Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: submillimeter: galaxies, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Infrared, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: high-redshift, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, Physics, COSMIC cancer database, extinction, Spectral density, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Wavelength, Orders of magnitude (time), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), galaxies: star formation, dust, Astrophysics::Earth and Planetary Astrophysics, Gamma-ray burst, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], galaxies: ISM, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Until recently, dust emission has been detected in very few host galaxies of gamma-ray bursts (GRBHs). With Herschel, we have now observed 17 GRBHs up to redshift z~3 and detected seven of them at infrared (IR) wavelengths. This relatively high detection rate (41%) may be due to the composition of our sample which at a median redshift of 1.1 is dominated by the hosts of dark GRBs. Although the numbers are small, statistics suggest that dark GRBs are more likely to be detected in the IR than their optically-bright counterparts. Combining our IR data with optical, near-infrared, and radio data from our own datasets and from the literature, we have constructed spectral energy distributions (SEDs) which span up to 6 orders of magnitude in wavelength. By fitting the SEDs, we have obtained stellar masses, dust masses, star-formation rate (SFR), and extinctions for our sample galaxies. We find that GRBHs are galaxies that tend to have a high specfic SFR (sSFR), and like other star-forming galaxies, their ratios of dust-to-stellar mass are well correlated with sSFR. We incorporate our Herschel sample into a larger compilation of GRBHs, and compare this combined sample to SFR-weighted median stellar masses of the widest, deepest galaxy survey to date. This is done in order to establish whether or not GRBs can be used as an unbiased tracer of cosmic comoving SFR density (SFRD) in the universe. In contrast with previous results, this comparison shows that GRBHs are medium-sized galaxies with relatively high sSFRs; stellar masses and sSFRs of GRBHs as a function of redshift are similar to what is expected for star-forming galaxy populations at similar redshifts. We conclude that there is no strong evidence that GRBs are biased tracers of SFRD; thus they should be able to reliably probe the SFRD to early epochs., 18 pages, 9 figures, accepted for publication in A&A. Revised to include Fig. 6, mistakenly omitted in original
Published: 2014
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25. 'TNOs are Cool': A survey of the trans-Neptunian region. XI. A Herschel-PACS view of 16 Centaurs

Author: T. G. Mueller, Cs. Kiss, Esa Vilenius, Nuno Peixinho, E. Lellouch, Noemi Pinilla-Alonso, Michael Mueller, J. L. Ortiz, A. Delsanti, J. A. Stansberry, A. Pal, David Trilling, Pablo Santos-Sanz, S. Fornasier, Rene Duffard, Michael Mommert, Instituto de Astrofisica de Andalucia, CSIC (IAA), Max-Planck-Institut fur extraterrestrische Physik, Postfach 1312, Giessenbachstr., 85741, Garching, Germany, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Konkoly Thege 15-17, 1121, Budapest, Hungary, SRON Netherlands Institute for Space Research, Space Telescope Science Institute (STScI), 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), Unidad de Astronomia, Facultad de Ciencias Basicas, Universidad de Antofagasta, and Department of Physics and Astronomy, Northern Arizona University, Flagstaff
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Mean diameter, Physics, Orbital elements, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Centaur, Photometry (optics), 13. Climate action, Space and Planetary Science, astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Monochromatic color, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, Data reduction
Abstract: Centaurs are the transitional population between trans-Neptunian objects (TNOs) and Jupiter-family comets. For this reason it is possible to access the smaller ones, which is more difficult to do with the TNO population. The goal of this work is to characterize a set of 16 Centaurs in terms of their size, albedo, and thermal properties. We study the correlations, for a more extended sample obtained from the literature, of diameter, albedo, orbital parameters, and spectral slopes. We performed three-band photometric observations using Herschel-PACS and used a consistent method for the data reduction and aperture photometry of this sample to obtain monochromatic flux densities at 70, 100, and 160 $��$m. Additionally, we used Spitzer-MIPS flux densities at 24 and 70 $��$m when available. We also included in our Centaur sample scattered disk objects (SDOs), a dynamical family of TNOS, using results previously published by our team, and some Centaurs observed only with the Spitzer/MIPS instrument. We have determined new radiometric sizes and albedos of 16 Centaurs. The first conclusion is that the albedos of Centaur objects are not correlated with their orbital parameters. Similarly, there is no correlation between diameter and orbital parameters. Most of the objects in our sample are dark (pv < 7%) and most of them are small (D < 120km). However, there is no correlation between albedo and diameter, in particular for the group of the small objects as albedo values are homogeneously distributed between 4 to 16%. The correlation with the color of the objects showed that red objects are all small (mean diameter 65 km), while the gray ones span a wide range of sizes (mean diameter 120 km). Moreover, the gray objects tend to be darker, with a mean albedo of 5.6%, compared with a mean of 8.5% (ranging from 5 to 15%) for the red objects., 16 pages, 7 figures. accepted at A&A. in press
Published: 2014
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26. The May 4, 2013 Stellar Occultation by Pluto and Implications for Pluto's Atmosphere

Author: Olkin, Catherine B., Young, Leslie A., Borncamp, D., Pickles, A., Sicardy, Bruno, Assafin, Marcelo, Bianco, F. B., Buie, M., Colas, François, Dias-Oliveira, Alex, Gillon, Michel, French, Richard G., Gomes, A. Ramos, Jehin, Emmanuel, Morales, Nicolas, Opitom, Cyrielle, Ortiz, José Luiz, Maury, Alain, Norbury, M., Ribas, F. B., Smith, R., Wasserman, L. H., Young, E. F., Zacharias, M., Zacharias, Norbert, SwRI, Las Cumbres Observatory, Goleta, Observatoire de Paris, Université Paris sciences et lettres (PSL), Observatório do Valongo, Universidade Federal do Rio de Janeiro, Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatorio Nacional / MCTI, Brazil, University of Liège, Wellesley College, Instituto de Astrofisica de Andalucia, CSIC (IAA), San Pedro de Atacama Celestial Explorations, Astrophysics Research Institute [Liverpool] (ARI), Liverpool John Moores University (LJMU), Lowell Observatory, Flagstaff, United States Naval Observatory (USNO), and Henry, Florence
Subjects: [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; On May 4 2013, Pluto passed in front of a 14 star and the shadow was well observed from multiple occultation groups. This paper presents results from the three light curves observed at Las Cumbres Observatory Global Telescope Network (LCOGT) from their Cerro Tololo site. The three LCOGT telescopes have 1.0 m apertures and used identical frame-transfer cameras. The cameras currently have a 2 second readout time therefore autonomous observations were scheduled with different exposure times to give good time resolution of the event. We will present results of this occultation and compare occultation results from 1988 to 2013 with volatile transport models.
Published: 2013

27. Possible routes to spin up fission for the formation of asteroid binaries and pairs

Author: Tanga, P., Campo Bagatin, A., Thirouin, A., Alberto Cellino, Comito, C., Ortiz, J. L., Hestroffer, D., Richardson, D. C., Joseph Louis LAGRANGE (LAGRANGE), 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), Departamento de Física, ISTS, Instituto de Astrofisica de Andalucia, CSIC (IAA), INAF/Osservatorio Astronomico di Torino, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Department of Astronomy, University of Maryland
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Non-gravitational effects (such as the "YORP" acceleration by thermal emission) may change their angular momentum of asteroids up to a few tens of km to the point to prevent any kind of rotational stability. Once instability is enforced mass loss may happen in more or less abrupt ways and potentially create satellites. We are studying this problem by means of numerical simulations, which extend previous results. We show that under certain conditions the production of secondary objects of different sizes by direct splitting can be a rather common event.
Published: 2013

28. Stellar Occultations by Large TNOs on 2012: The February 3rd by (208996) 2003 AZ84, and the February 17th by (50000) Quaoar

Author: Braga-Ribas, F., Sicardy, Bruno, Ortiz, José Luiz, Duffard, René, Camargo, J. I. B., Lecacheux, Jean, Colas, François, Vachier, Frédéric, Tanga, Paolo, Sposetti, Stefano, Brosch, N., Kaspi, Shai, Manulis, Ilan, Baug, Tapas, Chandrasekhar, T., Ganesh, Shashkiran, Jain, J., Mohan, Vijay, Sharma, Amar, Garcia-Lozano, Rubén, Klotz, Alain, Frappa, Eric, Jehin, Emmanuel, Assafin, Marcelo, Vieira Martins, Roberto, Behrend, Raoul, Roques, Françoise, Widemann, Thomas, Morales, Nicolas, Thirouin, Audrey, Mahasena, Putra, Benkhaldoun, Zouhair, Daassou, Ahmed, Rinner, Claudine, Ofek, E. O., Henry, Florence, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), Observatorio Nacional / MCTI, Brazil, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Gnosca Observatory, Tel Aviv University (TAU), Weizmann Institute of Science, Israel, Physical Research Laboratory, Astronomy & Astrophysics Division, Inter-University Centre for Astronomy and Astrophysics (IUCAA), UP State Observatory, Observatorio Nazaret, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Euraster, University of Liège, Observatório do Valongo, Universidade Federal do Rio de Janeiro, Observatoire de Genève, Department of Astronomy and Bosscha Observatory, Oukaimeden Observatory, LPHEA, Cadi Ayyad University, Morocco, and Moroccan Oukaimeden Sky Survey, Morocco
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; On February 2012, two stellar occultation's by large Trans-neptunian Objects (TNO's) were observed by our group. On the 3rd, an event by (208996) 2003 AZ84 was recorded from Mont Abu Observatory and IUCAA Girawali Observatory in India and from Weizmann Observatory in Israel. On the 17th, a stellar occultation by (50000) Quaoar was observed from south France and Switzerland. Both occultations are the second observed by our group for each object, and will be used to improve the results obtained on the previous events. The occultation by 2003 AZ84 is the first multi-chord event recorded for this object. From the single chord event on January 8th 2011, Braga-Ribas et al. 2011 obtained a lower limit of 573 /- 21 km. From the 2012 occultation the longest chord has a size of 662 /- 50 km. The other chords will permit to determine the size and shape of the TNO, and derive other physical parameters, such as the geometric albedo. The Quaoar occultation was observed from south of France (Observatoire de la Côte d'Azur, TAROT telescope and Valensole) and from Gnosca, Switzerland. Unfortunately, all three sites in France are almost at the same Quaoar's latitude, so in practice, we have two chords that can be used to fit Quaoar's limb. The resulting fit will be compared with the results obtained by Braga-Ribas et al. 2011. Braga-Ribas F., Sicardy B., et al. 2011, EPSC-DPS2011, 1060.Ribas F., Sicardy B., et al. 2011, EPSC-DPS2011, 1060.
Published: 2012

29. Size, density, albedo and atmosphere limit of dwarf planet Eris from a stellar occultation

Author: Sicardy, Bruno, Ortiz, José Luiz, Assafin, Marcelo, Jehin, Emmanuel, Maury, Alain, Lellouch, Emmanuel, Gil-Hutton, Ricardo, Braga-Ribas, F., Colas, François, Lecacheux, Jean, Roques, Françoise, Santos-Sanz, Pablo, Morales, Nicolas, Thirouin, Audrey, Camargo, J. I. B., Vieira Martins, Roberto, Gillon, Michel, Manfroid, Jean, Behrend, Raoul, Widemann, Thomas, Instituto de Astrofisica de Andalucia, CSIC (IAA), Observatório do Valongo, Universidade Federal do Rio de Janeiro, University of Liège, San Pedro de Atacama Celestial Explorations, Observatoire de Paris, Université Paris sciences et lettres (PSL), Complejo Astronomico El Leoncito and San Juan National University, Argentina, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Observatorio Nacional / MCT, Brazil, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We report the observation of a multi-chord stellar occultation by the dwarf planet (136199) Eris. The event was observed on November 6, 2010 UT, from two sites in Chile. Our observation is consistent with a spherical Eris with radius RE=1163±6 km, density ?=2.52±0.05 g cm-3, and visible geometric albedo pV=0.96 0.09 -0.04. Besides being remarkably similar in size to Pluto, Eris appears as one of the intrinsically brightest objects of the solar system, with a density suggesting a mainly rocky interior. Upper limits of about 1 nbar are derived for the surface pressure of possible nitrogen, argon or methane atmospheres of the dwarf planet.
Published: 2011

30. Integral-field spectroscopy of (90482) Orcus-Vanth

Author: Audrey Thirouin, Benoit Carry, Francesca E. DeMeo, David Farrelly, Thomas G. Müller, J. Berthier, Daniel Hestroffer, Pedro Lacerda, A. Doressoundiram, Bruno Sicardy, Christophe Dumas, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), European Southern Observatory (ESO), Chemistry and biochemistry department, Utah State University (USU), Max-Planck-Institut für Extraterrestrische Physik (MPE), European Space Astronomy Centre (ESAC), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Université Paris Cité (UPCité), Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Instituto de Astrofisica de Andalucia, CSIC (IAA), Queen's University, Sorbonne Université (SU), European Southern Observatory, Utah State University, Max-Planck-Institut für Extraterrestriche Physik (MPE), Agence Spatiale Européenne (ESA), European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Phase (waves), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, Techniques: high angular resolution, Methods: observational, Techniques:imaging spectroscopy, Observatory, 0103 physical sciences, Field spectroscopy, 010303 astronomy & astrophysics, Spectrograph, 0105 earth and related environmental sciences, Orbital elements, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Kuiper belt objects: individual: (90482) Orcus, Very Large Telescope, Astronomy and Astrophysics, 13. Climate action, Space and Planetary Science, Absorption band, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. We seek to constrain the surface composition of the Trans-Neptunian Object (90482) Orcus and its small satellite Vanth, as well as their mass and density. Methods. We acquired near-infrared spectra (1.4-2.4 {\mu}m) of (90482) Orcus and its companion Vanth using the adaptive-optics-fed integral-field spectrograph SINFONI mounted on Yepun/UT4 at the European Southern Observatory Very Large Telescope. We took advantage of a very favorable appulse (separation of only 4") between Orcus and the UCAC2 29643541 star (R = 11.6) to use the adaptive optics mode of SINFONI, allowing both components to be spatially resolved and Vanth colors to be extracted independently from Orcus. Results. The spectrum of Orcus we obtain has the highest signal-to-noise ratio to date, and we confirm the presence of H2O ice in crystalline form, together with the presence of an absorption band at 2.2 {\mu}m. We set an upper limit of about 2% for the presence of methane, and 5% for ethane. Because the methane alone cannot account for the 2.2 {\mu}m band, the presence of ammonia is suggested to the level of a couple of percent. The colors of Vanth are found slightly redder than those of Orcus, but the large measurement uncertainties forbid us from drawing conclusions on the origin of the pair (capture or co-formation). Finally, we reset the orbital phase of Vanth around Orcus, and confirm the orbital parameters derived by Brown et al. (2010, AJ 139)., Comment: 9 pages, 6 figures, 6 tables, accepted for publication in A&A
Published: 2011
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31. Monitoring a high-amplitude delta Scuti star for 152 days: discovery of 12 additional modes and modulation effects in the light curve of CoRoT 101155310

Author: Margit Paparo, Werner W. Weiss, Jonas Debosscher, L. Mantegazza, J. M. Benko, Zsofia Bognar, Michel Auvergne, A. Moya, Rafa Garrido, Frédéric Baudin, Ennio Poretti, Ewa Niemczura, Juan Carlos Suárez, Monica Rainer, Annie Baglin, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Institut für Astronomie, Universität Wien (IfA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Centro de Astrobiología LAEX (CSIC-INTA), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astronomical Institute, University of Wroclaw, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Etoile, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), and Instituut voor Sterrenkunde, Katholieke Universiteit Leuven
Subjects: oscillations [stars], Blazhko effect, rr-lyrae stars, FOS: Physical sciences, Astrophysics, oscillation code, rotation, Spectral line, variable-stars, Modulation (music), bolometric corrections, variables: delta scuti [stars], 2mass, Solar and Stellar Astrophysics (astro-ph.SR), Physics, interiors [stars], Oscillation, petersen diagrams, excitation, Astronomy and Astrophysics, Light curve, Stars, Amplitude, pulsating stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Noise (radio), individual: corot 101155310 [stars]
Abstract: The detection of small-amplitude nonradial modes in high-amplitude Delta Sct (HADS) variables has been very elusive until at least five of them were detected in the light curve of V974 Oph obtained from ground-based observations. The combination of radial and nonradial modes has a high asteroseismic potential, thanks to the strong constraints we can put in the modelling. The continuous monitoring of ASAS 192647-0030.0=CoRoT 101155310 (P=0.1258 d, V=13.4) ensured from space by the CoRoT (Convection, Rotation and planetary Transits) mission constitutes a unique opportunity to exploit such potential. The 22270 CoRoT measurements were performed in the chromatic mode. They span 152 d and cover 1208 consecutive cycles. After the correction for one jump and the long-term drift, the level of the noise turned out to be 29 micromag. The phase shifts and amplitude ratios of the coloured CoRoT data, the HARPS spectra, and the period-luminosity relation were used to determine a self-consistent physical model. In turn, it allowed us to model the oscillation spectrum, also giving feedback on the internal structure of the star. In addition to the fundamental radial mode f1=7.949 c/d with harmonics up to 10f1, we detected 12 independent terms. Linear combinations were also found and the light curve was solved by means of 61 frequencies (smallest amplitude 0.10 mmag). The newest result is the detection of a periodic modulation of the f1 mode (triplets at +/-0.193 c/d centred on f1 and 2f1), discussed as a rotational effect or as an extension of the Blazhko effect to HADS stars. The physical model suggests that CoRoT 101155310 is an evolved star, with a slight subsolar metallic abundance, close to the terminal age main sequence. All the 12 additional terms are identified with mixed modes in the predicted overstable region., 10 pages, 6 figures, Tables 1 and 2 available at CDS after publication. Accepted for publication in Astronomy and Astrophysics
Published: 2011
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32. Stellar Occultations by TNOs: the January 08, 2011 by (208996) 2003 AZ84 and the May 04, 2011 by (50000) Quaoar

Author: Braga-Ribas, F., Sicardy, Bruno, Ortiz, José Luiz, Jehin, Emmanuel, Camargo, J. I. B., Assafin, Marcelo, Behrend, Raoul, Unda-Sanzana, E., Colque, J. P., Morales, Nicolas, Tancredi, Gonzalo, Roland, S., Bruzzone, S., Salvo, R., Almenares, L., Emilio, Marcelo, Schoenell, William, Gil-Hutton, Ricardo, Milone, A. C., Jacques, C., Vanzi, Leonardo, Kavelaars, J. J., Cacella, P., Maury, Alain, Alvarez, E., van der Bliek, N. S., Vieira Martins, Roberto, Colas, François, Lecacheux, Jean, Vachier, Frédéric, Roques, Françoise, Widemann, Thomas, Thirouin, Audrey, Gillon, Michel, Manfroid, Jean, Bergengruen, A., Martínez, M., Capeche, J., Amorim, A., Pimentel, E., Leiva, Rodrigo, Toledo, I., Almeida, L. A., Magalhães, V. S., Montaña, C. E., Rodrigues, C. V., Henry, Florence, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Observatorio Nacional/MCT, Brazil, Instituto de Astrofisica de Andalucia, CSIC (IAA), University of Liège, Observatório do Valongo, Universidade Federal do Rio de Janeiro, Observatoire de Genève, Instituto de Astronomia, Universidad Catolica del Norte, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Between February 2010 and May 2011, our group has observed five stellar occultations by Trans-Neptunian Objects (TNOs), giving the size and shape for some of the biggest TNO's: Varuna, Eris, 2003 AZ84, Makemake and Quaoar. Here we present two of them: the January 08 stellar occultation by 2003 AZ84, and the May 04 by Quaoar. For the event of 2003 AZ84 we obtained one positive and another negative occultation chords in Chile. We give a lower limit to the diameter of the TNO. The event of Quaoar was observed from 16 sites distributed in Uruguay, Argentina, Chile and Brazil. Five of them yielded positive detection of the occultation. A preliminary analysis shows that the body is probably elongated and significantly bigger than the size determined by Fraser & Brown 2010, with a diameter of 890km. Using the size determined by the occultation, we will discuss the implications for the body density and albedo determination. The upper limit of the atmosphere is also studied.
Published: 2011

33. First detection of hydrogen isocyanide (HNC) in Titan's atmosphere

Author: Paul Hartogh, L. M. Lara, Miriam Rengel, R. Moreno, Dominique Bockelée-Morvan, Emmanuel Lellouch, Régis Courtin, A. Gonzalez, Marek Banaszkiewicz, N. Biver, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Instituto de Astrofisica de Andalucia, CSIC (IAA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, and Space Research Centre, Polish Academy of Sciences (Wroclaw)
Subjects: Physics, Hydrogen isocyanide, Rotational transition, Astronomy and Astrophysics, symbols.namesake, chemistry.chemical_compound, chemistry, Space and Planetary Science, symbols, Radiative transfer, Emission spectrum, Atomic physics, Thermosphere, Ionosphere, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Dissociative recombination
Abstract: International audience; We report on the first identification of hydrogen isocyanide (HNC) in Titan's atmosphere, from observations using the HIFI instrument on the Herschel Space Observatory. An emission line from the HNC J = 6 --> 5 rotational transition at 543.897 GHz was measured in Titan on June 14 and December 31, 2010. Radiative transfer modeling indicates that the bulk of HNC is located above 400 km, with a column density in the range (0.6-1.5) × 1013 cm-2, but the observations cannot establish its vertical profile. In particular HNC could be restricted to the upper thermosphere (~1000 km), in which case its local abundance relative to HCN could be as high as ~0.3. HNC is probably formed mostly at ionospheric levels (950-1150 km) from dissociative recombination of HCNH+ and possibly other heavier nitrile ions. Ionospheric loss of HNC occurs by protonation with XH+ ions. Additional formation (e.g. from N(4S) +3CH2) and loss routes (e.g. from isomerization to HCN) in the neutral atmosphere remain to be investigated.
Published: 2011
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34. Kepler observations of the variability in B-type stars

Author: Balona, Luis, Pigulski, Andrzej, Cat, P. De, Handler, Gerald, Gutiérrez, Juan, Engelbrecht, C. A., Frescura, F., Briquet, Maryline, Cuypers, J., Daszynska-Daszkiewicz, J., Degroote, Pieter, Dukes, R. J., Garcia, Rafael A., Green, E. M., Heber, U., Kawaler, Steven D., Lehmann, H., Leroy, A., Molenda-Zakowicz, Joanna, Neiner, Coralie, Noels, Arlette, Nuspl, J., Østensen, R., Pricopi, D., Roxburgh, Ian W., Salmon, Sébastien, Smith, Myron A., Suárez, Juan Carlos, Suran, M. D., Szabó, Robert, Uytterhoeven, K., Christensen-Dalsgaard, Jörgen, Kjeldsen, Hans, Caldwell, Douglas A., Girouard, F. R., Sanderfer, Dwight T., South African Astronomical Observatory (SAAO), Instytut Astronomiczny, Uniwersytet Wroclawski, Koninklijke Sterrenwacht van België, Institut für Astronomie, Universität Wien (IfA), Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Etoile, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Department of Physics, University of Johannesburg, School of Physics, University of the Witwatersrand, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Department of Physics and Astronomy, College of Charleston, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Steward Observatory, University of Arizona, Dr. Karl Remeis-Sternwarte, Astronomisches Institut, Universität Erlangen-Nuremberg, Department of Physics and Astronomy, Iowa State University, Thüringer Landessternwarte, Tautenburg Observatory, Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège, Queen Mary University of London, Mile End Road, Astronomical Institute of the Romanian Academy, Bucharest, Space Telescope Science Institute (STScI), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Department of Physics and Astronomy, Aarhus University, SETI Institute, NASA Ames Research Center, Moffett Field, and Orbital Sciences Corporation, NASA Ames Research Center, Moffett Field
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies characteristic of SPB stars. Seven of these stars also show a few weak, isolated high frequencies and they could be considered as SPB/beta Cep hybrids. In all cases the frequency spectra are quite different from what is seen from ground-based observations. We suggest that this is because most of the low frequencies are modes of high degree which are predicted to be unstable in models of mid-B stars. We find that there are non-pulsating stars within the beta Cep and SPB instability strips. Apart from the pulsating stars, we can identify stars with frequency groupings similar to what is seen in Be stars but which are not Be stars. The origin of the groupings is not clear, but may be related to rotation. We find periodic variations in other stars which we attribute to proximity effects in binary systems or possibly rotational modulation. We find no evidence for pulsating stars between the cool edge of the SPB and the hot edge of the delta Sct instability strips. None of the stars show the broad features which can be attributed to stochastically-excited modes as recently proposed. Among our sample of B stars are two chemically peculiar stars, one of which is a HgMn star showing rotational modulation in the light curve., Comment: 19 pages, 11 figures, 4 tables
Published: 2011
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35. Non-LTE CO limb emission at 4.7mum in the upper atmosphere of Venus, Mars and Earth: Observations and modeling

Author: Gilli, G., Lopez-Valverde, Miguel, Funke, B., López-Puertas, Manuel, Drossart, Pierre, Piccioni, Giuseppe, Formisano, Vittorio, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), Istituto di Fisica dello Spazio Interplanetario (IFSI), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We report here on CO limb observations in Mars, Venus and Earth and their model simulations. A comparative study of the CO emission, including the most recent spacecraft observations of the three planets' atmospheres, has been performed. Strong daytime emissions near 4.7mum have been recently observed in the limb of the upper atmosphere of the three terrestrial planets by the Planetary Fourier Spectrometer on Mars Express ( Formisano et al., 2005), the Visible and Infrared Thermal Imaging Spectrometer on Venus Express ( Drossart et al., 2007), and the Michelson Interferometer for Passive Atmosphere Sounding on Envisat ( Fischer et al., 2008). Those emissions are produced by solar pumping of molecular vibrations and non-local thermodynamic equilibrium (non-LTE) models are used to explain them in a consistent framework for the three atmospheres. The maximum of the 4.7mum emission occurs on Venus between 90 and 110 km, on Mars above 60 km, and on Earth around 68 km. The observations show that the fundamental band dominates the CO non-LTE emission on Earth, while on Venus and Mars the larger contribution comes from the first hot band transition. The main goal of this study is to understand those differences and similarities with the help of theoretical simulations with optical thickness considerations, and compare the capability of space instrumentation for the remote sounding of the atmospheres in this spectral region.
Published: 2011
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36. Atmospheric parameters and pulsational properties for a sample of delta Sct, gamma Dor and hybrid Kepler targets

Author: Catanzaro, G., Ripepi, V., Bernabei, S., Marconi, M., Balona, L., Kurtz, D. W., Smalley, B., Borucki, W. J., Bruntt, H., Christensen-Dalsgaard, J., Grigahcene, A., Kjeldsen, H., Koch, D. G., Monteiro, M. J. P. F. G., Suarez, J. C., Szabo, R., Uytterhoeven, K., INAF-Osservatorio Astrofisico di Catania (INAF-OACt), INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), INAF-Osservatorio Astronomico di Bologna (OABO), South African Astronomical Observatory (SAAO), Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, Astrophysics Group, Keele University, National Aeronautics and Space Administration, Ames Research Center, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Etoile, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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), Department of Physics and Astronomy, Aarhus University, Centro de Astrofísica, Universidade do Porto, Instituto de Astrofisica de Andalucia, CSIC (IAA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: We report spectroscopic observations for 19 $\delta$\,Sct candidates observed by the {\it Kepler} satellite both in long and short cadence mode. For all these stars, by using spectral synthesis, we derive the effective temperature, the surface gravity and the projected rotational velocity. An equivalent spectral type classification has been also performed for all stars in the sample. These determinations are fundamental for modelling the frequency spectra that will be extracted from the {\it Kepler} data for asteroseismic inference. For all the 19 stars, we present also periodograms obtained from {\it Kepler} data. We find that all stars show peaks in both low- ($\gamma$\,Dor; g mode) and high-frequency ($\delta$\,Sct; p mode) regions. Using the amplitudes and considering 5\,c/d as a boundary frequency, we classified 3 stars as pure $\gamma$\,Dor, 4 as $\gamma$\,Dor\,-\,$\delta$\ hybrid, Sct, 5 as $\delta$\,Sct\,-\,$\gamma$\,Dor hybrid, and 6 as pure $\delta$\,Sct. The only exception is the star KIC\,05296877 which we suggest could be a binary., Comment: 11 pages, 6 figures, MNRAS main journal
Published: 2011
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37. A Photometric And Astrometric Study Of The Trans-neptunian Object Orcus

Author: Ortiz, José Luiz, Cikota, A., Cikota, S., Hestroffer, Daniel, Thirouin, Audrey, Morales, Nicolas, Duffard, René, Gil-Hutton, Ricardo, Santos-Sanz, Pablo, de la Cueva, I., Instituto de Astrofisica de Andalucia, CSIC (IAA), Physik-Institut, Universität Zürich, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 de Lille-Centre National de la Recherche Scientifique (CNRS), Complejo Astronómico El Leoncito (CASLEO), and Astroimagen
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We obtained high precision relative astrometry and photometry of Orcus' system with respect to background stars. The Right Ascension residuals of an orbital fit to the astrometric data revealed a period of 9.7 ± 0.3 days, which is what one would expect to be induced by the known Orcus companion (Vanth). The residuals also are correlated with the theoretical positions of the satellite relative to the primary. The oscillation in the residuals is due to the photocenter motion of the combined Orcus plus satellite system around the barycenter along an orbital revolution of the satellite. We show here that detecting some binaries through a carefully devised astrometric technique might be feasible with telescopes of moderate size. We have also analyzed the system's mid-term photometry in order to determine whether the rotation could be tidally locked to the satellite's orbital period. We found that a photometric variability of 9.7 ± 0.3 days is clear in our data, nearly coincident with the orbital period of the satellite. We believe this variability might be induced by the satellite's rotation. In our photometry there is also a slight hint for an additional very small variability in the 10 hr range that was already reported in the literature. Such short-term variability would indicate that the primary is not tidally locked and therefore the system would not have reached a double synchronous state. From angular momentum considerations we suspect that Orcus satellite might have formed from a rotational fission. This requires that the mass of the satellite would be around 0.09 times that of the primary, close to the value that one derives by using an albedo of 0.12 for the satellite and assuming equal densities for both the primary and secondary.
Published: 2010

38. Astrometry and photometry of Orcus from a 33-day campaign

Author: Ortiz, José Luiz, Cikota, A., Hestroffer, Daniel, Cikota, S., Thirouin, Audrey, Molina, Antonio, Morales, Nicolas, Duffard, René, Gil-Hutton, Ricardo, Santos-Sanz, Pablo, Instituto de Astrofisica de Andalucia, CSIC (IAA), Physik-Institut, Universität Zürich, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 de Lille-Centre National de la Recherche Scientifique (CNRS), Universidad de Granada = University of Granada (UGR), and Complejo Astronómico El Leoncito (CASLEO)
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Not Available
Published: 2010

39. On the interpretation of echelle diagrams for solar-like oscillations. Effect of centrifugal distortion

Author: François Lignières, Daniel R. Reese, Michel Rieutord, Marie-Jo Goupil, Juan Carlos Suárez, Reza Samadi, J. Lochard, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Oscillation, Stellar rotation, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Rotation, Spectral line, Computational physics, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Solar-like oscillations, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: This work aims at determining the impact of slow to moderate rotation on the regular patterns often present in solar-like oscillation spectra. We focus on the well-known asteroseismic diagnostic echelle diagrams, examining how rotation may modify the estimates of the large and small spacings, as well as the identification of modes. We illustrate the work with a real case: the solar-like star $\eta$ Bootis. The modeling takes into account rotation effects on the equilibrium models through an effective gravity and on the oscillation frequencies through both perturbative and non-perturbative calculations. We compare the results of both type of calculations in the context of the regular spacings (like the small spacings and the scaled small spacings) and echelle diagrams. We show that for echelle diagrams the perturbative approach remains valid for rotational velocities up to 40-50 km/s. We show that for the rotational velocities measured in solar-like stars, theoretical oscillation frequencies must be corrected up to the second-order in terms of rotation rate, including near degeneracy effects. For rotational velocities of about 16 km/S and higher, diagnostics on large spacings and on modal identification through echelle diagrams can be significantly altered by the presence of the $m\neq0$ components of the rotationally split modes. We found these effects to be detectable in the observed frequency range. Analysis of the effects of rotation on small spacings and scaled small spacings reveals that these can be of the order of, or even larger than surface effects, typically turbulence, microscopic diffusion, etc. Furthermore, we show that scaled spacings are significantly affected by stellar distortion even for small stellar rotational velocities (from 10-15 km/s) and therefore some care must be taken when using them as indicators for probing deep stellar interiors., Comment: 10 pages,5 figures, accepted for publication in ApJ; http://iopscience.iop.org/0004-637X/721/1/537/
Published: 2010
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40. Water production in comet 81P/Wild 2 as determined by Herschel/HIFI

Author: Nicolas Biver, Emmanuel Jehin, A. Di Giorgio, Miriam Rengel, M. I. Błęcka, José Cernicharo, Geoffrey A. Blake, S. Philipp, M. de Val-Borro, Christoffel Waelkens, Joris Blommaert, Slawomira Szutowicz, R. Szczerba, Alexander S. Medvedev, Michael Küppers, Pierre Encrenaz, Dariusz C. Lis, Paul Hartogh, Paolo Saraceno, T. Encrenaz, David A. Naylor, Bart Vandenbussche, Dominique Bockelée-Morvan, Raphael Moreno, Luisa Lara, Volker Ossenkopf, P. Zaal, Emmanuel Lellouch, R. Shipman, Martin Emprechtinger, Leen Decin, B. M. Swinyard, T. de Graauw, F. Bensch, Jacques Crovisier, C. Jarchow, R. Schieder, Jean Manfroid, N. Thomas, Marek Banaszkiewicz, T. Klein, M. Kidger, Edwin Bergin, Daphne Stam, Damien Hutsemekers, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Space Research Centre, Polish Academy of Sciences (Wroclaw), German Aerospace Centre (DLR), Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège, Rosetta Science Operations Centre, Instituto de Astrofisica de Andalucia, CSIC (IAA), STFC Rutherford Appleton Laboratory, Harwell Innovation Campus, Didcot, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Astronomy Department, University of Michigan, Laboratorio de Astrofísica Molecular, CAB-CSIC/INTA (LAM), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Dynamique des milieux interstellaires et plasmas stellaires, Joint ALMA Observatory, Santiago, Science Centre, Department of Physics and Astronomy, University of Lethbridge, Physikalisches Institut, Universität zu Köln, SRON Netherlands Institute for Space Research, Physikalisches Institut, Universität Bern, Centrum Astronomiczne im. M. Kopernika, Torun (CAMK), Istituto Fisica Spazio Interplanetario, INAF, Max-Planck-Institut für Radioastronomie (MPIfR), and Astronomy
Subjects: Electron density, 010504 meteorology & atmospheric sciences, Mean kinetic temperature, SURFACE, Infrared, Comet, FOS: Physical sciences, Astrophysics, Electron, 01 natural sciences, SPACECRAFT, 0103 physical sciences, H2O, Spectral resolution, 010303 astronomy & astrophysics, SATELLITE, 0105 earth and related environmental sciences, Line (formation), Physics, Earth and Planetary Astrophysics (astro-ph.EP), ASTRONOMY, Astronomy and Astrophysics, submillimeter: general, molecular processes, 13. Climate action, Space and Planetary Science, radiative transfer, ODIN, comets: individual: 81P/Wild 2, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation, HIFI, Astrophysics - Earth and Planetary Astrophysics
Abstract: The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this letter we present HIFI observations of the fundamental 110-101 (557 GHz) ortho and 111-000 (1113 GHz) para rotational transitions of water in comet 81P/Wild 2 acquired in February 2010. We mapped the extent of the water line emission with five point scans. Line profiles are computed using excitation models which include excitation by collisions with electrons and neutrals and solar infrared radiation. We derive a mean water production rate of $1.0 \times 10^{28}$ molecules s$^{-1}$ at a heliocentric distance of 1.61 AU about 20 days before perihelion, in agreement with production rates measured from the ground using observations of the 18-cm OH lines. Furthermore, we constrain the electron density profile and gas kinetic temperature, and estimate the coma expansion velocity by fitting the water line shapes., Accepted for publication in A&A (special issue on HIFI first results)
Published: 2010
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41. A study of the distant activity of comet C/2006 W3 (Christensen) using Herschel and ground-based radio telescopes

Author: L. M. Lara, Trevor Fulton, Miriam Rengel, M. R. Kidger, G. A. Blake, R. Moreno, Emmanuel Jehin, E. Lellouch, Michael Küppers, David A. Naylor, C. Waelkens, D. C. Lis, T. de Graauw, E. A. Bergin, Jean Manfroid, M. I. Blecka, T. Encrenaz, M. de Val-Borro, L. Decin, J. Crovisier, Slawomira Szutowicz, Christopher Jarchow, Bart Vandenbussche, José Cernicharo, J. A. D. L. Blommaert, Damien Hutsemekers, N. Thomas, Paul Hartogh, Dominique Bockelée-Morvan, Alexander S. Medvedev, Sarah Leeks, Marek Banaszkiewicz, Rudolf Schieder, P. J. Encrenaz, F. Bensch, B. M. Swinyard, N. Biver, Martin Emprechtinger, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Rutherford Appleton Laboratory, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège, European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Instituto de Astrofisica de Andalucia, CSIC (IAA), Space Research Centre, Polish Academy of Sciences (Wroclaw), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Blue Sky Spectroscopy (BSS), Herschel Science Center, ESAC/ESA, Astronomy Department, University of Michigan, Centro de Astrobiología, Consejo Superior de Investigaciones Científicas (CSIC)/Instituto Nacional de Técnica Aeroespacial (INTA) (CAB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Dynamique des milieux interstellaires et plasmas stellaires, SRON Netherlands Institute for Space Research, Department of Physics, University of Lethbridge, Lulea University of Technology (LTU), and University of Bern (UBERN)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Range (particle radiation), Continuum (design consultancy), Comet, FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, Spectral line, Radio telescope, Spire, Space and Planetary Science, Spectral energy distribution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Comet C/2006 W3 (Christensen) was observed in November 2009 at 3.3 AU from the Sun with Herschel. The PACS instrument acquired images of the dust coma in 70- and 160-micrometers filters, and spectra covering several H2O rotational lines. Spectra in the range 450-1550 GHz were acquired with SPIRE. The comet emission continuum from 70 to 672 micrometers was measured, but no lines were detected. The spectral energy distribution indicates thermal emission from large particles and provides a measure of the size distribution index and dust production rate. The upper limit to the water production rate is compared to the production rates of other species (CO, CH3OH, HCN, H2S, OH) measured with the IRAM 30-m and Nancay telescopes. The coma is found to be strongly enriched in species more volatile than water, in comparison to comets observed closer to the Sun. The CO to H2O production rate ratio exceeds 220%. The dust to gas production rate ratio is on the order of 1., Accepted for publication in Astronomy & Astrophysics (special issue on Herschel first results)
Published: 2010
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42. Photometric variability of the Be star CoRoT-ID 102761769

Author: Anne-Marie Hubert, Coralie Neiner, B. de Batz, Annie Baglin, T. Semaan, Juan Gutiérrez-Soto, M. Floquet, Yves Fremat, Marcelo Emilio, P. D. Diago, J. Suso, Christophe Martayan, B. Leroy, A. L. Huat, Eduardo Janot-Pacheco, L. Andrade, Juan Fabregat, F. Espinosa Lara, Juan Carlos Suárez, Obervatório Astronômico, Universidade Estadual de Ponta Grossa, Instituto Astronômico e Geofísico, Universidade de São Paulo (IAG), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Universitat de València (UV), Instituto de Astrofisica de Andalucia, CSIC (IAA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatoire Royal de Belgique (ORB), and European Organization for Astronomical Research in the Southern Hemisphere
Subjects: 010504 meteorology & atmospheric sciences, Be star, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Type (model theory), 01 natural sciences, Partícules (Física nuclear), Luminosity, symbols.namesake, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Stellar rotation, Balmer series, Astronomy and Astrophysics, Circumstellar envelope, Light curve, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Esteroides, symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Classical Be stars are rapid rotators of spectral type late O to early A and luminosity class V-III, wich exhibit Balmer emission lines and often a near infrared excess originating in an equatorially concentrated circumstellar envelope, both produced by sporadic mass ejection episodes. The causes of the abnormal mass loss (the so-called Be phenomenon) are as yet unknown. For the first time, we can now study in detail Be stars outside the Earth's atmosphere with sufficient temporal resolution. We investigate the variability of the Be Star CoRoT-ID 102761769 observed with the CoRoT satellite in the exoplanet field during the initial run. One low-resolution spectrum of the star was obtained with the INT telescope at the Observatorio del Roque de los Muchachos. A time series analysis was performed using both cleanest and singular spectrum analysis algorithms to the CoRoT light curve. To identify the pulsation modes of the observed frequencies, we computed a set of models representative of CoRoT-ID 102761769 by varying its main physical parameters inside the uncertainties discussed. We found two close frequencies related to the star. They are 2.465 $\rm c\,d^{-1}$ (28.5 $\mathrm{\mu Hz}$) and 2.441 $\rm c\,d^{-1}$ (28.2 $\mathrm{\mu Hz}$). The precision to which those frequencies were found is 0.018 $\rm c\,d^{-1}$ (0.2 $\mathrm{\mu Hz}$). The projected stellar rotation was estimated to be 120 $\rm km\,s^{-1}$ from the Fourier transform of spectral lines. If CoRoT-ID 102761769 is a typical Galactic Be star it rotates near the critical velocity. The critical rotation frequency of a typical B5-6 star is about 3.5 $\rm c\,d^{-1}$(40.5 $\mathrm{\mu Hz}$), which implies that the above frequencies are really caused by stellar pulsations rather than star's rotation., Comment: 9 pages, 8 figures, accepted: 13 June 2010 Astronomy & Astrophysics
Published: 2010
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43. Modelling results for two late Be stars observed by CoRoT

Author: Juan Gutiérrez-Soto, Hideyuki Saio, C. Lovekin, Coralie Neiner, S. Mathis, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomical Institute, Tohoku University, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Photosphere, K-type main-sequence star, Astronomy, Astronomy and Astrophysics, Astrophysics, Rotation, Stars, Amplitude, Space and Planetary Science, Stellar mass loss, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Adiabatic process, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution
Abstract: The Be stars HD 181231 (B5IVe) and HD 175869 (B8IIIe) have recently been observed using the CoRoT satellite for ∼5 months and ∼27 days respectively. This continuous, space-based observation has allowed for the detection of many low amplitude modes in these stars. In the case of HD181231, the combination of the CoRoT data and ground-based spectroscopic follow-up data have placed tight constraints on the fundamental and pulsational properties of the star, allowing for detailed seismic modelling. For HD 175869, the variability has been proposed to be the result of inhomogeneities produced by stellar activity, located in or just above the photosphere. However, the CoRoT data does not exclude non-radial pulsations as the origin of the variability. Through seismic modelling, we hope to clarify the origins of the variability. We compare observed frequencies to those calculated using a 2D stellar evolution and a 2D linear adiabatic pulsation code. We match the observed frequencies to a grid of 2D models in order to constrain the mass, age, rotation velocity and amount of convective core overshoot. We also compare our results to frequencies calculated using a 1D non-adiabatic pulsation code. Using a combination of frequencies, we have been able to constrain the rotation and extra mixing for stars of a known mass and age. Here we determine the best fitting mass, age, rotation velocity and amount of extra mixing for these Be stars (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Published: 2010
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44. Ground-based follow-up in relation to Kepler Asteroseismic Investigation

Author: K. Uytterhoeven, M. Briquet, H. Bruntt, P. De Cat, S. Frandsen, J. Gutiérrez-Soto, L. Kiss, D.W. Kurtz, M. Marconi, J. Molenda-Żakowicz, R. Østensen, S. Randall, J. Southworth, R. Szabó, null KASC Working Groups on ground-based, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Observatoire Royal de Belgique (ORB), Danish AsteroSeismology Centre (DASC), Instituto de Astrofisica de Andalucia, CSIC (IAA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Instytut Astronomiczny, Uniwersytet Wroclawski, European Southern Observatory (ESO), and University of Warwick [Coventry]
Subjects: Physics, Metallicity, Newtonian telescope, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Nordic Optical Telescope, law.invention, Telescope, Stars, Photometry (astronomy), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Observatory, law, William Herschel Telescope, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The Kepler space mission, successfully launched in March 2009, is providing continuous, high-precision photometry of thousands of stars simultaneously. The uninterrupted time-series of stars of all known pulsation types are a precious source for asteroseismic studies. The Kepler data do not provide information on the physical parameters, such as effective temperature, surface gravity, metallicity, and vsini, which are crucial for successful asteroseismic modelling. Additional ground-based time-series data are needed to characterize mode parameters in several types of pulsating stars. Therefore, ground-based multi-colour photometry and mid/high-resolution spectroscopy are needed to complement the space data. We present ground-based activities within KASC on selected asteroseismic Kepler targets of several pulsation types. (Based on observations made with the Isaac Newton Telescope, William Herschel Telescope, Nordic Optical Telescope, Telescopio Nazionale Galileo, Mercator Telescope (La Palma, Spain), and IAC-80 (Tenerife, Spain). Also based on observations taken at the observatories of Sierra Nevada, San Pedro Martir, Vienna, Xinglong, Apache Point, Lulin, Tautenburg, Loiano, Serra la Nave, Asiago, McDonald, Skinakas, Pic du Midi, Mauna Kea, Steward Observatory, Mt Wilson, Bialkow Observatory of the Wroclaw University, Piszkesteto Mountain Station, Observatoire de Haute Provence, and Centro Astronomico Hispano Aleman at Calar Alto. Based on data from the AAVSO International Database.), Comment: 4 pages, 1 figure, Astronomische Nachrichten, HELASIV conference, Lanzarote, February 2010, submitted
Published: 2010
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45. 'TNOs are Cool': A survey of the trans-Neptunian region. I. Results from the Herschel science demonstration phase (SDP)

Author: B. M. Swinyard, Miriam Rengel, L. M. Lara, T. G. Mueller, Paul Hartogh, S. Fornasier, R. Moreno, Nicolas Thomas, Esa Vilenius, Olivier Hainaut, Daniel Hestroffer, Jonathan Horner, Pablo Santos-Sanz, E. Dotto, John Stansberry, David Trilling, A. Delsanti, M. R. Kidger, P. J. Gutierrez, Tanya Lim, Rene Duffard, Alain Doressoundiram, J. Crovisier, Michael Mueller, Florence Henry, Michael Mommert, Pedro Lacerda, Cs. Kiss, Olivier Groussin, Audrey Thirouin, Alan W. Harris, Silvia Protopapa, Antonella Barucci, J. L. Ortiz, E. Lellouch, Max-Planck-Institut für Extraterrestriche Physik (MPE), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), University of Arizona (UoA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (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), Instituto de Astrofisica de Andalucia, CSIC (IAA), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics and Astronomy, Durham University, Queen's University [Belfast] (QUB), Space Science and Technology Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon UK, Department of Physics and Astronomy, Northern Arizona University, Flagstaff, INAF-Osservatorio Astronomico di Roma (INAF-OAR), European Southern Observatory (ESO), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Herschel Science Center, ESAC/ESA, University of Bern (UBERN), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Probabilités et Modèles Aléatoires (LPMA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Sonnensystemforschung (MPS), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Color temperature, 01 natural sciences, 0103 physical sciences, Thermal, Range (statistics), Kuiper belt: general / methods: observational / techniques: photometric / instrumentation: photometers / infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Debris disk, Mode (statistics), Astronomy and Astrophysics, Centaur, Albedo, Astrophysics - Astrophysics of Galaxies, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The goal of the Herschel Open Time Key programme "TNOs are Cool!" is to derive the physical and thermal properties for a large sample of Centaurs and trans-Neptunian objects (TNOs), including resonant, classical, detached and scattered disk objects. We present results for seven targets either observed in PACS point-source, or in mini scan-map mode. Spitzer-MIPS observations were included for three objects. The sizes of these targets range from 100 km to almost 1000 km, five have low geometric albedos below 10%, (145480) 2005 TB190 has a higher albedo above 15%. Classical thermal models driven by an intermediate beaming factor of $\eta$=1.2 or $\eta$-values adjusted to the observed colour temperature fit the multi-band observations well in most cases. More sophisticated thermophysical models give very similar diameter and albedo values for thermal inertias in the range 0-25 Jm-2s-0.5K-1, consistent with very low heat conductivities at temperatures far away from the Sun. The early experience with observing and model strategies will allow us to derive physical and thermal properties for our complete Herschel TNO sample of 140 targets as a benchmark for understanding the solar system debris disk, and extra-solar ones as well., Comment: 5 pages, 2 figures, accepted for publication in the A&A Herschel Special Issue
Published: 2010
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46. Observation of light echoes around very young stars

Author: Jose Luis Ortiz, Nicolás Morales, Mario Daniel Melita, Ricardo Gil-Hutton, Pablo Santos-Sanz, Rene Duffard, Ben Sugerman, I. de la Cueva, Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Physics and Astronomy, Goucher College, Astroimagen, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Complejo Astronómico El Leoncito (CASLEO), and Instituto de Astronomía y Física del Espacio, Universidade de Buenos Aires (IAFE)
Subjects: Physics, Solar System, Brightness, Be star, Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, T Tauri star, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Variable star, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The goal of the paper is to present new results on light echoes from young stellar objects. Broad band CCD images were obtained over three months at one-to-two week intervals for the field of NGC 6726, using the large field-of-view remotely-operated telescope on top of Cerro Burek. We detected scattered light echoes around two young, low-amplitude, irregular variable stars. Observations revealed not just one, but multiple light echoes from brightness pulses of the T Tauri star S CrA and the Herbig Ae/Be star R CrA. Analysis of S CrA's recurring echoes suggests that the star is located 138 +/- 16 pc from Earth, making these the closest echoes ever detected. The environment that scatters the stellar light from S CrA is compatible with an incomplete dust shell or an inclined torus some 10,000 AU in radius and containing $\sim$ $2 \times 10^{-3}$ $M_{\sun}$ of dust. The cause of such concentration at $\sim$ 10,000AU from the star is unknown. It could be the remnant of the envelope from which the star formed, but the distance of the cloud is remarkably similar to the nominal distance of the Oort cloud to the Sun, leading us to also speculate that the dust (or ice) seen around S CrA might have the same origin as the Solar System Oort cloud., Comment: A&A, in press Received: 16 March 2010 / Accepted: 01 June 2010
Published: 2010
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47. CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Monocerotis

Author: P. Mathias, M. Rainer, C. Neiner, M. Desmet, Carla Maceroni, Maryline Briquet, F. Baudin, Conny Aerts, E. Poretti, Patricia Lampens, Yves Fremat, Petr Harmanec, J. C. Valtier, E. Janot Pacheco, P. Degroote, K. Uytterhoeven, Andrej Prsa, Pedro J. Amado, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Observatoire Royal de Belgique (ORB), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Astronomical Institute, Charles University, Departamento de Astronomia Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire Hippolyte Fizeau (FIZEAU), 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), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Astronomy and Astrophysics, Villanova University, and INAF-Osservatorio Astronomico di Roma (INAF-OAR)
Subjects: Physics, Brightness, 010308 nuclear & particles physics, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Mass ratio, Light curve, 01 natural sciences, Photometry (optics), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Orbital motion, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Roche lobe, Circumbinary planet, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution \'echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Mon. We derived new, accurate ephemerides for both the orbital motion (with a period of 11.113d) and the long-term, overall brightness variation (with a period of 416.9d) of this strongly interacting Be + G semi-detached binary. It is shown that this long-term variation must be due to attenuation of the total light by some variable circumbinary material. We derived the binary mass ratio $M_{\rm G}/M_{\rm B}$ = 0.17\p0.03 based on the assumption that the G-type secondary fills its Roche lobe and rotates synchronously. Using this value of the mass ratio as well as the radial velocities of the G-star, we obtained a consistent light curve model and improved estimates of the stellar masses, radii, luminosities and effective temperatures. We demonstrate that the observed lines of the B-type primary may not be of photospheric origin. We also discover rapid and periodic light changes visible in the high-quality residual CoRoT light curves. AU Mon is put into perspective by a comparison with known binaries exhibiting long-term cyclic light changes., Comment: Accepted for publication in MNRAS
Published: 2010
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48. A PRECISE ASTEROSEISMIC AGE AND RADIUS FOR THE EVOLVED SUN-LIKE STAR KIC 11026764

Author: V. Silva Aguirre, Graham A. Verner, David G. Koch, J. Molenda-Zakowicz, O. L. Creevey, P. Eggenberger, William J. Chaplin, Daniel Huber, Savita Mathur, S. Frandsen, A.-M. Broomhall, T. S. Metcalfe, Tiago L. Campante, Stephen T. Fletcher, Michael Thompson, Antonio Frasca, Roger New, Alfio Bonanno, P.-O. Quirion, Rasmus Handberg, M. Di Mauro, I. N. Kitiashvili, D. Salabert, Jesper Schou, Timothy M. Brown, Timothy R. White, K. H. Sato, Timothy R. Bedding, S. Dreizler, Rafael A. García, Jørgen Christensen-Dalsgaard, Saskia Hekker, Juan Carlos Suárez, L. Esch, A. Moya, Hans Kjeldsen, Paul Wilson, J. P. Marques, Thierry Appourchaux, Clara Régulo, Yvonne Elsworth, Dennis Stello, G. Doğan, J. Ballot, Sarbani Basu, William J. Borucki, Jon M. Jenkins, R. L. Gilliland, Christoffer Karoff, Katia Biazzo, Alexander G. Kosovichev, S. G. Sousa, Ian W. Roxburgh, Ning Gai, M. Bazot, L. Piau, Mário J. P. F. G. Monteiro, H. Bruntt, Faculdade de Ciências, High Altitude Observatory, National Center for Atmospheric Research, Centro de Astrofísica, Universidade do Porto, University of Sheffield [Sheffield], Astronomical Institute, University of Wroclaw, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), School of Physics and Astronomy, University of Birmingham, Danish AsteroSeismology Centre (DASC), Observatoire Astronomique de l'Université de Genève, Sydney Institute for Astronomy (SIfA), Observatoire de Paris, Université Paris sciences et lettres (PSL), Instituto de Astrofísica de Canarias (IAC), Canadian Space Agency (CSA), INAF-Osservatorio Astrofisico di Catania (INAF-OACt), Max-Planck-Institut für Astrophysik (MPA), Department of Astronomy, Yale University, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), HEPL, Stanford University, Stanford, Center for Turbulence Research, Stanford University, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratorio de Astrofísica, CAB (CSIC-INTA), Villanueva de la Cañada, Madrid, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA), Institut für Astrophysik, Universität Göttingen, Nordic Optical Telescope, Las Cumbres Observatory, Goleta, Space Telescope Science Institute (STScI), Materials Engineering Research Institute, Sheffield Hallam University, Sheffield, Astronomy Unit, Queen Mary, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Aeronautics and Space Administration, Ames Research Center, and SETI Institute, NASA Ames Research Center, Moffett Field
Subjects: Astronomia, Física, Física [Ciências exactas e naturais], FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, Physical sciences [Natural sciences], Planet, Astronomy, Physical sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, Oscillation, Subgiant, Astronomy and Astrophysics, Radius, Exoplanet, Stars, Photometry (astronomy), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-like planets. The asteroseismic capabilities of the mission are being used to determine precise radii and ages for the target stars from their solar-like oscillations. Chaplin et al. (2010) published observations of three bright G-type stars, which were monitored during the first 33.5 days of science operations. One of these stars, the subgiant KIC 11026764, exhibits a characteristic pattern of oscillation frequencies suggesting that it has evolved significantly. We have derived asteroseismic estimates of the properties of KIC 11026764 from Kepler photometry combined with ground-based spectroscopic data. We present the results of detailed modeling for this star, employing a variety of independent codes and analyses that attempt to match the asteroseismic and spectroscopic constraints simultaneously. We determine both the radius and the age of KIC 11026764 with a precision near 1%, and an accuracy near 2% for the radius and 15% for the age. Continued observations of this star promise to reveal additional oscillation frequencies that will further improve the determination of its fundamental properties., Comment: 16 pages, 6 figures, 4 tables, ApJ in press
Published: 2010
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49. Multiwavelength Observations of Small-Scale Reconnection Events triggered by Magnetic Flux Emergence in the Solar Atmosphere

Author: L. R. Bellot Rubio, Salvo L. Guglielmino, Guillaume Aulanier, S. Kamio, S. Vargas Domínguez, Francesca Zuccarello, Università degli studi di Catania = University of Catania (Unict), Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, University College of London [London] (UCL), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and Max-Planck-Gesellschaft
Subjects: Physics, Sun: magnetic topology, Field (physics), Field line, Astrophysics::High Energy Astrophysical Phenomena, Sun: chromosphere, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Magnetic reconnection, Astrophysics, Magnetic flux, Atmosphere, Atmosphere of Earth, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sun: activity, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Event (particle physics), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The interaction between emerging magnetic flux and the pre-existing ambient field has become a "hot" topic for both numerical simulations and high-resolution observations of the solar atmosphere. The appearance of brightenings and surges during episodes of flux emergence is believed to be a signature of magnetic reconnection processes. We present an analysis of a small-scale flux emergence event in NOAA 10971, observed simultaneously with the Swedish 1-m Solar Telescope on La Palma and the \emph{Hinode} satellite during a joint campaign in September 2007. Extremely high-resolution G-band, H$\alpha$, and \ion{Ca}{2} H filtergrams, \ion{Fe}{1} and \ion{Na}{1} magnetograms, EUV raster scans, and X-ray images show that the emerging region was associated with chromospheric, transition region and coronal brightenings, as well as with chromospheric surges. We suggest that these features were caused by magnetic reconnection at low altitude in the atmosphere. To support this idea, we perform potential and linear force-free field extrapolations using the FROMAGE service. The extrapolations show that the emergence site is cospatial with a 3D null point, from which a spine originates. This magnetic configuration and the overall orientation of the field lines above the emerging flux region are compatible with the structures observed in the different atmospheric layers, and remain stable against variations of the force-free field parameter. Our analysis supports the predictions of recent 3D numerical simulations that energetic phenomena may result from the interaction between emerging flux and the pre-existing chromospheric and coronal field., Comment: In press for ApJ
Published: 2010
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50. The field high-amplitude SX Phe variable BL Cam: Results from a multisite photometric campaign: II. Evidence of a binary - Possibly triple - System

Author: M. Helvaci, M. Blauzek, V. Casanova, J. Michelet, G. Santacana, J. P. Sareyan, L. Kotková, A.-Y. Zhou, Hana Kučáková, S. Fauvaud, I. Scheggia, A. Avdibegovic, J. J. Rives, Petr Zasche, A. Nava-Vega, F. Fumagalli, M. Alvarez, C. Ulusoy, K. Truparová, J. Kliner, P. van Cauteren, B. Yasarsoy, Eric G. Hintz, Raoul Behrend, B. H. Granslo, L. Král, Cahit Yeşilyaprak, J. A. Farrell, S. Bartošíková, M. J. López-González, Patricia Lampens, M. Vilášek, Marek Wolf, F. Van Den Abbeel, G. Klingenberg, K. A. Graham, R. Kocián, I. Ribas, H. Wücher, Raul Michel, M. Fauvaud, John H. Simonetti, F. J. Aceituno, M. P. Nicholson, E. Rodriguez, J.-M. Vugnon, O. Trondal, L. Fox-Machado, Ege Üniversitesi, Observatoire du Bois de Bardon, Groupe européen d’observation stellaire (GEOS), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Institut de Ciencies de l'Espai (ICE), Instituto de Astrofisica de Andalucia, CSIC (IAA), Koninklijke Sterrenwacht van België, Variable Star Section, Norwegian Astronomical Society, Sulphur Flats Observatory, Martin Observatory, Physics Dep., Virginia Polytechnic Institute & State University, Blacksburg, Astronomical Institute, Charles University, National Astronomical Observatoires-CAS, Observatorio Astronómico Nacional, Instituto de Astronomía, Universidad Nacional Autónoma de México, Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Societá Astronomica Le pleiadi, Observatoire des Trois Korrigans, Department of Physics and Astronomy, Brigham Young University, Beersel Hills Observatory, Department of Physics, Akdeniz University, Department of Physics, Ataturk University, American Association of Variable Star Observers (AAVSO), Project Eridanus, Observatory and Planetarium of Johann Palisa, Club d'Astronomie Lyon Ampéré [Vaulx-en-Velin] (CALA), Club Eclipse : Club d'Etudes du Ciel, de la Lune, des Instruments, des Planètes, du Soleil et des Etoiles..., Astronomical Institute, Academy of Sciences, Ege University Observatory, Vesqueville Observatory, and Observatoire Astronomique de l'Université de Genève
Subjects: Physics, Stars: individual: BL Camelopardalis, Stars: variables: ? Scuti, education.field_of_study, Cepheid variable, Population, Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Stars, Orbit, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Stars: oscillations, Binaries: general, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Maxima, Instability strip, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), Techniques: photometric
Abstract: Short-period high-amplitude pulsating stars of Population I ($\delta$ Sct stars) and II (SX Phe variables) exist in the lower part of the classical (Cepheid) instability strip. Most of them have very simple pulsational behaviours, only one or two radial modes being excited. Nevertheless, BL Cam is a unique object among them, being an extreme metal-deficient field high-amplitude SX Phe variable with a large number of frequencies. Based on a frequency analysis, a pulsational interpretation was previously given. aims heading (mandatory) We attempt to interpret the long-term behaviour of the residuals that were not taken into account in the previous Observed-Calculated (O-C) short-term analyses. methods heading (mandatory) An investigation of the O-C times has been carried out, using a data set based on the previous published times of light maxima, largely enriched by those obtained during an intensive multisite photometric campaign of BL Cam lasting several months. results heading (mandatory) In addition to a positive (161 $\pm$ 3) x 10$^{-9}$ yr$^{-1}$ secular relative increase in the main pulsation period of BL Cam, we detected in the O-C data short- (144.2 d) and long-term ($\sim$ 3400 d) variations, both incompatible with a scenario of stellar evolution. conclusions heading (mandatory) Interpreted as a light travel-time effect, the short-term O-C variation is indicative of a massive stellar component (0.46 to 1 M$_{\sun}$) with a short period orbit (144.2 d), within a distance of 0.7 AU from the primary. More observations are needed to confirm the long-term O-C variations: if they were also to be caused by a light travel-time effect, they could be interpreted in terms of a third component, in this case probably a brown dwarf star ($\geq$ 0.03 \ M$_{\sun}$), orbiting in $\sim$ 3400 d at a distance of 4.5 AU from the primary., Comment: 7 pages, 5 figures, accepted for publication in A&A
Published: 2010
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