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46 results on '"High Altitude Observatory (HAO)"'

1. A MULTI-SITE CAMPAIGN TO MEASURE SOLAR-LIKE OSCILLATIONS IN PROCYON. II. MODE FREQUENCIES

Author: D. Sosnowska, William J. Chaplin, Hiroyasu Ando, Sylvaine Turck-Chièze, R. P. Butler, T. Appourchaux, Tiago L. Campante, T. H. Dall, J. C. Lebrun, Rafael A. García, Gabrielle Berthomieu, Rosario Cosentino, Saskia Hekker, Silvio Leccia, M. Hartmann, S. Frandsen, B. Mosser, K. Brogaard, Michael Endl, Sabine Reffert, A. P. Hatzes, Jørgen Christensen-Dalsgaard, Christoffer Karoff, Simon J. O'Toole, J. Lundgreen-Nielsen, Janine Provost, Frank Grundahl, E. Michel, László L. Kiss, M. Bazot, H. Bruntt, S. Benatti, Caroline Barban, T. S. Metcalfe, P. Eggenberger, M. Martic, Fabien Carrier, Jean-Loup Bertaux, Robert A. Wittenmyer, B. Sato, Hideyuki Izumiura, Timothy R. Bedding, Eric Stempels, J. H. M. M. Schmitt, Riccardo Claudi, L. Glowienka, Eiji Kambe, Hans Kjeldsen, Torben Arentoft, Alfio Bonanno, Sydney Institute for Astronomy (SIfA), The University of Sydney, Danish AsteroSeismology Centre (DASC), Aarhus University [Aarhus], Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), School of Physics and Astronomy [Birmingham], University of Birmingham [Birmingham], 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), Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Paris (OP), 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, 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 Terrestrial Magnetism [Carnegie Institution], Carnegie Institution for Science, 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), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Anglo-Australian Observatory (AAO), Okayama Astrophysical Observatory (OAO), National Astronomical Observatory of Japan (NAOJ), Global Edge Institute, Tokyo Institute of Technology [Tokyo] (TITECH), Thüringer Landessternwarte Tautenburg (TLS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), 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), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), HELIOS - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), INAF - Osservatorio Astronomico di Padova (OAPD), INAF - Osservatorio Astronomico di Capodimonte (OAC), Department of Physics and Astronomy [Uppsala], Uppsala University, European Southern Observatory (ESO), Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), University of New South Wales [Sydney] (UNSW), McDonald Observatory, University of Texas at Austin [Austin], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg] = Heidelberg University, Sydney Institute for Astronomy ( SIfA ), The University of Sydney [Sydney], Danish AsteroSeismology Centre ( DASC ), Centro de Astrofísica da Universidade do Porto ( CAUP ), Universidade do Porto [Porto], Institut d'astrophysique spatiale ( IAS ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), INAF - Osservatorio Astrofisico di Catania ( OACT ), Istituto Nazionale di Astrofisica ( INAF ), 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 ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire de Paris - Site de Paris ( OP ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-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-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Carnegie Institution for Science [Washington], Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), Hungarian Academy of Sciences [Budapest], Anglo-Australian Observatory ( AAO ), Okayama Astrophysical Observatory ( OAO ), National Astronomical Observatory of Japan ( NAOJ ), National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Tokyo Institute of Technology [Tokyo] ( TITECH ), Thüringer Landessternwarte Tautenburg ( TLS ), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides ( CASSIOPEE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire de Haute-Provence ( OHP ), Institut Pythéas ( OSU PYTHEAS ), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture ( IRSTEA ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture ( IRSTEA ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Centre National de la Recherche Scientifique ( CNRS ), HEPPI - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -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 de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), Universita degli Studi di Padova = University of Padua = Université de Padoue, INAF - Osservatorio Astronomico di Padova ( OAPD ), INAF - Osservatorio Astronomico di Capodimonte ( OAC ), European Southern Observatory ( ESO ), Katholieke Universiteit Leuven ( KU Leuven ), Observatoire Astronomique de l'Université de Genève ( ObsGE ), Université de Genève ( UNIGE ), University of New South Wales [Sydney] ( UNSW ), High Altitude Observatory ( HAO ), National Center for Atmospheric Research [Boulder] ( NCAR ), Landessternwarte Königstuhl [ZAH] ( LSW ), Universität Heidelberg [Heidelberg], Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), 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), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Universita degli Studi di Padova, Université de Genève (UNIGE), Universidade do Porto, 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), and 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)
Subjects: Offset (computer science), Oscillations, Granulation, FOS: Physical sciences, Lifetimes, Astrophysics, 01 natural sciences, Asteroseismology, Stellar Oscillations, Photometry, P-Modes, 0103 physical sciences, Solar-like oscillations, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, geography, [ PHYS.ASTR.SR ] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], geography.geographical_feature_category, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Procyon A, Multi site, Sun, Spectral density, Centroid, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Stars, Corot, Data Reduction, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Ridge, stars: oscillations, stars: individual (Procyon A), [ SDU.ASTR.SR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
Abstract: We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with eleven telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called echelle diagram reveals two clear ridges that we identify with even and odd values of the angular degree (l=0 and 2, and l=1 and 3, respectively). We interpret a strong, narrow peak at 446 muHz that lies close to the l=1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of about 1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29 +0.55/-0.49 days, which is significantly shorter than the 2-4 days seen in the Sun., Comment: accepted for publication in ApJ
Published: 2010
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2. Age dating of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi

Author: William J. Chaplin, Aldo M. Serenelli, Andrea Miglio, Thierry Morel, J. Ted Mackereth, Fiorenzo Vincenzo, Hans Kjeldsen, Sarbani Basu, Warrick H. Ball, Amalie Stokholm, Kuldeep Verma, Jakob Rørsted Mosumgaard, Victor Silva Aguirre, Anwesh Mazumdar, Pritesh Ranadive, H. M. Antia, Yveline Lebreton, Joel Ong, Thierry Appourchaux, Timothy R. Bedding, Jørgen Christensen-Dalsgaard, Orlagh Creevey, Rafael A. García, Rasmus Handberg, Daniel Huber, Steven D. Kawaler, Mikkel N. Lund, Travis S. Metcalfe, Keivan G. Stassun, Michäel Bazot, Paul G. Beck, Keaton J. Bell, Maria Bergemann, Derek L. Buzasi, Othman Benomar, Diego Bossini, Lisa Bugnet, Tiago L. Campante, Zeynep Çelik Orhan, Enrico Corsaro, Lucía González-Cuesta, Guy R. Davies, Maria Pia Di Mauro, Ricky Egeland, Yvonne P. Elsworth, Patrick Gaulme, Hamed Ghasemi, Zhao Guo, Oliver J. Hall, Amir Hasanzadeh, Saskia Hekker, Rachel Howe, Jon M. Jenkins, Antonio Jiménez, René Kiefer, James S. Kuszlewicz, Thomas Kallinger, David W. Latham, Mia S. Lundkvist, Savita Mathur, Josefina Montalbán, Benoit Mosser, Andres Moya Bedón, Martin Bo Nielsen, Sibel Örtel, Ben M. Rendle, George R. Ricker, Thaíse S. Rodrigues, Ian W. Roxburgh, Hossein Safari, Mathew Schofield, Sara Seager, Barry Smalley, Dennis Stello, Róbert Szabó, Jamie Tayar, Nathalie Themeßl, Alexandra E. L. Thomas, Roland K. Vanderspek, Walter E. van Rossem, Mathieu Vrard, Achim Weiss, Timothy R. White, Joshua N. Winn, Mutlu Yıldız, European Commission, European Research Council, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Generalitat de Catalunya, Chaplin W.J., Serenelli A.M., Miglio A., Morel T., Mackereth J.T., Vincenzo F., Kjeldsen H., Basu S., Ball W.H., Stokholm A., Verma K., Mosumgaard J.R., Silva Aguirre V., Mazumdar A., Ranadive P., Antia H.M., Lebreton Y., Ong J., Appourchaux T., Bedding T.R., Christensen-Dalsgaard J., Creevey O., Garcia R.A., Handberg R., Huber D., Kawaler S.D., Lund M.N., Metcalfe T.S., Stassun K.G., Bazot M., Beck P.G., Bell K.J., Bergemann M., Buzasi D.L., Benomar O., Bossini D., Bugnet L., Campante T.L., Orhan Z.C., Corsaro E., Gonzalez-Cuesta L., Davies G.R., Di Mauro M.P., Egeland R., Elsworth Y.P., Gaulme P., Ghasemi H., Guo Z., Hall O.J., Hasanzadeh A., Hekker S., Howe R., Jenkins J.M., Jimenez A., Kiefer R., Kuszlewicz J.S., Kallinger T., Latham D.W., Lundkvist M.S., Mathur S., Montalban J., Mosser B., Bedon A.M., Nielsen M.B., Ortel S., Rendle B.M., Ricker G.R., Rodrigues T.S., Roxburgh I.W., Safari H., Schofield M., Seager S., Smalley B., Stello D., Szabo R., Tayar J., Themessl N., Thomas A.E.L., Vanderspek R.K., van Rossem W.E., Vrard M., Weiss A., White T.R., Winn J.N., Yildiz M., Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Psychology, St John's University, Institute of Space Sciences [Barcelona] (ICE-CSIC), Spanish National Research Council [Madrid] (CSIC), School of Physics and Astronomy, University of Birmingham [Birmingham], Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), Danish AsteroSeismology Centre (DASC), Aarhus University [Aarhus], Department of Astronomy, Yale University [New Haven], Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), 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), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Sydney Institute for Astronomy (SIfA), The University of Sydney, 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), Research institute of Computer Vision and Robotics [Girona] (VICOROB), Universitat de Girona (UdG), Department of Physics and Astronomy [Aarhus], Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], 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), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), 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), NASA Ames Research Center (ARC), Centre for Automation and Robotics (CAR), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad Politécnica de Madrid (UPM), Kiepenheuer-Institut für Sonnenphysik (KIS), Stellar Astrophysics Centre [Aarhus] (SAC), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Département des Sciences et Gestion de l'Environnement/Océanologie [Liège], Université de Liège, Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), High Speed Networks Laboratory, Dept. of Telecommunications and Media Informatics, Budapest University of Technology and Economics [Budapest] (BME), Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Observatoire de Paris, Université Paris sciences et lettres (PSL), Ege Üniversitesi, CERFACS [Toulouse], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Universidad Politécnica de Madrid (UPM)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Milky Way, Population, GAIA, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, MASS, CHEMICAL-COMPOSITION, Q1, 01 natural sciences, Asteroseismology, 0103 physical sciences, QB460, Satellite galaxy, STELLAR HALOES, Astrophysics::Solar and Stellar Astrophysics, 10. No inequality, education, 010303 astronomy & astrophysics, QB600, QC, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Dwarf galaxy, QB, Physics, [PHYS]Physics [physics], education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], ACCRETION HISTORY, Astronomy and Astrophysics, DISC, Astrophysics - Astrophysics of Galaxies, Galaxy, MODEL, Stars, Astrophysics - Solar and Stellar Astrophysics, DARK-MATTER HALOES, ROTATION, Halo, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], SOLAR-LIKE OSCILLATIONS, QB799
Abstract: This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). et al., Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies. Although these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to date precisely the age at which any one merger occurred. Recent results have revealed a population of stars that were accreted via the collision of a dwarf galaxy, called Gaia–Enceladus, leading to substantial pollution of the chemical and dynamical properties of the Milky Way. Here we identify the very bright, naked-eye star ν Indi as an indicator of the age of the early in situ population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be 11.0±0.7 (stat) ±0.8 (sys) billion years. The star bears hallmarks consistent with having been kinematically heated by the Gaia–Enceladus collision. Its age implies that the earliest the merger could have begun was 11.6 and 13.2 billion years ago, at 68% and 95% confidence, respectively. Computations based on hierarchical cosmological models slightly reduce the above limits., J.M. acknowledge support from the ERC Consolidator Grant funding scheme (project ASTEROCHRONOMETRY, grant agreement number 772293). A.M.S. is partially supported by the Spanish Government (ESP2017-82674-R) and Generalitat de Catalunya (2017-SGR-1131). T.L.C. acknowledges support from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement number 792848 (PULSATION). K.J.B., S.H., J.S.K. and N.T. are supported by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement number 338251 (StellarAges). E.C. is funded by the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement number 664931. L.G.-C. acknowledges support from the MINECO FPI-SO doctoral research project SEV-2015-0548-17-2 and predoctoral contract BES-2017-082610. S.M. acknowledges support from the Spanish ministry through the Ramon y Cajal fellowship number RYC-2015-17697. This work was supported by FEDER through COMPETE2020 (POCI-01-0145-FEDER-030389. A.M.B. acknowledges funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 749962 (project THOT).
Published: 2020
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3. TESS asteroseismology of the known red-giant host stars HD 212771 and HD 203949

Author: Filipe Pereira, S. G. Sousa, Daniel Huber, S. Stock, James S. Kuszlewicz, Marc Hon, Mário J. P. F. G. Monteiro, Stephen R. Kane, Rafael A. García, Vardan Adibekyan, Tiago L. Campante, Sabine Reffert, Dennis Stello, Zeynep Çelik Orhan, Guy R. Davies, Martin Bo Nielsen, Timothy R. Bedding, Mutlu Yildiz, Benard Nsamba, Jørgen Christensen-Dalsgaard, Elisa Delgado Mena, H. M. Antia, Sibel Örtel, Maria Tsantaki, Victor Silva Aguirre, Rasmus Handberg, Miles Lucas, Margarida S. Cunha, Sarbani Basu, Savita Mathur, Enrico Corsaro, Nicolas Nardetto, William J. Chaplin, Warrick H. Ball, Mathieu Vrard, Hans Kjeldsen, Jacob L. Bean, Travis S. Metcalfe, Benoit Mosser, Keivan G. Stassun, Aldo Serenelli, Steven D. Kawaler, Margaret C. Turnbull, Mikkel N. Lund, Marc H. Pinsonneault, Dimitri Veras, Andrea Miglio, Diego Bossini, 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), 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), Institute of Space Sciences [Barcelona] (ICE-CSIC), Spanish National Research Council [Madrid] (CSIC), Department of Astronomy, Yale University [New Haven], Sydney Institute for Astronomy (SIfA), The University of Sydney, Department of Physics and Astronomy [Aarhus], Aarhus University [Aarhus], Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Stellar Astrophysics Centre [Aarhus] (SAC), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Observatoire de Paris, Université Paris sciences et lettres (PSL), Department of Psychology, St John's University, Danish AsteroSeismology Centre (DASC), School of Physics and Astronomy, University of Birmingham [Birmingham], Instituto de Patologia e Imunologia Molecular, Universidade do Porto, 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 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), Universität Heidelberg [Heidelberg] = Heidelberg University, Universidade do Porto = University of Porto, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Gemini (LG), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL), Universidade do Porto [Porto], and Ege Üniversitesi
Subjects: 010504 meteorology & atmospheric sciences, Red giant, Star (game theory), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Asteroseismology, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Exoplanets, Astronomy and Astrophysics, Exoplanet, Stars, Evolved stars, Amplitude, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Orhan, Zeynep Celik/0000-0002-9424-2339; Serenelli, Aldo/0000-0001-6359-2769; Monteiro, Mario J. P. F. G./0000-0003-0513-8116; Huber, Daniel/0000-0001-8832-4488; Adibekyan, Vardan/0000-0002-0601-6199; Reffert, Sabine/0000-0002-0460-8289; Stock, Stephan/0000-0002-1166-9338; Stassun, Keivan/0000-0002-3481-9052; Cunha, Margarida/0000-0001-8237-7343; Kuszlewicz, James/0000-0002-3322-5279; Lund, Mikkel Norup/0000-0001-9214-5642; Mathur, Savita/0000-0002-0129-0316; Nielsen, Martin Bo/0000-0001-9169-2599; Mosser, Benoit/0000-0002-7547-1208; Pereira, Filipe/0000-0002-2157-7146; Lucas, Miles/0000-0001-6341-310X; miglio, andrea/0000-0001-5998-8533; Ball, Warrick/0000-0002-4773-1017; Basu, Sarbani/0000-0002-6163-3472; Veras, Dimitri/0000-0001-8014-6162; Handberg, Rasmus/0000-0001-8725-4502; Christensen-Dalsgaard, Jorgen/0000-0001-5137-0966; Delgado Mena, Elisa/0000-0003-4434-2195, WOS: 000498546800001, The Transiting Exoplanet Survey Satellite (TESS) is performing a near all-sky survey for planets that transit bright stars. in addition, its excellent photometric precision enables asteroseismology of solar-type and red-giant stars, which exhibit convection-driven, solar-like oscillations. Simulations predict that TESS will detect solar-like oscillations in nearly 100 stars already known to host planets. in this paper, we present an asteroseismic analysis of the known red-giant host stars HD;212771 and HD;203949, both systems having a long-period planet detected through radial velocities. These are the first detections of oscillations in previously known exoplanet-host stars by TESS, further showcasing the mission?s potential to conduct asteroseismology of red-giant stars. We estimate the fundamental properties of both stars through a grid-based modeling approach that uses global asteroseismic parameters as input. We discuss the evolutionary state of HD;203949 in depth and note the large discrepancy between its asteroseismic mass (M-* = 1.23 0.15 MM* = 1.00 0.16 M if in the clump) and the mass quoted in the discovery paper (M-* = 2.1 0.1 M), implying a change >30% in the planet?s mass. Assuming HD;203949 to be in the clump, we investigate the planet?s past orbital evolution and discuss how it could have avoided engulfment at the tip of the red-giant branch. Finally, HD;212771 was observed by K2 during its Campaign 3, thus allowing for a preliminary comparison of the asteroseismic performances of TESS and K2. We estimate the ratio of the observed oscillation amplitudes for this star to be, NASA Explorer ProgramNational Aeronautics & Space Administration (NASA); ESA PRODEXEuropean Space Agency [PEA 4000119301]; Stellar Astrophysics Centre (SAC) - Danish National Research Foundation [DNRF106]; European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grantEuropean Union (EU) [792848, 664931]; FCT/MCTESPortuguese Foundation for Science and Technology [UID/FIS/04434/2019]; FCTPortuguese Foundation for Science and Technology [PTDC/FIS-AST/30389/2017, PTDC/FIS-AST/28953/2017, PTDC/FIS-AST/32113/2017, CEECIND/02619/2017, IF/00650/2015/CP1273/CT0001, IF/00028/2014/CP1215/CT0002]; FEDER through COMPETE2020 [POCI-01-0145-FEDER-030389, POCI-01-0145-FEDER-028953, POCI-01-0145-FEDER-032113]; National Science Foundation under the Kavli Institute for Theoretical Physics program "Better Stars, Better Planets" [NSF PHY-1748958]; European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant [338251]; ESA PRODEX programme; CNES through the PLATO grants; Spanish GovernmentSpanish Government [ESP2017-82674-R]; Generalitat de CatalunyaGeneralitat de Catalunya [2017-SGR-1131]; STFC via an Ernest Rutherford Fellowship [ST/P003850/1]; NSFNational Science Foundation (NSF) [AST-1514676]; NASANational Aeronautics & Space Administration (NASA) [NNX16AI09G]; Spanish Ministry through the Ramon y Cajal fellowship [RYC-2015-17697]; NYUAD Institute [G1502]; DFGGerman Research Foundation (DFG) [SPP 1992, RE 2694/5-1]; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TUBITAK:118F352]; National Aeronautics and Space Administration through the TESS Guest Investigator Program [80NSSC18K1585, 80NSSC19K0379]; European Social Fund via the Lithuanian Science Council [09.3.3-LMT-K-712-01-0103], This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. Funding for the TESS Asteroseismic Science Operations Center at Aarhus University is provided by ESA PRODEX (PEA 4000119301) and Stellar Astrophysics Centre (SAC), funded by the Danish National Research Foundation (Grant agreement No.: DNRF106). the project leading to this publication has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No..792848 (PULSATION). This work was supported by FCT/MCTES through national funds (UID/FIS/04434/2019). This work was supported by FCT through national funds (PTDC/FIS-AST/30389/2017, PTDC/FIS-AST/28953/2017, and PTDC/FIS-AST/32113/2017) and by FEDER through COMPETE2020 (POCI-01-0145-FEDER-030389, POCI-01-0145-FEDER-028953, and POCI-01-0145-FEDER-032113). This research was supported in part by the National Science Foundation under grant No.NSF PHY-1748958 through the Kavli Institute for Theoretical Physics program "Better Stars, Better Planets". the research leading to the presented results has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No..338251 (StellarAges). E.C.is funded by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No..664931. M.N.L.acknowledges support from the ESA PRODEX programme. B.M.and R.A.G. acknowledge the support received from CNES through the PLATO grants. A. S.is partially supported by grants ESP2017-82674-R (Spanish Government) and 2017-SGR-1131 (Generalitat de Catalunya). D.V.gratefully acknowledges the support of the STFC via an Ernest Rutherford Fellowship (grant ST/P003850/1). V. A.and S.G.S. acknowledge support from FCT through Investigador FCT contracts No..IF/00650/2015/CP1273/CT0001 and No..IF/00028/2014/CP1215/CT0002, respectively. S. B. acknowledges NSF grant AST-1514676 and NASA grant NNX16AI09G. S.M..acknowledges support from the Spanish Ministry through the Ramon y Cajal fellowship No. RYC-2015-17697. M.B.N..acknowledges support from NYUAD Institute grant G1502. S.R..acknowledges support from the DFG priority program SPP 1992 "Exploring the Diversity of Extrasolar Planets (RE 2694/5-1)". M.Y., Z.C.O., and S. O. acknowledge the Scientific and Technological Research Council of Turkey (TUBITAK:118F352). D.H. acknowledges support by the National Aeronautics and Space Administration (80NSSC18K1585, 80NSSC19K0379) awarded through the TESS Guest Investigator Program. M.S.C. is supported in the form of a work contract funded by FCT (CEECIND/02619/2017). H.K. acknowledges support from the European Social Fund via the Lithuanian Science Council grant No. 09.3.3-LMT-K-712-01-0103.
Published: 2019
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4. The statistical dependence of auroral absorption on geomagnetic and solar wind parameters

Author: Emma Woodfield, Michael Kosch, Farideh Honary, Andrew Kavanagh, Andrew Senior, S. R. Marple, Ian McCrea, EGU, Publication, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Department of Communications Systems, Honorary Reseach Fellow, University of Natal, Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), and Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, 0103 physical sciences, Substorm, Riometer, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, Solar wind, lcsh:Geophysics. Cosmic physics, Earth's magnetic field, 13. Climate action, Space and Planetary Science, Local time, Physics::Space Physics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, Ionosphere, lcsh:Physics
Abstract: Data from the Imaging Riometer for Ionospheric Studies (IRIS) at Kilpisjärvi, Finland, have been compiled to form statistics of auroral absorption based on seven years of observations. In a previous study a linear relationship between the logarithm of the absorption and the Kp index provided a link between the observations of precipitation with the level of geomagnetic activity. A better fit to the absorption data is found in the form of a quadratic in Kp for eight magnetic local time sectors. Past statistical investigations of absorption have hinted at the possibility of using the solar wind velocity as a proxy for the auroral absorption, although the lack of available satellite data made such an investigation difficult. Here we employ data from the solar wind monitors, WIND and ACE, and derive a linear relationship between the solar wind velocity and the cosmic noise absorption at IRIS for the same eight magnetic local time sectors. As far as the authors are aware this is the first time that in situ measurements of the solar wind velocity have been used to create a direct link with absorption on a statistical basis. The results are promising although, it is clear that some other factor is necessary in providing reliable absorption predictions. Due to the substorm related nature of auroral absorption, this is likely formed by the recent time history of the geomagnetic activity, or by some other indicator of the energy stored within the magnetotail. For example, a dependence on the southward IMF (interplanetary magnetic field) is demonstrated with absorption increasing with successive decreases in Bz; a northward IMF appears to have little effect and neither does the eastward component, By. Key words. Magnetospheric physics (energetic particles, precipitating; solar wind-magnetosphere interactions) – Ionosphere (modeling and forecasting)
Published: 2018

5. Where does the Thermospheric Ionospheric GEospheric Research (TIGER) Program go?

Author: Jens Berdermann, Gaël Cessateur, Ch. Jacobi, L. Ciraolo, Gerhard Schmidtke, R. Hammer, W. K. Tobiska, Alexander Gottwald, Stanley C. Solomon, Robert Schäfer, Wolfgang Schmidt, S.V. Avakyan, Sandro M. Radicella, Norbert Jakowski, Volker Bothmer, Matthieu Kretzschmar, Gérard Thuillier, Thierry Dudok de Wit, Seth Wieman, Thomas N. Woods, Francis G. Eparvier, Leonid Didkovsky, Marcel Pfeifer, Jean Lilensten, M. Haberreiter, Publica, Fraunhofer-Institut für Physikalische Messtechnik (Fraunhofer IPM), S.I. Vavilov State Optical Institute, DLR Institute of Communications and Navigation [Neustrelitz], German Aerospace Center (DLR), Georg-August-University [Göttingen], Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC), Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), University of Southern California (USC), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisch-Technische Bundesanstalt [Berlin] (PTB), Kiepenheuer-Institut für Sonnenphysik (KIS), Universität Leipzig [Leipzig], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Environment, Technologies, Pacific Palisades, European Project: 313188,EC:FP7:SPA,FP7-SPACE-2012-1,SOLID(2012), Fraunhofer Institute for Physical Measurement Techniques (Fraunhofer IPM), Fraunhofer (Fraunhofer-Gesellschaft), Georg-August-University = Georg-August-Universität Göttingen, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-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)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Universität Leipzig, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Space Environment, Technologies [Pacific Palisades], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])
Subjects: UV/EUV solar spectral irradiance, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Atmospheric Science, Committee on Space Research, Total electron content, Meteorology, Modeling, Irradiance, Aerospace Engineering, Astronomy and Astrophysics, Space weather, Solar physics, Solar irradiance, 7. Clean energy, Geophysics, 13. Climate action, Space and Planetary Science, Extreme ultraviolet, Calibration, General Earth and Planetary Sciences, Environmental science, UV / EUV Solar Spectral Irradiance, Ionosphere, Instrumentation, Remote sensing
Abstract: International audience; At the 10th Thermospheric Ionospheric GEospheric Research (TIGER/COSPAR) symposium held in Moscow in 2014 the achievements from the start of TIGER in 1998 were summarized. During that period, great progress was made in measuring, understanding, and modeling the highly variable UV-Soft X-ray (XUV) solar spectral irradiance (SSI), and its effects on the upper atmosphere. However, after more than 50 years of work the radiometric accuracy of SSI observation is still an issue and requires further improvement. Based on the extreme ultraviolet (EUV) data from the SOLAR/SolACES, and SDO/EVE instruments, we present a combined data set for the spectral range from 16.5 to 105.5 nm covering a period of 3.5 years from 2011 through mid of 2014. This data set is used in ionospheric modeling of the global total electron content (TEC), and in validating EUV SSI modeling. For further investigations the period of 3.5 years is being extended to about 12 years by including data from SOHO/SEM and TIMED/SEE instruments. Similarly, UV data are used in modeling activities. After summarizing the results, concepts are proposed for future real-time SSI measurements with in-flight calibration as experienced with the ISS SOLAR payload, for the development of a space weather camera for observing and investigating space weather phenomena in real-time, and for providing data sets for SSI and climate modeling. Other planned topics are the investigation of the relationship between solar EUV/UV and visible/near-infrared emissions, the impact of X-rays on the upper atmosphere, the development of solar EUV/UV indices for different applications, and establishing a shared TIGER data system for EUV/UV SSI data distribution and real-time streaming, also taking into account the achievements of the FP7 SOLID (First European SOLar Irradiance Data Exploitation) project. - For further progress it is imperative that coordinating activities in this special field of solar-terrestrial relations and solar physics is emphasized.
Published: 2015
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6. Metallicity effect on stellar granulation detected from oscillating red giants in open clusters

Author: Patrick Gaulme, Marc H. Pinsonneault, S. Mathur, Chen Jiang, Christian Nitschelm, Keivan G. Stassun, Dennis Stello, Jamie Tayar, Regner Trampedach, E. Corsaro, Rafael A. García, David Salabert, INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Sydney Institute for Astronomy (SIfA), The University of Sydney, Universidad de La Laguna [Tenerife - SP] (ULL), and Instituto de Astrofisica de Canarias (IAC)
Subjects: oscillations [stars], Stellar mass, Red giant, Metallicity, statistical [methods], fundamental parameters [stars], FOS: Physical sciences, KEPLER, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, SCALING RELATIONS, 01 natural sciences, Asteroseismology, methods: numerical, GRAVITY, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, HYDRODYNAMICAL SIMULATIONS, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, methods: statistical, 010308 nuclear & particles physics, stars: late-type, Stellar atmosphere, Astronomy and Astrophysics, numerical [methods], open clusters and associations: general, Surface gravity, ASTEROSEISMOLOGY, Stars, VARIABILITY, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, CONVECTION, DIGITAL SKY SURVEY, MICROVARIABILITY, late-type [stars], stars: oscillations, stars: fundamental parameters, general [open clusters and associations], Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], STARS, Open cluster
Abstract: The effect of metallicity on the granulation activity in stars is still poorly understood. Available spectroscopic parameters from the updated APOGEE-\textit{Kepler} catalog, coupled with high-precision photometric observations from NASA's \textit{Kepler} mission spanning more than four years of observation, make oscillating red giant stars in open clusters crucial testbeds. We determine the role of metallicity on the stellar granulation activity by discriminating its effect from that of different stellar properties such as surface gravity, mass, and temperature. We analyze 60 known red giant stars belonging to the open clusters NGC 6791, NGC 6819, and NGC 6811, spanning a metallicity range from [Fe/H] $\simeq -0.09$ to $0.32$. The parameters describing the granulation activity of these stars and their $\nu_\mathrm{max}$, are studied by considering the different masses, metallicities, and stellar evolutionary stages. We derive new scaling relations for the granulation activity, re-calibrate existing ones, and identify the best scaling relations from the available set of observations. We adopted the Bayesian code DIAMONDS for the analysis of the background signal in the Fourier spectra of the stars. We performed a Bayesian parameter estimation and model comparison to test the different model hypotheses proposed in this work and in the literature. Metallicity causes a statistically significant change in the amplitude of the granulation activity, with a dependency stronger than that induced by both stellar mass and surface gravity. We also find that the metallicity has a significant impact on the corresponding time scales of the phenomenon. The effect of metallicity on the time scale is stronger than that of mass. A higher metallicity increases the amplitude of granulation and meso-granulation signals and slows down their characteristic time scales toward longer periods., Comment: 20 pages, 11 figures, 9 tables. Accepted for publication in A&A
Published: 2017
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7. Lithium abundance and rotation of seismic solar analogues

Author: Tharcísyo Duarte, Devika Kamath, Savita Mathur, Paul G. Beck, M. F. Andersen, Ricky Egeland, Matthieu Castro, H. Van Winckel, D. Montes, S. Mathis, O. L. Creevey, Andrew Tkachenko, P. L. Pallé, J. D. do Nascimento, Rafael A. García, David Salabert, 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), Universidade Federal do Rio Grande do Norte [Natal] (UFRN), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Space Science Institute [Boulder] (SSI), Universidad de La Laguna [Tenerife - SP] (ULL), Instituto de Astrofisica de Canarias (IAC), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Montana State University (MSU), Departamento Fisica de la Tierra, Astronomía y Astrofísica [Madrid], Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), 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), Stellar Astrophysics Centre [Aarhus] (SAC), Aarhus University [Aarhus], CNES GOLF and PLATO grants., ANR-12-BS05-0008,IDEE,Influence Des Etoiles sur les Exoplanètes(2012), European Project: 647383,H2020,ERC-2014-CoG,SPIRE(2015), European Project: 670519,H2020,ERC-2014-ADG,MAMSIE(2016), European Project: 312844,EC:FP7:SPA,FP7-SPACE-2012-1,SPACEINN(2013), European Project: 269194,EC:FP7:PEOPLE,FP7-PEOPLE-2010-IRSES,ASK(2011), 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), Harvard University-Smithsonian Institution, 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: Angular momentum, stars: abundances, fundamental parameters [stars], FOS: Physical sciences, chemistry.chemical_element, Binary number, Stars - general, Astrophysics, asteroseismology, stars: interiors, Rotation, 01 natural sciences, Asteroseismology, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Stellar evolution, stars: general, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, interiors [stars], Stars - interiors, 010308 nuclear & particles physics, general [stars], Astronomy and Astrophysics, Stars - abundances, abundances [stars], Stars, Astrophysics - Solar and Stellar Astrophysics, chemistry, 13. Climate action, Space and Planetary Science, Lithium, stars: fundamental parameters, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stars - fundamental parameters
Abstract: Lithium abundance A(Li) and surface rotation are good diagnostic tools to probe the internal mixing and angular momentum transfer in stars. We explore the relation between surface rotation, A(Li) and age in a sample of seismic solar-analogue (SA) stars and study their possible binary nature. We select a sample of 18 SA observed by the NASA Kepler satellite for an in-depth analysis. Their seismic properties and surface rotation are well constrained from previous studies. About 53 hours of high-resolution spectroscopy were obtained to derive fundamental parameters and A(Li). These values were combined and confronted with seismic masses, radii and ages, as well as surface rotation periods. We identify a total of 6 binary systems. A well-defined relation between A(Li) and rotation was obtained. With models constrained by the characterisation of the individual mode frequencies for single stars, we identify a sequence of three SA with similar mass (~1.1Mo) and stellar ages ranging between 1 to 9 Gyr. Within the realistic estimate of ~7% for the mass uncertainty, we find a good agreement between the measured A(Li) and the predicted A(Li) evolution from a grid of models calculated with the Toulouse-Geneva stellar evolution code, which includes rotational internal mixing, calibrated to reproduce solar chemical properties. We present A(Li) for a consistent spectroscopic survey of SA with a mass of 1.00+/-0.15Mo, and characterised through asteroseismology and surface rotation rates based on Kepler observations. The correlation between A(Li) and P_rot supports the gyrochronological concept for stars younger than the Sun. The consensus between measured A(Li) for solar analogues with model grids, calibrated onto the Sun's chemical properties suggests that these targets share the same internal physics. In this light, the solar Li and rotation rate appear to be normal for a star like the Sun., Comment: Accepted for publications in A&A, 11 pages, 6 figures
Published: 2017
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8. Resonance scattering polarization in the magnetosphere of Mercury

Author: A. López Ariste, R. Manso Sainz, François Leblanc, C. Le Men, Roberto Casini, B. Gelly, Télescope héliographique pour l'étude du magnétisme et des instabilites solaires (THEMIS), Centre National de la Recherche Scientifique (CNRS), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), and Instituto de Astrofisica de Canarias (IAC)
Subjects: 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], Magnetosphere, 01 natural sciences, Atmosphere of Mercury, Polarimetry, 0103 physical sciences, Atom, Emission spectrum, Spectroscopy, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Astronomy, Astronomy and Astrophysics, Mercury, Polarization (waves), Magnetic field, Magnetospheres, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Atomic physics, Exosphere
Abstract: International audience; The conditions of the exosphere of Mercury constitute a prime example of a magnetosphere subject to space weather. We aim at improving the diagnostic of the physical conditions of Na atoms in the exosphere of Mercury, with particular emphasis in the possibility of inferring the magnetic field through polarimetry of the Na D emission lines. We performed spectropolarimetry of the Na D emission lines in the exosphere of Mercury at two different ranges of phases of the planet and interpreted them under present models of resonance scattering polarization applied to the Na atom. We measured successfully the polarization of the Na D2 line while no polarization was seen in D1, as expected. The measured polarization varies with the phase angle but it is roughly a factor two smaller than expected from an isolated emitting atom. Depolarization due to the presence of optical depth explains this factor two and is the most probable explanation for this discrepancy. A framework for the observation of polarization in the emission lines of the exosphere and its interpretation is laid. This opens the possibility to use these measurements for diagnostic of the physical conditions in the exosphere of Mercury, and eventually to infer the magnetic field of Mercury and its variability from observations made with ground telescopes.
Published: 2012
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9. Mesoscale ionospheric electrodynamics of omega bands determined from ground-based electromagnetic and satellite optical observations

Author: O. Amm, A. Aksnes, J. Stadsnes, N. Østgaard, R. R. Vondrak, G. A. Germany, G. Lu, A. Viljanen, Finnish Meteorological Institute (FMI), Department of Physics and Technology [Bergen] (UiB), University of Bergen (UiB), University of California, NASA Goddard Space Flight Center (GSFC), University of Alabama in Huntsville (UAH), High Altitude Observatory (HAO), and National Center for Atmospheric Research [Boulder] (NCAR)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Mesoscale meteorology, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, Omega, 0103 physical sciences, Substorm, Earth and Planetary Sciences (miscellaneous), Surge, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Pixie, Polar, lcsh:Q, Satellite, Ionosphere, lcsh:Physics
Abstract: We present ground-based electromagnetic data from the MIRACLE and BEAR networks and satellite optical observations from the UVI and PIXIE instruments on the Polar satellite of an omega band event over Northern Scandinavia on 26 June 1998, which occured close to the morning side edge of a substorm auroral bulge. Our analysis of the data concentrates on one omega band period from 03:18-03:27UT, for which we use the method of characteristics combined with an analysis of the UVI and PIXIE data to derive a time series of instantaneous, solely data-based distributions of the mesoscale ionospheric electrodynamic parameters with a 1-min time resolution. In addition, the AMIE method is used to derive global Hall conductance patterns. Our results show that zonally alternating regions of enhanced ionospheric conductances ("tongues") up to ~60S and low conductance regions are associated with the omega bands. The tongues have a poleward extension of ~400km from their base and a zonal extension of ~380km. While they are moving coherently eastward with a velocity of ~770ms-1, the structures are not strictly stationary. The current system of the omega band can be described as a superposition of two parts: one consists of anticlockwise rotating Hall currents around the tongues, along with Pedersen currents, with a negative divergence in their centers. The sign of this system is reversing in the low conductance areas. It causes the characteristic ground magnetic signature. The second part consists of zonally aligned current wedges of westward flowing Hall currents and is mostly magnetically invisible below the ionosphere. This system dominates the field-aligned current (FAC) pattern and causes alternating upward and downward FAC at the flanks of the tongues with maximum upward FAC of ~25µAm-2. The total FAC of ~2MA are comparable to the ones diverted inside a westward traveling surge. Throughout the event, the overwhelming part of the FAC are associated with gradients of the ionospheric conductances, and 66-84% of the FAC are connected with ionospheric Hall currents.
Published: 2005
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10. An extended TRANSCAR model including ionospheric convection: simulation of EISCAT observations using inputs from AMIE

Author: P.-L. Blelly, C. Lathuillère, B. Emery, J. Lilensten, J. Fontanari, D. Alcaydé, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de Planétologie de Grenoble (LPG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), 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: Convection, Atmospheric Science, 010504 meteorology & atmospheric sciences, Field line, Electron precipitation, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Space weather, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Physics::Geophysics, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Flux tube, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Earth's magnetic field, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Polar, lcsh:Q, Ionosphere, lcsh:Physics
Abstract: The TRANSCAR ionospheric model was extended to account for the convection of the magnetic field lines in the auroral and polar ionosphere. A mixed Eulerian-Lagrangian 13-moment approach was used to describe the dynamics of an ionospheric plasma tube. In the present study, one focuses on large scale transports in the polar ionosphere. The model was used to simulate a 35-h period of EISCAT-UHF observations on 16-17 February 1993. The first day was magnetically quiet, and characterized by elevated electron concentrations: the diurnal F2 layer reached as much as 1012m-3, which is unusual for a winter and moderate solar activity (F10.7=130) period. An intense geomagnetic event occurred on the second day, seen in the data as a strong intensification of the ionosphere convection velocities in the early afternoon (with the northward electric field reaching 150mVm-1) and corresponding frictional heating of the ions up to 2500K. The simulation used time-dependent AMIE outputs to infer flux-tube transports in the polar region, and to provide magnetospheric particle and energy inputs to the ionosphere. The overall very good agreement, obtained between the model and the observations, demonstrates the high ability of the extended TRANSCAR model for quantitative modelling of the high-latitude ionosphere; however, some differences are found which are attributed to the precipitation of electrons with very low energy. All these results are finally discussed in the frame of modelling the auroral ionosphere with space weather applications in mind.
Published: 2005

11. On solar protons and polar cap absorption: constraints on an empirical relationship

Author: Ian McCrea, Andrew Kavanagh, Steve R. Marple, Andrew Senior, Farideh Honary, EGU, Publication, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Department of Communication Systems, Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), and Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Proton, Solar zenith angle, Flux, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Cosmic ray, 01 natural sciences, Optics, 0103 physical sciences, Riometer, Earth and Planetary Sciences (miscellaneous), Absorption (electromagnetic radiation), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, business.industry, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, lcsh:QC1-999, Computational physics, lcsh:Geophysics. Cosmic physics, Earth's magnetic field, 13. Climate action, Space and Planetary Science, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, Ionosphere, business, lcsh:Physics
Abstract: A large database of Solar Proton Events (SPE) from the period 1995 to 2001 is used to investigate the relationship between proton flux at geostationary orbit and Cosmic Noise Absorption (CNA) in the auroral zone. The effect of solar illumination on this relationship is studied in a statistical manner by deriving correlation coefficients of integral flux and absorption as a function of solar zenith angle limit, thus both an upper limit on the angle and the best correlated integral flux of protons are determined (energies in excess of 10MeV). By considering the correlation of various energy ranges (from the GOES 8 differential proton flux channels) with CNA the range of proton energies for which the relationship between flux and absorption is best defined is established (15 to 44MeV), thus confirming previous predictions about which proton energy ranges are most effective in giving rise to absorption during Polar Cap Absorption (PCA) events. An empirical relationship between the square root of the integral proton flux and the absorption, measured by the imaging riometer at Kilpisjärvi (IRIS), is determined and departures from linearity and possible causes are examined. Variations in spectral "hardness" and in collision frequency are demonstrated not to be significant causes of the observed departures from a linear relationship. Geomagnetic activity may be a significant factor in changing the relationship between the absorption and the square root of the integral proton flux, although it is concluded that the cause is likely to be more complex than a straightforward dependence on Kp. It is suggested that the most significant factor might be a bias in the absorption estimates imposed by the presence of Solar Radio Emission (SRE), which is not routinely measured at the operating frequency of IRIS, making its precise effect difficult to quantify. SRE is known to be most prevalent under conditions of high solar activity, such as those that might give rise to solar proton events. Key words. Ionosphere (particle precipitation; solar radiation and cosmic ray effects; polar ionosphere)
Published: 2004

12. Effects of energetic electrons on the electrodynamics in the ionosphere

Author: A. Aksnes, J. Stadsnes, G. Lu, N. Østgaard, R. R. Vondrak, D. L. Detrick, T. J. Rosenberg, G. A. Germany, M. Schulz, Department of Physics, Okayama University, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), University of California, NASA Goddard Space Flight Center (GSFC), University of Maryland [College Park], University of Maryland System, University of Alabama in Huntsville (UAH), Lockheed Martin Advanced Technology Laboratories (ATL), and Lockheed Martin Advanced Technology Laboratories
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Energy flux, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Electron, 7. Clean energy, 01 natural sciences, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Earth's magnetic field, 13. Climate action, Space and Planetary Science, Quantum electrodynamics, Physics::Space Physics, Pixie, lcsh:Q, Atomic physics, Ionosphere, Joule heating, lcsh:Physics
Abstract: From the observations by the PIXIE and UVI cameras on board the Polar satellite, we derive global maps of the precipitating electron energy spectra from less than 1keV to 100keV. Based on the electron spectra, we generate instantaneous global maps of Hall and Pedersen conductances. The UVI camera provides good coverage of the lower electron energies contributing most to the Pedersen conductance, while PIXIE captures the high energy component of the precipitating electrons affecting the Hall conductance. By characterizing the energetic electrons from some tens of keV and up to about 100keV using PIXIE X-ray measurements, we will, in most cases, calculate a larger electron flux at higher energies than estimated from a simple extrapolation of derived electron spectra from UVI alone. Instantaneous global conductance maps derived with and without inclusion of PIXIE data have been implemented in the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure, to study the effects of energetic electrons on electrodynamical parameters in the ionosphere. We find that the improved electron spectral characterization using PIXIE data most often results in a larger Hall conductance and a smaller inferred electric field. In some localized regions the increase in the Hall conductance can exceed 100%. On the contrary, the Pedersen conductance remains more or less unaffected by the inclusion of the PIXIE data. The calculated polar cap potential drop may decrease more than 10%, resulting in a reduction of the estimated Joule heating integrated over the Northern Hemisphere by up to 20%. Locally, Joule heating may decrease more than 50% in some regions. We also find that the calculated energy flux by precipitating electrons increases around 5% when including the PIXIE data. Combined with the reduction of Joule heating, this results in a decrease in the ratio between Joule heating and energy flux, sometimes exceeding 25%. An investigation of the relationship between Joule heating and the AE index shows a nearly linear correspondence between the two quantities, in accordance with previous studies. However, we find lower proportionality factors than reported by others when taking geomagnetic conditions into account, ranging between 0.13 and 0.23GW/nT. We also find that the contribution from auroral particles to the energy budget is more important than most previous studies have reported. Key words. Ionosphere (auroral ionosphere; particle precipitation) – Magnetospheric physics (storms and substorms)
Published: 2004

13. Properties of 42 Solar-type Kepler Targets from the Asteroseismic Modeling Portal

Author: M. Di Mauro, Timothy R. White, M. Steslicki, Margarida S. Cunha, Karan Molaverdikhani, T. S. Metcalfe, A. M. Serenelli, Benjamin P. Brown, R. Trampedach, Dennis Stello, William J. Chaplin, Sébastien Deheuvels, Derek Buzasi, R. Simoniello, Anwesh Mazumdar, Guy R. Davies, Timothy R. Bedding, Mário J. P. F. G. Monteiro, Jørgen Christensen-Dalsgaard, Rachel Howe, Mutlu Yildiz, O. L. Creevey, Yvonne Elsworth, David B. Guenther, K. B. MacGregor, Othman Benomar, S. Mathur, Yveline Lebreton, Aliz Derekas, Rafael A. García, Christoffer Karoff, G. Doğan, Haiying Xu, D. Pricopi, Tiago L. Campante, D. Salabert, Josefina Montalbán, Z. Celik, M. D. Suran, M. Gruberbauer, C. Aksoy, J. A. Guzik, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Computational and Information Systems Laboratory (CISL), Stellar Astrophysics Centre [Aarhus] (SAC), Aarhus University [Aarhus], Laboratoire d'Annecy-le-Vieux de Physique Théorique (LAPTH), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), Dept. Electrical and Computer Engineering, University of Minnesota, University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, BIT lab (BIT Lab), Université Galatasaray (GSU), Department of Astronomy and Physics [Halifax], Saint Mary's University [Halifax], Inorgan Chem Lab, 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), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Ege Üniversitesi, Università degli studi di Torino = University of Turin (UNITO), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: oscillations [stars], FOS: Physical sciences, Astrophysics, Type (model theory), stars: interiors, 01 natural sciences, Kepler, methods: numerical, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, stars: evolution, 010303 astronomy & astrophysics, Scaling, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Physics, interiors [stars], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Oscillation, Subgiant, Mode (statistics), Astronomy and Astrophysics, numerical [methods], Radius, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, evolution [stars], Astrophysics::Earth and Planetary Astrophysics, stars: oscillations
Abstract: WOS: 000344141500013, Recently the number of main-sequence and subgiant stars exhibiting solar-like oscillations that are resolved into individual mode frequencies has increased dramatically. While only a few such data sets were available for detailed modeling just a decade ago, the Kepler mission has produced suitable observations for hundreds of new targets. This rapid expansion in observational capacity has been accompanied by a shift in analysis and modeling strategies to yield uniform sets of derived stellar properties more quickly and easily. We use previously published asteroseismic and spectroscopic data sets to provide a uniform analysis of 42 solar-type Kepler targets from the Asteroseismic Modeling Portal. We find that fitting the individual frequencies typically doubles the precision of the asteroseismic radius, mass, and age compared to grid-based modeling of the global oscillation properties, and improves the precision of the radius and mass by about a factor of three over empirical scaling relations. We demonstrate the utility of the derived properties with several applications., NASANational Aeronautics & Space Administration (NASA) [NNX13AC44G, NNX13AE91G]; White Dwarf Research Corporation through the Pale Blue Dot project; Danish National Research FoundationDanmarks Grundforskningsfond [DNRF106]; European Research CouncilEuropean Research Council (ERC) [267864]; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TUBITAK:112T989]; European Commission grant for the SPACEINN project [FP7-SPACE-2012-312844]; NSF Astronomy and Astrophysics postdoctoral fellowshipNational Science Foundation (NSF) [AST 09-02004]; NSFNational Science Foundation (NSF) [PHY 08-21899, PHY 11-25915]; Investigador FCT contract - FCT/MCTES (Portugal); POPH/FSE (EC)European Commission Joint Research CentreEuropean Social Fund (ESF); Hungarian OTKAOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [K83790, KTIA URKUT_10-1-2011-0019]; Lendulet Young Researchers Programme of the Hungarian Academy of Sciences; Janos Bolyai Research Scholarship of the Hungarian Academy of SciencesHungarian Academy of Sciences; City of Szombathely [S-11-1027]; European Community Seventh Framework Programme (FP7) [269194 (IRSES/ASK)]; CNES grant at CEA-Saclay; NIUS programme of HBCSE (TIFR); MICINN grant [AYA2011-24704]; ESF EUROCORES Program EuroGENESIS (MICINN) [EUI2009-04170]; Australian Research CouncilAustralian Research Council; Science and Technology Facilities CouncilScience & Technology Facilities Council (STFC) [ST/J001163/1], We would like to thank Victor Silva Aguirre for helpful discussions. This work was supported in part by NASA grants NNX13AC44G and NNX13AE91G, and by White Dwarf Research Corporation through the Pale Blue Dot project (http://whitedwarf.org/palebluedot/). Computational time on Kraken at the National Institute of Computational Sciences was provided through XSEDE allocation TG-AST090107. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (grant DNRF106). We acknowledge the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement No.: 267864), the Scientific and Technological Research Council of Turkey (TUBITAK:112T989), and a European Commission grant for the SPACEINN project (FP7-SPACE-2012-312844). B.P.B. was supported in part by NSF Astronomy and Astrophysics postdoctoral fellowship AST 09-02004. C.M.S.O. is supported by NSF grant PHY 08-21899 and K.I.T.P. is supported by NSF grant PHY 11-25915. M.S.C. is supported by an Investigador FCT contract funded by FCT/MCTES (Portugal) and POPH/FSE (EC). A.D. has been supported by the Hungarian OTKA grants K83790, KTIA URKUT_10-1-2011-0019 grant, the Lendulet-2009 Young Researchers Programme of the Hungarian Academy of Sciences, the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences and the City of Szombathely under agreement No. S-11-1027. A.D. and R.A.G. acknowledge the support of the European Community Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 269194 (IRSES/ASK). R.A.G. and D. Salabert acknowledge the support of the CNES grant at CEA-Saclay. A.M. acknowledges support from the NIUS programme of HBCSE (TIFR). A.S. is supported by the MICINN grant AYA2011-24704 and by the ESF EUROCORES Program EuroGENESIS (MICINN grant EUI2009-04170). D. Stello is supported by the Australian Research Council.
Published: 2014
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14. Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets

Author: David Barrado, Andrew W. Howard, Daniel Huber, Guillaume Hébrard, Alexandre Santerne, Jon M. Jenkins, David Charbonneau, Tiago L. Campante, Phillip J. MacQueen, Gibor Basri, Guillermo Torres, Fergal Mullally, William J. Borucki, Debra A. Fischer, Roberto Sanchis-Ojeda, Michael R. Haas, Christopher E. Henze, Timothy R. Bedding, Francois Fressin, Timothy R. White, M. Lundkvist, Sarah Ballard, Timothy M. Brown, Jessie L. Christiansen, Dimitar Sasselov, David G. Koch, Andrea K. Dupree, Geoffrey W. Marcy, Hans Kjeldsen, Edna DeVore, Jonathan J. Fortney, Peter Tenenbaum, Jørgen Christensen-Dalsgaard, Howard Isaacson, Susan E. hompson, Dennis Stello, Jill Tarter, Alan P. Boss, Daniel C. Fabrycky, Yvonne Elsworth, David R. Ciardi, Roger C. Hunter, Rasmus Handberg, Joshua N. Winn, Timothy D. Morton, Rea Kolbl, Elisa V. Quintana, Guy R. Davies, Eric Agol, Eric B. Ford, Erik Brugamyer, Christopher J. Burke, Paul Robertson, Mikkel N. Lund, Mark E. Everett, William J. Chaplin, Douglas A. Caldwell, V. Silva Aguirre, Joseph D. Twicken, Justin R. Crepp, Philip W. Lucas, Thomas N. Gautier, Charlie Sobeck, Andrej Prsa, David Morrison, Martin Still, Avi Shporer, Claire Moutou, Michael Endl, Alan Gould, J. A. Carter, Steven D. Kawaler, Thomas Barclay, Jerome A. Orosz, Natalie M. Batalha, Travis S. Metcalfe, David W. Latham, Elisabeth R. Adams, Jason H. Steffen, Sarbani Basu, Jean-Michel Desert, Leslie A. Rogers, Ronald L. Gilliland, Sara Seager, Andrea Miglio, William F. Welsh, Erik A. Petigura, Lauren M. Weiss, Matthew J. Holman, Saskia Hekker, Steve B. Howell, William D. Cochran, Lars A. Buchhave, John Asher Johnson, Jorge Lillo-Box, Christoffer Karoff, Jeffrey L. Coughlin, Douglas Hudgins, Jack J. Lissauer, Stephen T. Bryson, Jeffrey Van Cleve, Samuel N. Quinn, Jason F. Rowe, Sydney Institute for Astronomy (SIfA), The University of Sydney, School of Physics and Astronomy [Birmingham], University of Birmingham [Birmingham], 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), School of Physics and Astronomy, Department of Physics and Astronomy [Aarhus], Aarhus University [Aarhus], Stellar Astrophysics Centre [Aarhus] (SAC), Department of Geoscience [Aarhus], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Department of Chemical Engineering [Hamilton, Ontario], McMaster University [Hamilton, Ontario], Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-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), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Observatoire Astronomique de Marseille Provence (OAMP), Université de Provence - Aix-Marseille 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Space Telescope Science Institute (STSci), Danish AsteroSeismology Centre (DASC), National University of Singapore (NUS), McDonald Observatory, University of Texas at Austin [Austin], Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Las Cumbres Observatory Global Telescope, University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), 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), 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), Universidade do Porto, Smithsonian Institution-Harvard University [Cambridge], University of California [Santa Cruz] (UCSC), University of California, Universidade do Porto [Porto], Harvard University [Cambridge]-Smithsonian Institution, and Low Energy Astrophysics (API, FNWI)
Subjects: Brightness, Doppler spectroscopy, detection [planets and satellites], FOS: Physical sciences, Asteroseismology, photometric [techniques], symbols.namesake, Planet, Astrophysics::Solar and Stellar Astrophysics, planetary systems, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy, Astronomy and Astrophysics, radial velocities [techniques], individual: Kepler-25 Kepler-37 Kepler-48 Kepler-68 Kepler-93 Kepler-94 Kepler-95 Kepler-96 Kepler-97 Kepler-98 Kepler-99 Kepler-100 Kepler-102 Kepler-103 Kepler-106 Kepler-109 Kepler-113 Kepler-131 Kepler-406 Kepler-407 Kepler-409 [stars], Stars, 13. Climate action, Space and Planetary Science, symbols, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Doppler effect, Astrophysics - Earth and Planetary Astrophysics, Kepler-62c
Abstract: We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities for all of the transiting planets (41 of 42 have a false-positive probability under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than 3X the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify 6 planets with densities above 5 g/cc, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than ~2 R_earth. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O)., 94 pages, 55 figures, 25 tables. Accepted by ApJS
Published: 2014
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15. Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants

Author: Jian-Ning Fu, M. J. Goupil, Alex Lobel, S. Deheuvels, Guy R. Davies, J. Molenda-Żakowicz, Othman Benomar, William J. Chaplin, Patrick Eggenberger, Daniel R. Reese, T. Stahn, Tiago L. Campante, Laurent Gizon, G. Doğan, Rafael A. García, Benoit Mosser, Xiao-Hu Yang, Hans Bruntt, Jesper Schou, P. De Cat, Luca Casagrande, T. Ceillier, Jørgen Christensen-Dalsgaard, C. Régulo, Thierry Appourchaux, S. Mathis, A. O. Thygesen, Marc H. Pinsonneault, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Stellar Astrophysics Centre [Aarhus] (SAC), Aarhus University [Aarhus], 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 d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Sydney Institute for Astronomy (SIfA), The University of Sydney, School of Physics and Astronomy [Birmingham], University of Birmingham [Birmingham], Research School of Astronomy and Astrophysics [Canberra] (RSAA), Australian National University (ANU), 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), Royal Observatory of Belgium [Brussels] (ROB), Department of Astronomy, Beijing Normal University, China, Instituto de Astrofisica de Canarias (IAC), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institut für Astrophysik [Göttingen], Georg-August-University [Göttingen], Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Instytut Astronomiczny Uniwersytetu Wrocławskiego, Departments of Astronomy and Chemistry, The Ohio State University, Ohio State University [Columbus] (OSU), 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), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Georg-August-University = Georg-August-Universität Göttingen, Universität Heidelberg [Heidelberg] = Heidelberg University, Université de Genève = University of Geneva (UNIGE), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), 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), and Royal Observatory of Belgium [Brussels]
Subjects: Angular momentum, FOS: Physical sciences, Context (language use), Astrophysics, asteroseismology, Classification of discontinuities, stars: interiors, Rotation, Spectral line, stars: rotation, Astrophysics::Solar and Stellar Astrophysics, stars: evolution, rotation, stars, interiors, evolution, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Envelope (waves), Physics, interiors [stars], Subgiant, Astronomy and Astrophysics, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, evolution [stars], rotation [stars], Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Context : We still do not know which mechanisms are responsible for the transport of angular momentum inside stars. The recent detection of mixed modes that contain the signature of rotation in the spectra of Kepler subgiants and red giants gives us the opportunity to make progress on this issue. Aims: Our aim is to probe the radial dependance of the rotation profiles for a sample of Kepler targets. For this purpose, subgiants and early red giants are particularly interesting targets because their rotational splittings are more sensitive to the rotation outside the deeper core than is the case for their more evolved counterparts. Methods: We first extract the rotational splittings and frequencies of the modes for six young Kepler red giants. We then perform a seismic modeling of these stars using the evolutionary codes CESAM2k and ASTEC. By using the observed splittings and the rotational kernels of the optimal models, we perform inversions of the internal rotation profiles of the six stars. Results: We obtain estimates of the mean rotation rate in the core and in the convective envelope of these stars. We show that the rotation contrast between the core and the envelope increases during the subgiant branch. Our results also suggest that the core of subgiants spins up with time, contrary to the RGB stars whose core has been shown to spin down. For two of the stars, we show that a discontinuous rotation profile with a deep discontinuity reproduces the observed splittings significantly better than a smooth rotation profile. Interestingly, the depths that are found most probable for the discontinuities roughly coincide with the location of the H-burning shell, which separates the layers that contract from those that expand. These results will bring observational constraints to the scenarios of angular momentum transport in stars., Comment: Accepted in A&A, 27 pages, 18 figures
Published: 2014
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16. Convection and Differential Rotation in F-Type Stars

Author: Mark S. Miesch, Allan Sacha Brun, Kyle C. Augustson, Benjamin P. Brown, Juri Toomre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, 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 de Paris (UP), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), 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), 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), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and STARS2
Subjects: Physics, Spherical harmonics, Astronomy and Astrophysics, stars: solar-type, Astrophysics, Type (model theory), stars: interiors, Rotation, Coupling (probability), [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Radiation zone, 010305 fluids & plasmas, Computational physics, Convection zone, Space and Planetary Science, stars: rotation, 0103 physical sciences, hydrodynamics, Differential rotation, 010303 astronomy & astrophysics, Main sequence, convection
Abstract: International audience; Differential rotation is a common feature of main-sequence spectral F-type stars. In seeking to make contact with observations and to provide a self-consistent picture of how differential rotation is achieved in the interiors of these stars, we use the three-dimensional anelastic spherical harmonic (ASH) code to simulate global-scale turbulent flows in 1.2 and 1.3 $M_\odot$ F-type stars at varying rotation rates. The simulations are carried out in spherical shells that encompass most of the convection zone and a portion of the stably stratified radiative zone below it, allowing us to explore the effects of overshooting convection. We examine the scaling of the mean flows and thermal state with rotation rate and mass and link these scalings to fundamental parameters of the simulations. Indeed, we find that the differential rotation becomes much stronger with more rapid rotation and larger mass, scaling as $\Delta\Omega$ $\alpha$ $M^{3.9}$$\Omega_0^{0.6}$. Accompanying the growing differential rotation is a significant latitudinal temperature contrast, with amplitudes of 1000 K or higher in the most rapidly rotating cases. This contrast in turn scales with mass and rotation rate as $\Delta$$T$ $\alpha$ $M^{6.4}$$\Omega_0^{1.6}$. On the other hand, the meridional circulations become much weaker with more rapid rotation and with higher mass, with their kinetic energy decreasing as KE$_{MC}$ $\alpha$ $M^{-1.2}$$\Omega_0^{-0.8}$. Additionally, three of our simulations exhibit a global-scale shear instability within their stable regions that persists for the duration of the simulations. The flow structures associated with the instabilities have a direct coupling to and impact on the flows within the convection zone.
Published: 2013
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17. Solar magnetism eXplorer (SolmeX)

Author: Peter, Hardi, Abbo, L., Andretta, V., Auchère, F., Bemporad, A., Berrilli, F., Bommier, V., Braukhane, A., Casini, R., Curdt, W., Davila, J., Dittus, H., Fineschi, S., Fludra, A., Gandorfer, A., Griffin, D., Inhester, B., Lagg, A., Degl’innocenti, E. Landi, Maiwald, V., Sainz, R. Manso, Pillet, V. Martínez, Matthews, S., Moses, D., Parenti, S., Pietarila, A., Quantius, D., Raouafi, N. -E., Raymond, J., Rochus, P., Romberg, O., Schlotterer, M., Schühle, U., Solanki, S., Spadaro, D., Teriaca, L., Tomczyk, S., Bueno, J. Trujillo, Vial, J. -C., INAF - Osservatorio Astronomico di Capodimonte (OAC), Istituto Nazionale di Astrofisica (INAF), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, NASA Goddard Space Flight Center (GSFC), DLR Institute of Space Systems, German Aerospace Center (DLR), INAF - Osservatorio Astrofisico di Torino (OATo), Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Centre Spatial de Liège (CSL), Université de Liège, Max Planck Institute for Solar System Research (MPS), Università degli Studi di Firenze [Firenze], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Università degli Studi di Firenze = University of Florence (UniFI), and Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS)
Subjects: [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Space Physics (physics.space-ph), Physics - Plasma Physics, Plasma Physics (physics.plasm-ph), Astrophysics - Solar and Stellar Astrophysics, Physics - Space Physics, [SDU]Sciences of the Universe [physics], Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS
Abstract: The magnetic field plays a pivotal role in many fields of Astrophysics. This is especially true for the physics of the solar atmosphere. Measuring the magnetic field in the upper solar atmosphere is crucial to understand the nature of the underlying physical processes that drive the violent dynamics of the solar corona -- that can also affect life on Earth. SolmeX, a fully equipped solar space observatory for remote-sensing observations, will provide the first comprehensive measurements of the strength and direction of the magnetic field in the upper solar atmosphere. The mission consists of two spacecraft, one carrying the instruments, and another one in formation flight at a distance of about 200m carrying the occulter to provide an artificial total solar eclipse. This will ensure high-quality coronagraphic observations above the solar limb. Solmex integrates two spectro-polarimetric coronagraphs for off-limb observations, one in the EUV and one in the IR, and three instruments for observations on the disk. The latter comprises one imaging polarimeter in the EUV for coronal studies, a spectro-polarimeter in the EUV to investigate the low corona, and an imaging spectro-polarimeter in the UV for chromospheric studies. SOHO and other existing missions have investigated the emission of the upper atmosphere in detail (not considering polarization), and as this will be the case also for missions planned for the near future. Therefore it is timely that SolmeX provides the final piece of the observational quest by measuring the magnetic field in the upper atmosphere through polarimetric observations., Submitted to Experimental Astronomy. 30 pages, 19 figures
Published: 2012
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18. Magnetic Braking Formulation for Sun-Like Stars: Dependence on Dipole Field Strength and Rotation Rate

Author: Sean P. Matt, Thomas P. Greene, Marc H. Pinsonneault, K. B. MacGregor, 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Department of Astronomy, Ohio State University [Columbus] (OSU), NASA Ames Research Center (ARC), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), 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: Physics, Angular momentum, FOS: Physical sciences, Astronomy and Astrophysics, Rotation, 01 natural sciences, Computational physics, Magnetic field, Stars, Dipole, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, 010306 general physics, 010303 astronomy & astrophysics, Magnetic dipole, Solar and Stellar Astrophysics (astro-ph.SR), Main sequence
Abstract: We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide range of relative magnetic field strengths and rotation rates, extending from the slow- and approaching the fast-magnetic-rotator regimes. Using the simulations to compute the angular momentum loss, we derive a semi-analytic formulation for the external torque on the star that fits all of the simulations to a precision of a few percents. This formula provides a simple method for computing the magnetic braking of sun-like stars due to magnetized stellar winds, which properly includes the dependence on the strength of the magnetic field, mass loss rate, stellar radius, suface gravity, and spin rate and which is valid for both slow and fast rotators., Accepted for publication in ApJ Letters, 6 pages, 4 figures
Published: 2012
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19. Magnetic Wreaths and Cycles in Convective Dynamos

Author: Mark S. Miesch, Benjamin P. Brown, Allan Sacha Brun, Nicholas J. Nelson, Juri Toomre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR7158 / 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 Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Convection, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, 01 natural sciences, Geomagnetic reversal, Physics::Fluid Dynamics, symbols.namesake, 0103 physical sciences, Differential rotation, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Reynolds number, Astronomy and Astrophysics, Mechanics, Computational Physics (physics.comp-ph), Magnetic flux, Magnetic field, Electromagnetic induction, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, symbols, Physics - Computational Physics, Dynamo
Abstract: Solar-type stars exhibit a rich variety of magnetic activity. Seeking to explore the convective origins of this activity, we have carried out a series of global 3D magnetohydrodynamic (MHD) simulations with the anelastic spherical harmonic (ASH) code. Here we report on the dynamo mechanisms achieved as the effects of artificial diffusion are systematically decreased. The simulations are carried out at a nominal rotation rate of three times the solar value (3$\Omega_\odot$), but similar dynamics may also apply to the Sun. Our previous simulations demonstrated that convective dynamos can build persistent toroidal flux structures (magnetic wreaths) in the midst of a turbulent convection zone and that high rotation rates promote the cyclic reversal of these wreaths. Here we demonstrate that magnetic cycles can also be achieved by reducing the diffusion, thus increasing the Reynolds and magnetic Reynolds numbers. In these more turbulent models, diffusive processes no longer play a significant role in the key dynamical balances that establish and maintain the differential rotation and magnetic wreaths. Magnetic reversals are attributed to an imbalance in the poloidal magnetic induction by convective motions that is stabilized at higher diffusion levels. Additionally, the enhanced levels of turbulence lead to greater intermittency in the toroidal magnetic wreaths, promoting the generation of buoyant magnetic loops that rise from the deep interior to the upper regions of our simulated domain. The implications of such turbulence-induced magnetic buoyancy for solar and stellar flux emergence are also discussed., Comment: 21 pages, 16 figures, accepted for publication in ApJ
Published: 2012
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20. Ensemble asteroseismology of solar-type stars with the NASA Kepler mission

Author: Mário J. P. F. G. Monteiro, Tiago L. Campante, L. Esch, William J. Borucki, M. D. Suran, Dennis Stello, Graham A. Verner, Travis S. Metcalfe, Jon M. Jenkins, Jørgen Christensen-Dalsgaard, Alfio Bonanno, Enrico Corsaro, William J. Chaplin, Andrea Miglio, D. Salabert, Savita Mathur, Orlagh Creevey, J. Van Cleve, Joanna Molenda-Żakowicz, I. M. Brandão, Daniel Huber, Steven J. Hale, Christoffer Karoff, Jérôme Ballot, G. Houdek, D. Pricopi, Aldo Serenelli, Rafael A. García, L. Girardi, Todd C. Klaus, Yvonne Elsworth, H. Bruntt, Patrick Gaulme, S. G. Sousa, Saskia Hekker, A.-M. Broomhall, Timothy R. Bedding, Roger New, P.-O. Quirion, Ian R. Stevens, Ning Gai, T. Appourchaux, Ronald L. Gilliland, V. Silva Aguirre, Michael Thompson, Sarbani Basu, Timothy R. White, S. D. Kawaler, Clara Régulo, Marc H. Pinsonneault, G. Doğan, K. Uytterhoeven, Timothy M. Brown, Anwesh Mazumdar, Hans Kjeldsen, Karen Kinemuchi, Rasmus Handberg, B. Mosser, Antonio Jiménez, School of Physics and Astronomy, University of Birmingham [Birmingham], Aarhus University [Aarhus], Yale University [New Haven], Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Sydney Institute for Astronomy (SIfA), The University of Sydney, 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), Space Telescope Science Institute (STSci), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), University of Vienna [Vienna], Iowa State University (ISU), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), University of Wrocław [Poland] (UWr), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, 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), INAF - Osservatorio Astrofisico di Catania (OACT), Universidad de La Laguna [Tenerife - SP] (ULL), Instituto de Astrofisica de Canarias (IAC), Homi Bhabha National Institute (HBNI), 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), Materials and Engineering Research Institute [Sheffield] (MERI), Sheffield Hallam University, Ohio State University [Columbus] (OSU), Astronomical Institute of Romanian Academy, Romanian Academy, Canadian Space Agency (CSA), Institut d'Estudis Espacials de Catalunya (IEEC-CSIC), Max Planck Institute for Astrophysics, Max-Planck-Gesellschaft, NASA Ames Research Center (ARC), Las Cumbres Observatory (LCO), Low Energy Astrophysics (API, FNWI), Stellar Astrophysics Centre [Aarhus] (SAC), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), 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 de Paris (UP), Universidade do Porto, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Faculdade de Ciências
Subjects: Astronomia, Física, Física [Ciências exactas e naturais], 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Asteroseismology, Kepler Input Catalog, Kepler-47, Physical sciences [Natural sciences], Astronomy, Physical sciences, Stellar dynamics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Kepler-62, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Multidisciplinary, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Stellar collision, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Exoplanet, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Kepler-62c
Abstract: In addition to its search for extra-solar planets, the NASA Kepler Mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solartype stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius and age) and to test theories of stellar evolution. We find that the distribution of observed masses of these stars shows intriguing differences to predictions from models of synthetic stellar populations in the Galaxy., 20 pages, including on-line supporting material
Published: 2011
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21. Magnetic Cycles in a Convective Dynamo Simulation of a Young Solar-type Star

Author: Mark S. Miesch, Matthew K. Browning, Benjamin P. Brown, Allan Sacha Brun, Juri Toomre, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), 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), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR7158 / 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 Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Convection, Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Magnetic field, Physics::Fluid Dynamics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Differential rotation, Polar, Solar rotation, Astrophysics::Solar and Stellar Astrophysics, Magnetohydrodynamics, Solar dynamo, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Dynamo
Abstract: Young solar-type stars rotate rapidly and many are magnetically active; some undergo magnetic cycles similar to the 22-year solar activity cycle. We conduct simulations of dynamo action in rapidly rotating suns with the 3D MHD anelastic spherical harmonic (ASH) code to explore dynamo action achieved in the convective envelope of a solar-type star rotating at 5 times the current solar rotation rate. Striking global-scale magnetic wreaths appear in the midst of the turbulent convection zone and show rich time-dependence. The dynamo exhibits cyclic activity and undergoes quasi-periodic polarity reversals where both the global-scale poloidal and toroidal fields change in sense on a roughly 1500 day time scale. These magnetic activity patterns emerge spontaneously from the turbulent flow and are more organized temporally and spatially than those realized in our previous simulations of the solar dynamo. We assess in detail the competing processes of magnetic field creation and destruction within our simulations that contribute to the global-scale reversals. We find that the mean toroidal fields are built primarily through an $\Omega$-effect, while the mean poloidal fields are built by turbulent correlations which are not necessarily well represented by a simple $\alpha$-effect. During a reversal the magnetic wreaths propagate towards the polar regions, and this appears to arise from a poleward propagating dynamo wave. The primary response in the convective flows involves the axisymmetric differential rotation which shows variations associated with the poleward propagating magnetic wreaths. In the Sun, similar patterns are observed in the poleward branch of the torsional oscillations, and these may represent poleward propagating magnetic fields deep below the solar surface. [abridged], Comment: 20 pages, 14 figures, emulateapj format; accepted for publication in ApJ. Expanded and published version of sections 5-6 from http://arxiv.org/abs/0906.2407
Published: 2011
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22. Modeling the Dynamical Coupling of Solar Convection With the Radiative Interior

Author: Brun, A.S., S. Miesch, Mark, Toomre, Juri, 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], STARS2, European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR7158 / 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 Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics::Fluid Dynamics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics
Abstract: International audience; The global dynamics of a rotating star like the Sun involves the coupling of a highly turbulent convective envelope overlying a seemingly benign radiative interior. We use the anelastic spherical harmonic code to develop a new class of three-dimensional models that nonlinearly couple the convective envelope to a deep stable radiative interior. The numerical simulation assumes a realistic solar stratification from r = 0.07 up to 0.97R (with R the solar radius), thus encompassing part of the nuclear core up through most of the convection zone. We find that a tachocline naturally establishes itself between the differentially rotating convective envelope and the solid body rotation of the interior, with a slow spreading that is here diffusively controlled. The rapid angular momentum redistribution in the convective envelope leads to a fast equator and slow poles, with a conical differential rotation achieved at mid-latitudes, much as has been deduced by helioseismology. The convective motions are able to overshoot downward about 0.04R into the radiative interior. However, the convective meridional circulation there is confined to a smaller penetration depth and is directed mostly equatorward at the base of the convection zone. Thermal wind balance is established in the lower convection zone and tachocline but departures are evident in the upper convection zone. Internal gravity waves are excited by the convective overshooting, yielding a complex wave field throughout the radiative interior.
Published: 2011
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23. Buoyant Magnetic Loops in a Global Dynamo Simulation of a Young Sun

Author: Nicholas J. Nelson, Mark S. Miesch, Juri Toomre, Benjamin P. Brown, Allan Sacha Brun, Joint Institute for Laboratory Astrophysics (JILA), National Institute of Standards and Technology [Gaithersburg] (NIST)-University of Colorado [Boulder], Department of Astronomy [Madison], University of Wisconsin-Madison, 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), European Project: 207430,EC:FP7:ERC,ERC-2007-StG,STARS2(2008), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), 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: Convection, FOS: Physical sciences, 01 natural sciences, Physics::Fluid Dynamics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, magnetic field -Sun, Photosphere, Sunspot, activity, Starspot, Stellar atmosphere, Astronomy and Astrophysics, Mechanics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics - Plasma Physics, Plasma Physics (physics.plasm-ph), convection -magnetohydrodynamics (MHD) -stars, Convection zone, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, interiors -stars, Magnetohydrodynamics, Dynamo
Abstract: The current dynamo paradigm for the Sun and sun-like stars places the generation site for strong toroidal magnetic structures deep in the solar interior. Sunspots and star-spots on sun-like stars are believed to arise when sections of these magnetic structures become buoyantly unstable and rise from the deep interior to the photosphere. Here we present the first 3-D global magnetohydrodynamic (MHD) simulation in which turbulent convection, stratification, and rotation combine to yield a dynamo that self-consistently generates buoyant magnetic loops. We simulate stellar convection and dynamo action in a spherical shell with solar stratification, but rotating three times faster than the current solar rate. Strong wreaths of toroidal magnetic field are realized by dynamo action in the convection zone. By turning to a dynamic Smagorinsky model for subgrid-scale turbulence, we here attain considerably reduced diffusion in our simulation. This permits the regions of strongest magnetic field in these wreaths to rise toward the top of the convection zone via a combination of magnetic buoyancy instabilities and advection by convective giant cells. Such a global simulation yielding buoyant loops represents a significant step forward in combining numerical models of dynamo action and flux emergence., 6 pages, 3 figures, accepted in ApJ Letters
Published: 2011
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24. Simulation of electric field and current during the 11 June 1993 disturbance dynamo event: Comparison with the observations

Author: Zaka, K.Z., Kobea, A. T., Doumbia, V., Richmond, A.D., Maute, A., Mene, N.M., Obrou, O.K., Assamoi, P., Boka, K., Adohi, J.P., Amory-Mazaudier, Christine, Laboratoire de Physique de l'Atmosphère, Université de Cocody, 22 BP 582 Abidjan 22, High Altitude Observatory (HAO), and National Center for Atmospheric Research [Boulder] (NCAR)
Subjects: [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDE.MCG]Environmental Sciences/Global Changes, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Physics::Atmospheric and Oceanic Physics, Physics::Geophysics
Abstract: International audience; The ionospheric disturbance dynamo signature in geomagnetic variations is investigated using the National Center for Atmospheric Research Thermosphere‐ Ionosphere‐Electrodynamics General Circulation Model. The model results are tested against reference magnetically quiet time observations on 21 June 1993, and disturbance effects were observed on 11 June 1993. The model qualitatively reproduces the observed diurnal and latitude variations of the geomagnetic horizontal intensity and declination for the reference quiet day in midlatitude and low‐latitude regions but underestimates their amplitudes. The patterns of the disturbance dynamo signature and its source "anti‐Sq" current system are well reproduced in the Northern Hemisphere. However, the model significantly underestimates the amplitude of disturbance dynamo effects when compared with observations. Furthermore, the largest simulated disturbances occur at different local times than the observations. The discrepancies suggest that the assumed high‐latitude storm time energy inputs in the model were not quantitatively accurate for this storm.
Published: 2010
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25. CoRoT reveals a magnetic activity cycle in a Sun-like star

Author: Savita Mathur, Clara Régulo, Rafael A. García, D. Salabert, Travis S. Metcalfe, A. Baglin, Jérôme Ballot, 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Instituto de Astrofisica de Canarias (IAC), 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), 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), 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), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, 0103 physical sciences, Modulation (music), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, 010308 nuclear & particles physics, Oscillation, Stellar rotation, Mode (statistics), Astronomy, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Amplitude, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Physics::Space Physics, Activity cycle, Astrophysics::Earth and Planetary Astrophysics, Dynamo, Astrophysics - Earth and Planetary Astrophysics
Abstract: The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT space mission, showing solar-like oscillations in the star HD49933, for signatures of stellar magnetic activity. Asteroseismic measurements of global changes in the oscillation frequencies and mode amplitudes reveal a modulation of at least 120 days, with the minimum frequency shift corresponding to maximum amplitude as in the Sun. These observations are evidence of a stellar magnetic activity cycle taking place beneath the surface of HD49933 and provide constraints for stellar dynamo models under conditions different from those of the Sun., Comment: Brevia text and supporting online material, published in Science
Published: 2010
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26. The Asteroseismic Potential of Kepler: First Results for Solar-Type Stars

Author: W. J. Chaplin, T. Appourchaux, Y. Elsworth, R. A. García, G. Houdek, C. Karoff, T. S. Metcalfe, J. Molenda-Żakowicz, M. J. P. F. G. Monteiro, M. J. Thompson, T. M. Brown, J. Christensen-Dalsgaard, R. L. Gilliland, H. Kjeldsen, W. J. Borucki, D. Koch, J. M. Jenkins, J. Ballot, S. Basu, M. Bazot, T. R. Bedding, O. Benomar, A. Bonanno, I. M. Brandão, H. Bruntt, T. L. Campante, O. L. Creevey, M. P. Di Mauro, G. Doğan, S. Dreizler, P. Eggenberger, L. Esch, S. T. Fletcher, S. Frandsen, N. Gai, P. Gaulme, R. Handberg, S. Hekker, R. Howe, D. Huber, S. G. Korzennik, J. C. Lebrun, S. Leccia, M. Martic, S. Mathur, B. Mosser, R. New, P.-O. Quirion, C. Régulo, I. W. Roxburgh, D. Salabert, J. Schou, S. G. Sousa, D. Stello, G. A. Verner, T. Arentoft, C. Barban, K. Belkacem, S. Benatti, K. Biazzo, P. Boumier, P. A. Bradley, A.-M. Broomhall, D. L. Buzasi, R. U. Claudi, M. S. Cunha, F. D'Antona, S. Deheuvels, A. Derekas, A. García Hernández, M. S. Giampapa, M. J. Goupil, M. Gruberbauer, J. A. Guzik, S. J. Hale, M. J. Ireland, L. L. Kiss, I. N. Kitiashvili, K. Kolenberg, H. Korhonen, A. G. Kosovichev, F. Kupka, Y. Lebreton, B. Leroy, H.-G. Ludwig, S. Mathis, E. Michel, A. Miglio, J. Montalbán, A. Moya, A. Noels, R. W. Noyes, P. L. Pallé, L. Piau, H. L. Preston, T. Roca Cortés, M. Roth, K. H. Sato, J. Schmitt, A. M. Serenelli, V. Silva Aguirre, I. R. Stevens, J. C. Suárez, M. D. Suran, R. Trampedach, S. Turck-Chièze, K. Uytterhoeven, R. Ventura, P. A. Wilson, School of Physics and Astronomy [Birmingham], University of Birmingham [Birmingham], Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Institute for Astronomy [Vienna], University of Vienna [Vienna], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Astronomical Institute [Wroclaw], University of Wrocław [Poland] (UWr), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, School of Mathematics and Statistics [Sheffield] (SoMaS), University of Sheffield [Sheffield], Las Cumbres Observatory (LCO), Department of Physics and Astronomy [Aarhus], Aarhus University [Aarhus], Space Telescope Science Institute (STSci), NASA Ames Research Center (ARC), SETI Institute, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Department of Astronomy [New Haven], Yale University [New Haven], Sydney Institute for Astronomy (SIfA), The University of Sydney, INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), Observatoire de Paris, Université Paris sciences et lettres (PSL), Departamento de Astrofísica [La laguna], Universidad de La Laguna [Tenerife - SP] (ULL), Instituto de Astrofisica de Canarias (IAC), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Institut für Astrophysik [Göttingen], Georg-August-University [Göttingen], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Materials and Engineering Research Institute [Sheffield] (MERI), Sheffield Hallam University, Beijing Normal University (BNU), National Solar Observatory [Tucson] (NSO/Tucson), National Science Foundation [Arlington] (NSF)-Association of Universities for Research in Astronomy (AURA), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (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)-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), INAF - Osservatorio Astronomico di Capodimonte (OAC), Indian Institute of Astrophysics (IIA), Observatoire de Paris - Site de Paris (OP), 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 (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Canadian Space Agency (CSA), Astronomy Unit [London] (AU), Queen Mary University of London (QMUL), Hansen Experimental Physics Lab [Stanford] (HEPL), Stanford University, Département d'astrophysique, Géophysique et Océanographie (AGO), Université de Liège, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, INAF - Osservatorio Astrofisico di Arcetri (OAA), Los Alamos National Laboratory (LANL), Eureka Scientific, INAF - Osservatorio Astronomico di Padova (OAPD), INAF - Osservatorio Astronomico di Roma (OAR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Astronomy and Physics [Halifax], Saint Mary's University [Halifax], Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut d'Astrophysique et de Géophysique [Liège], Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Universidade do Porto = University of Porto, 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), Georg-August-University = Georg-August-Universität Göttingen, Université de Genève = University of Geneva (UNIGE), Harvard University-Smithsonian Institution, 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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), Università degli Studi di Padova = University of Padua (Unipd), and Faculdade de Ciências
Subjects: oscillations [stars], Física [Ciências exactas e naturais], FOS: Physical sciences, Astrophysics, Type (model theory), Star (graph theory), stars: interiors, 01 natural sciences, Kepler, Spectral line, Physical sciences [Natural sciences], Astrophysics, Astronomy, Physical sciences, Physical sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrofísica, Astronomia, Ciências Físicas, Física, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, interiors [stars], 010308 nuclear & particles physics, Oscillation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], stars: late-type, Astronomy and Astrophysics, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, late-type [stars], Astrophysics::Earth and Planetary Astrophysics, stars: oscillations
Abstract: We present preliminary asteroseismic results from Kepler on three G-type stars. The observations, made at one-minute cadence during the first 33.5d of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: About 20 modes of oscillation may be clearly distinguished in each star. We discuss the appearance of the oscillation spectra, use the frequencies and frequency separations to provide first results on the radii, masses and ages of the stars, and comment in the light of these results on prospects for inference on other solar-type stars that Kepler will observe., Comment: 16 pages, 3 figures, 1 table; now accepted for publication in ApJ Letters
Published: 2010
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27. Seasonal oscillations of middle atmosphere temperature observed by Rayleigh lidars and their comparisons with TIMED/SABER observations

Author: Jiyao Xu, Thierry Leblanc, M. G. Mlynczak, Craig Heinselman, Hassan Bencherif, Hanli Liu, Alain Hauchecorne, James M. Russell, Xianghui Xue, Philippe Keckhut, Xiankang Dou, I. Stuart McDermid, Shui Wang, Wolfgang Steinbrecht, Tao Li, School of Earth and Space Sciences [Hefei], University of Science and Technology of China [Hefei] (USTC), Mengcheng National Geophysical Observatory (MENGO), State Key Laboratory for Space Weather [Beijing] (SKSW), National Space Science Center [Beijing] (NSSC), Chinese Academy of Sciences [Beijing] (CAS)-Chinese Academy of Sciences [Beijing] (CAS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-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 de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'Atmosphère et des Cyclones (LACy), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Météo France, SRI International [Menlo Park] (SRI), Meteorologisches Observatorium Hohenpeißenberg (MOHp), Deutscher Wetterdienst [Offenbach] (DWD), NASA Langley Research Center [Hampton] (LaRC), Center for Atmospheric Sciences [Hampton] (CAS), Hampton University, European Commission, State Key Laboratory of Space Weather [Beijing] (SKSW), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Météo-France
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Soil Science, Aquatic Science, Oceanography, 01 natural sciences, Mesosphere, Atmosphere, Geochemistry and Petrology, Observatory, 0103 physical sciences, Rayleigh lidar, Earth and Planetary Sciences (miscellaneous), 010303 astronomy & astrophysics, Stratosphere, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Seasonal oscillation, Ecology, Paleontology, Forestry, Atmospheric temperature, Depth sounding, Geophysics, Lidar, 13. Climate action, Space and Planetary Science, Climatology, Middle atmosphere temperature, Environmental science, Thermosphere
Abstract: International audience; The long-term temperature data sets obtained by Rayleigh lidars at six different locations from low to high latitudes within the Network for the Detection of Atmospheric Composition Change (NDACC) were used to derive the annual oscillations (AO) and semiannual oscillations (SAO) of middle atmosphere temperature: Reunion Island (21.8°S); Mauna Loa Observatory, Hawaii (19.5°N); Table Mountain Facility, California (34.4°N); Observatoire de Haute Provence, France (43.9°N); Hohenpeissenberg, Germany (47.8°N); Sondre Stromfjord, Greenland (67.0°N). The results were compared with those derived from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite
Published: 2009
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28. The correlation of longitudinal/seasonal variations of evening equatorial pre-reversal drift and of plasma bubbles

Author: G. Li, B. Ning, L. Liu, Z. Ren, J. Lei, S.-Y. Su, Institute of Geology and Geophysics [Beijing] (IGG), Chinese Academy of Sciences [Beijing] (CAS), Wuhan Institute of Physics and Mathematics, Graduate School of the Chinese Academy of Sciences (GSCAS), Chinese Academy of Sciences [Changchun Branch] (CAS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), and EGU, Publication
Subjects: Atmospheric Science, Evening, Drift velocity, Magnetic dip, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Atmospheric sciences, F region, Earth and Planetary Sciences (miscellaneous), Solstice, lcsh:Science, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, Solar maximum, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Space and Planetary Science, Physics::Space Physics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, Ionosphere, Longitude, lcsh:Physics
Abstract: The evening pre-reversal vertical drift velocity enhancement (PRE) constitutes an important seeding mechanism for the generation of F region irregularities. Ion density and drift measurements from ROCSAT-1 and DMSP satellites are used to examine the correlation of longitudinal/seasonal (l/s) variations in the evening pre-reversal vertical drift velocity at the magnetic equator in the topside ionosphere and the plasma bubble (PB) occurrence probability. The analysis performed for three years 2000–2002 (solar maximum), provides consistent evidence as the ground observations that the equatorial PB occurrence is dependent on and increases approximately linearly with PRE, and the l/s variations of PRE play an important role in the global l/s distribution of PB occurrence. The solstitial evening PRE and equatorial PB occurrence show similar longitudinal variations: During June solstice, two peaks appear in the African and Pacific longitude sectors, and two minimums are observed in the Indian and American regions; During December solstice, the situation is approximately opposite. The equinoctial longitudinal effects are comparably small. It is concluded that the large-scale l/s variations of equatorial PB occurrence can be closely related to the l/s variations of PRE.
Published: 2008

29. A multisite campaign to measure solar-like oscillations in Procyon. I. Observations, data reduction, and slow variations

Author: François Bouchy, Jerome Schmitt, Fabien Carrier, Thierry Appourchaux, M. Martic, Riccardo Claudi, Michael Bazot, Serena Benatti, Benoit Mosser, Danuta Sosnowska, Jean-Loup Bertaux, L. Glowienka, Hans Bruntt, Caroline Barban, Simon J. O'Toole, Timothy R. Bedding, Rafael A. García, Artie P. Hatzes, Karsten Brogaard, Eiji Kambe, Michael Endl, Silvio Leccia, Patrick Eggenberger, Janine Provost, Hans Kjeldsen, S. Frandsen, Torben Arentoft, Sylvaine Turck-Chièze, Eric Stempels, Travis S. Metcalfe, László L. Kiss, T. H. Dall, Bun'ei Sato, Hideyuki Izumiura, Gabrielle Berthomieu, R. Paul Butler, M. Hartmann, Eric Michel, Joergen Christensen-Dalsgaard, Frank Grundahl, Sabine Reffert, Rosario Cosentino, Saskia Hekker, Hiroyasu Ando, Alfio Bonanno, Christoffer Karoff, Robert A. Wittenmyer, J. C. Lebrun, Danish AsteroSeismology Centre (DASC), Aarhus University [Aarhus], Sydney Institute for Astronomy (SIfA), The University of Sydney, Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Gemini Observatory [Southern Operations Center], Association of Universities for Research in Astronomy (AURA), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), EPFL Laboratoire d’astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), McDonald Observatory, University of Texas at Austin [Austin], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Leiden Observatory [Leiden], Universiteit Leiden, Royal Observatory of Belgium [Brussels] (ROB), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg] = Heidelberg University, Department of Terrestrial Magnetism [Carnegie Institution], Carnegie Institution for Science, Anglo-Australian Observatory (AAO), Okayama Astrophysical Observatory (OAO), National Astronomical Observatory of Japan (NAOJ), Global Edge Institute, Tokyo Institute of Technology [Tokyo] (TITECH), Thüringer Landessternwarte Tautenburg (TLS), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Paris (OP), 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, 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 d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), 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), 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), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Padova (OAPD), INAF - Osservatorio Astronomico di Capodimonte (OAC), SUPA School of Physics and Astronomy [University of St Andrews], University of St Andrews [Scotland]-Scottish Universities Physics Alliance (SUPA), Universidade do Porto, Université de Genève (UNIGE), Universiteit Leiden [Leiden], Universität Heidelberg [Heidelberg], Carnegie Institution for Science [Washington], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), and 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)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Stellar rotation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Radial velocity, Stars, Amplitude, Space and Planetary Science, 0103 physical sciences, Modulation (music), Astrophysics::Solar and Stellar Astrophysics, Solar-like oscillations, Astrophysics::Earth and Planetary Astrophysics, Variation (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Data reduction
Abstract: We have carried out a multi-site campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with eleven telescopes, with almost continuous coverage for the central ten days. This represents the most extensive campaign so far organized on any solar-type oscillator. We describe in detail the methods we used for processing and combining the data. These involved calculating weights for the velocity time series from the measurement uncertainties and adjusting them in order to minimize the noise level of the combined data. The time series of velocities for Procyon shows the clear signature of oscillations, with a plateau of excess power that is centred at 0.9 mHz and is broader than has been seen for other stars. The mean amplitude of the radial modes is 38.1 +/- 1.3 cm/s (2.0 times solar), which is consistent with previous detections from the ground and by the WIRE spacecraft, and also with the upper limit set by the MOST spacecraft. The variation of the amplitude during the observing campaign allows us to estimate the mode lifetime to be 1.5 d (+1.9/-0.8 d). We also find a slow variation in the radial velocity of Procyon, with good agreement between different telescopes. These variations are remarkably similar to those seen in the Sun, and we interpret them as being due to rotational modulation from active regions on the stellar surface. The variations appear to have a period of about 10 days, which presumably equals the stellar rotation period or, perhaps, half of it. The amount of power in these slow variations indicates that the fractional area of Procyon covered by active regions is slightly higher than for the Sun., accepted for publication in ApJ. Minor change to Fig 11
Published: 2008
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30. Assessment of ionospheric Joule heating by GUMICS-4 MHD simulation, AMIE, and satellite-based statistics: towards a synthesis

Author: M. Palmroth, P. Janhunen, T. I. Pulkkinen, A. Aksnes, G. Lu, N. Østgaard, J. Watermann, G. D. Reeves, G. A. Germany, Finnish Meteorological Institute (FMI), University of Bergen (UiB), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Danish Meteorological Institute (DMI), Los Alamos National Laboratory (LANL), Center for Space Plasma and Aeronomic Research [Huntsville] (CSPAR), University of Alabama in Huntsville (UAH), and EGU, Publication
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, 0103 physical sciences, Substorm, Earth and Planetary Sciences (miscellaneous), Magnetohydrodynamic drive, lcsh:Science, 0105 earth and related environmental sciences, Physics, Geomagnetic storm, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Solar wind, 13. Climate action, Space and Planetary Science, Physics::Space Physics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, Ionosphere, Magnetohydrodynamics, Joule heating, lcsh:Physics
Abstract: We investigate the Northern Hemisphere Joule heating from several observational and computational sources with the purpose of calibrating a previously identified functional dependence between solar wind parameters and ionospheric total energy consumption computed from a global magnetohydrodynamic (MHD) simulation (Grand Unified Magnetosphere Ionosphere Coupling Simulation, GUMICS-4). In this paper, the calibration focuses on determining the amount and temporal characteristics of Northern Hemisphere Joule heating. Joule heating during a substorm is estimated from global observations, including electric fields provided by Super Dual Auroral Network (SuperDARN) and Pedersen conductances given by the ultraviolet (UV) and X-ray imagers on board the Polar satellite. Furthermore, Joule heating is assessed from several activity index proxies, large statistical surveys, assimilative data methods (AMIE), and the global MHD simulation GUMICS-4. We show that the temporal and spatial variation of the Joule heating computed from the GUMICS-4 simulation is consistent with observational and statistical methods. However, the different observational methods do not give a consistent estimate for the magnitude of the global Joule heating. We suggest that multiplying the GUMICS-4 total Joule heating by a factor of 10 approximates the observed Joule heating reasonably well. The lesser amount of Joule heating in GUMICS-4 is essentially caused by weaker Region 2 currents and polar cap potentials. We also show by theoretical arguments that multiplying independent measurements of averaged electric fields and Pedersen conductances yields an overestimation of Joule heating. Keywords. Ionosphere (Auroral ionosphere; Modeling and forecasting; Electric fields and currents)
Published: 2005

31. IRIS ++ database: Merging of IRIS + Mark-1 + LOWL

Author: M. Lazrek, Eric Fossat, François-Xavier Schmider, S. J. Jiménez-Reyes, J. T. Hoeksema, S. Kholikov, Steven Tomczyk, Sh. A. Ehgamberdiev, A. Cacciani, Pere L. Palle, G. Grec, D. Salabert, Thierry Corbard, B. Gelly, 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), Télescope héliographique pour l'étude du magnétisme et des instabilites solaires (THEMIS), Centre National de la Recherche Scientifique (CNRS), National Solar Observatory [Tucson] (NSO/Tucson), National Science Foundation [Arlington] (NSF)-Association of Universities for Research in Astronomy (AURA), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), and Université Cadi Ayyad [Marrakech] (UCA)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Real-time computing, Network data, Astronomy and Astrophysics, Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Space and Planetary Science, Duty cycle, 0103 physical sciences, 010303 astronomy & astrophysics, Merge (version control), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing
Abstract: The IRIS network has been operated continuously since July 1st 1989. To date, it has acquired more than a complete solar cycle of full-disk helioseismic data which has been used to constrain the structure and rotation of the deep solar interior. However, the duty cycle of the network data has never reached initial expectations. To improve this situation, several cooperations have been developed with teams collecting observations with similar instruments. This paper demonstrates that we are able to merge data from these different instruments in a consistent manner resulting in a very significant improvement in network duty cycle over more than one solar cycle initiating what we call the IRIS + + network.
Published: 2002
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32. Analysis of the solar cycle and core rotation using 15 years of Mark-I observations: 1984-1999

Author: Jiménez-Reyes, S., Corbard, T., Pallé, P., Roca Cortes, T., Tomczyk, S., High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Departamento de Astrofísica [La laguna], and Universidad de La Laguna [Tenerife - SP] (ULL)
Subjects: [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2001
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33. Coordinated Cluster and ground-based instrument observations of transient changes in the magnetopause boundary layer during an interval of predominantly northward IMF: relation to reconnection pulses and FTE signatures

Author: M. Lockwood, A. Fazakerley, H. Opgenoorth, J. Moen, A. P. van Eyken, M. Dunlop, J.-M. Bosqued, G. Lu, C. Cully, P. Eglitis, I. W. McCrea, M. A. Hapgood, M. N. Wild, R. Stamper, W. Denig, M. Taylor, J. A. Wild, G. Provan, O. Amm, K. Kauristie, T. Pulkkinen, A. Strømme, P. Prikryl, F. Pitout, A. Balogh, H. Rème, R. Behlke, T. Hansen, R. Greenwald, H. Frey, S. K. Morley, D. Alcaydé, P.-L. Blelly, E. Donovan, M. Engebretson, M. Lester, J. Watermann, M. F. Marcucci, Solar Terrestrial Physics Division, Department of Space Science and Technology, School of Physics and Astronomy [Southampton], University of Southampton, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), IRF, Department of Physics [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), EISCAT Scientific Association, Blackett Laboratory, Imperial College London, Centre d'étude spatiale des rayonnements (CESR), 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), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), University of Calgary, AFRL Hanscom Research Base (AFB), Air Force Research Laboratory (AFRL), United States Air Force (USAF)-United States Air Force (USAF), Department of Physics and Astonomy, Finnish Meteorological Institute (FMI), University of Tromsø (UiT), Communications Research Centre Canada (CRC), Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Space Science Centre, Department of Physics [Minneapolis], Augsburg College, Danish Meteorological Institute (DMI), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and Consiglio Nazionale delle Ricerche (CNR)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Field line, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Noon, 01 natural sciences, Magnetosheath, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Boundary layer, Space and Planetary Science, Physics::Space Physics, Flux transfer event, Magnetopause, lcsh:Q, lcsh:Physics
Abstract: We study a series of transient entries into the low-latitude boundary layer (LLBL) of all four Cluster spacecraft during an outbound pass through the mid-afternoon magnetopause ( [ XGSM, YGSM, ZGSM ] ≈ [ 2, 7, 9 ] RE). The events take place during an interval of northward IMF, as seen in the data from the ACE satellite and lagged by a propagation delay of 75 min that is welldefined by two separate studies: (1) the magnetospheric variations prior to the northward turning (Lockwood et al., 2001, this issue) and (2) the field clock angle seen by Cluster after it had emerged into the magnetosheath (Opgenoorth et al., 2001, this issue). With an additional lag of 16.5 min, the transient LLBL events correlate well with swings of the IMF clock angle (in GSM) to near 90°. Most of this additional lag is explained by ground-based observations, which reveal signatures of transient reconnection in the pre-noon sector that then take 10–15 min to propagate eastward to 15 MLT, where they are observed by Cluster. The eastward phase speed of these signatures agrees very well with the motion deduced by the cross-correlation of the signatures seen on the four Cluster spacecraft. The evidence that these events are reconnection pulses includes: transient erosion of the noon 630 nm (cusp/cleft) aurora to lower latitudes; transient and travelling enhancements of the flow into the polar cap, imaged by the AMIE technique; and poleward-moving events moving into the polar cap, seen by the EISCAT Svalbard Radar (ESR). A pass of the DMSP-F15 satellite reveals that the open field lines near noon have been opened for some time: the more recently opened field lines were found closer to dusk where the flow transient and the poleward-moving event intersected the satellite pass. The events at Cluster have ion and electron characteristics predicted and observed by Lockwood and Hapgood (1998) for a Flux Transfer Event (FTE), with allowance for magnetospheric ion reflection at Alfvénic disturbances in the magnetopause reconnection layer. Like FTEs, the events are about 1 RE in their direction of motion and show a rise in the magnetic field strength, but unlike FTEs, in general, they show no pressure excess in their core and hence, no characteristic bipolar signature in the boundary-normal component. However, most of the events were observed when the magnetic field was southward, i.e. on the edge of the interior magnetic cusp, or when the field was parallel to the magnetic equatorial plane. Only when the satellite begins to emerge from the exterior boundary (when the field was northward), do the events start to show a pressure excess in their core and the consequent bipolar signature. We identify the events as the first observations of FTEs at middle altitudes.Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; magnetosphere-ionosphere interactions; solar wind-magnetosphere interactions)
Published: 2001

34. Coordinated Cluster, ground-based instrumentation and low-altitude satellite observations of transient poleward-moving events in the ionosphere and in the tail lobe

Author: M. Lockwood, H. Opgenoorth, A. P. van Eyken, A. Fazakerley, J.-M. Bosqued, W. Denig, J. A. Wild, C. Cully, R. Greenwald, G. Lu, O. Amm, H. Frey, A. Strømme, P. Prikryl, M. A. Hapgood, M. N. Wild, R. Stamper, M. Taylor, I. McCrea, K. Kauristie, T. Pulkkinen, F. Pitout, A. Balogh, M. Dunlop, H. Rème, R. Behlke, T. Hansen, G. Provan, P. Eglitis, S. K. Morley, D. Alcaydé, P.-L. Blelly, J. Moen, E. Donovan, M. Engebretson, M. Lester, J. Watermann, M. F. Marcucci, Solar Terrestrial Physics Division [Didcot], Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC)-STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), School of Physics and Astronomy [Southampton], University of Southampton, IRF, EISCAT Scientific Association, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Centre d'étude spatiale des rayonnements (CESR), 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), AFRL Space Vehicles Directorate, Air Force Research Laboratory (AFRL), United States Air Force (USAF)-United States Air Force (USAF), Department of Physics and Astronomy [Leicester], University of Leicester, University of Calgary, Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Finnish Meteorological Institute (FMI), University of California, University of California (UC), University of Tromsø (UiT), Communications Research Centre Canada (CRC), Blackett Laboratory, Imperial College London, Department of Physics [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Department of Physics [Minneapolis], Augsburg College, Danish Meteorological Institute (DMI), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and Consiglio Nazionale delle Ricerche (CNR)
Subjects: Convection, Atmospheric Science, 010504 meteorology & atmospheric sciences, Magnetosphere, Electron precipitation, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, Magnetosheath, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, Solar wind, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Magnetopause, lcsh:Q, Ionosphere, lcsh:Physics
Abstract: During the interval between 8:00–9:30 on 14 January 2001, the four Cluster spacecraft were moving from the central magnetospheric lobe, through the dusk sector mantle, on their way towards intersecting the magnetopause near 15:00 MLT and 15:00 UT. Throughout this interval, the EISCAT Svalbard Radar (ESR) at Longyearbyen observed a series of poleward-moving transient events of enhanced F-region plasma concentration ("polar cap patches"), with a repetition period of the order of 10 min. Allowing for the estimated solar wind propagation delay of 75 ( ± 5) min, the interplanetary magnetic field (IMF) had a southward component during most of the interval. The magnetic footprint of the Cluster spacecraft, mapped to the ionosphere using the Tsyganenko T96 model (with input conditions prevailing during this event), was to the east of the ESR beams. Around 09:05 UT, the DMSP-F12 satellite flew over the ESR and showed a sawtooth cusp ion dispersion signature that also extended into the electrons on the equatorward edge of the cusp, revealing a pulsed magnetopause reconnection. The consequent enhanced ionospheric flow events were imaged by the SuperDARN HF backscatter radars. The average convection patterns (derived using the AMIE technique on data from the magnetometers, the EISCAT and SuperDARN radars, and the DMSP satellites) show that the associated poleward-moving events also convected over the predicted footprint of the Cluster spacecraft. Cluster observed enhancements in the fluxes of both electrons and ions. These events were found to be essentially identical at all four spacecraft, indicating that they had a much larger spatial scale than the satellite separation of the order of 600 km. Some of the events show a correspondence between the lowest energy magnetosheath electrons detected by the PEACE instrument on Cluster (10–20 eV) and the topside ionospheric enhancements seen by the ESR (at 400–700 km). We suggest that a potential barrier at the magnetopause, which prevents the lowest energy electrons from entering the magnetosphere, is reduced when and where the boundary-normal magnetic field is enhanced and that the observed polar cap patches are produced by the consequent enhanced precipitation of the lowest energy electrons, making them and the low energy electron precipitation fossil remnants of the magnetopause reconnection rate pulses.Key words. Magnetospheric physics (polar cap phenomena; solar wind – magnetosphere interactions; magnetosphere – ionosphere interactions)
Published: 2001

35. Electrodynamic coupling of high and low latitudes' Observations on May 27, 1993

Author: C. Peymirat, Arthur D. Richmond, Marc R. Hairston, Christine Amory-Mazaudier, Barbara A. Emery, Therese Moretto, H. Lühr, A. T. Kobea, Laboratoire de Physique de l'Atmosphère, Université de Cocody, 22 BP 582 Abidjan 22, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), Danish Space Research Institute (DSRI), William B. Hanson Center for Space Sciences, University of Texas at Dallas [Richardson] (UT Dallas), Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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: Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Equator, Soil Science, Magnetic dip, Aquatic Science, Noon, Oceanography, Atmospheric sciences, 01 natural sciences, Latitude, Physics::Geophysics, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Geomagnetic storm, Ecology, Paleontology, Forestry, Equatorial electrojet, Geophysics, Earth's magnetic field, 13. Climate action, Space and Planetary Science, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Middle latitudes, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Geology
Abstract: International audience; The penetration of disturbance electric fields from the polar region to the magnetic equator on the dayside of the Earth is examined with geomagnetic data on May 27, 1993. First, we examine a dayside equatorial disturbance that followed the rapid recovery of magnetic activity from a storm and that has the characteristics of overshielding caused by persistent region-2 field-aligned currents. It lasted *0 3 hours. Second, we analyze a series of fluctuations with periods of 25-75 min, to determine the variations of amplitude and phase with magnetic latitude and magnetic local time. The fluctuations were highly coherent at all latitudes between the magnetic equator and the auroral zone, but the coherency decreasedin the polar cap. A northward fluctuation at the equator during midday hours accompanied auroral zone fluctuations that were southward before noon, eastward around noon, and northward after noon. The amplitudes decreased away from the auroral zone toward midlatitudes but were amplified under the equatorial electrojet. No detectablep hased ifferencesa re found, indicating that any temporal lags which might be inducedb y persistencein the region-2f ield-alignedc urrentsa re less than i min for fluctuations having periods like those examined here. A synoptic inversion analysis of the high-latitude magnetic data to estimate the time-varying high-latitude electric potential patterns shows that fluctuations of the high-latitude east-west potential gradient tended to be concentrated around midday, where they were in phase with fluctuations in the midday east-west potential gradient at the magnetic equator.
Published: 2000

36. The Solar Cycle and the Tachocline: Theories and Observations

Author: Corbard, T., Jimenez-Reyes, S.J., Tomoczyk, S., Dikpati, M., Gilman, P., High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), and Corbard, Thierry
Subjects: [PHYS.ASTR.SR] Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Not Available
Published: 2000

37. Structure of the solar core: Effect of asymmetry of peak profiles

Author: S. Basu, S. Turck‐Chieze, G. Berthomieu, A. S. Brun, T. Corbard, G. Gonczi, J. Christensen‐Dalsgaard, J. Provost, S. Thiery, A. H. Gabriel, P. Boumier, United States Nuclear Regulatory Commission (U.S.NRC), Laboratoire Giovanni Domenico Cassini, 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)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Laboratoire Hippolyte Fizeau (FIZEAU), 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), Centre d'études techniques de l'équipement Est (CETE Est), Avant création Cerema, Institut d'astrophysique spatiale (IAS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, media_common.quotation_subject, FOS: Physical sciences, Astrophysics, 01 natural sciences, Asymmetry, Spectral line, Solar core, Speed of sound, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, media_common, Physics, Spacecraft, business.industry, Oscillation, Astrophysics (astro-ph), Astronomy and Astrophysics, Inversion (meteorology), [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Computational physics, On board, Space and Planetary Science, Physics::Space Physics, business
Abstract: Recent studies have established that peaks in solar oscillation power spectra are not Lorentzian in shape, but have a distinct asymmetry. Fitting a symmetric Lorentzian profile to the peaks therefore produces a shift in frequency of the modes. Accurate determination of low-frequency modes is essential to infer the structure of the solar core by inversion of the mode frequencies. In this paper we investigate how the changes in frequencies of low-degree modes obtained by fitting symmetric and asymmetric peak profiles change the inferred properties of the solar core. We use data obtained by the Global Oscillations at Low Frequencies (GOLF) project on board the SoHO spacecraft. Two different solar models and inversion procedures are used to invert the data to determine the sound speed in the solar core. We find that for a given set of modes no significant difference in the inferred sound-speed results from taking asymmetry into account when fitting the low-degree modes., To appear in ApJ
Published: 2000
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38. The response of the magnetosphere to the passage of a coronal mass ejection on March 20-21, 1990

Author: Delores J. Knipp, Tim K. Yeoman, Barbara A. Emery, D. Orr, H. Lühr, S. I. Solovyev, T. J. Hughes, Mark Lester, J. R. Taylor, EGU, Publication, Department of Physics and Astronomy [Leicester], University of Leicester, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Department of Physics, Okayama University, Institute of Cosmophysical Research and Aeronomy, 31 Lenin Avenue., NRC Herzberg Institute of Astrophysics, National Research Council of Canada (NRC), Institut für Geophysik und Meteorologie [Braunschweig], and Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Magnetosphere, 550 - Earth sciences, 01 natural sciences, 0103 physical sciences, Substorm, Earth and Planetary Sciences (miscellaneous), Coronal mass ejection, Interplanetary magnetic field, 010303 astronomy & astrophysics, Ring current, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, Geology, Astronomy and Astrophysics, Geophysics, Solar wind, Earth's magnetic field, 13. Climate action, Space and Planetary Science, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Magnetopause
Abstract: International audience; The geomagnetic response to the passage of a coronal mass ejection (CME) is studied. The passage of the CME resulted in a storm sudden commencement (SSC) at 2243 UT on March 20 1990 with disturbed magnetic activity during the following 24 h. The auroral, sub-auroral and equatorial magnetic response to the southward turning at 1314 (±5) UT on March 21 and the equatorial response to the southward turning associated with the SSC on 20 March are discussed in terms of existing models. It is found that the auroral and sub-auroral response to the southward turning associated with the SSC is a factor 2 or more quicker than normal due to the shock in the solar wind dynamic pressure. The low-latitude response time to the southward turning, characterised by Dst and the magnetopause current corrected Dst*, is unaffected by the shock. Dst and Dst*, characteristic of the equatorial magnetic field, responded to the 1314 (±5) UT southward turning prior to the first observed substorm expansion phase onset, suggesting that a dayside loading process was responsible for the initial enhancement in the ring current rather than nightside particle injection. The response time of the auroral and sub-auroral magnetic field to the southward turning at 1314 (±5) UT on March 21 is measured at a variety of longitudes and latitudes. The azimuthal propagation velocity of the response to the southward turning varied considerably with latitude, ranging from ~8 km s?1 at 67°N to ~4 km s?1 at 55°N. The southward velocity of the equatorward boundary of the northern polar convection pattern has been measured. This velocity was ~1.2 km s?1 at 1600 MLT, although there was evidence that this may vary at different local times.
Published: 1997

39. First Results from SWAN Lyman α solar wind mapper on SOHO

Author: Bertaux, Jean-Loup, Quémerais, Eric, Lallement, Rosine, Kyrölä, E., Schmidt, Walter, Summanen, T., Goutail, Jean-Pierre, Berthé, Michell, Costa, Jorge, HOLZER, T., Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Finnish Meteorological Institute (FMI), High Altitude Observatory (HAO), and National Center for Atmospheric Research [Boulder] (NCAR)
Subjects: [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics, Astrophysics::Galaxy Astrophysics
Abstract: International audience; After one year of almost flawless operation on board the SOHO spacecraft poised at L1 Lagrange point, we report the main features of SWAN observations. SWAN is mainly dedicated to the monitoring of the latitude distribution of the solar wind by the Lα method. Maps of sky Lα emissions were recorded througout the year. The region of maximum emission, located in the upwind hemisphere, deviates strongly from the pattern that could be expected from a solar wind constant with latitude. It is divided into two lobes by a depression aligned with the solar equatorial plane called the Lyα groove already noted in 1976 Prognoz data. The north lobe is much brighter than the south lobe. These two characteristics can be explained qualitatively by an enhanced ionization along the neutral sheet where the slow solar wind is concentrated, which results from the higher low-latitude solar wind mass flux as measured by Ulysses. The groove is the direct imprint on the sky of the enhanced carving by the slow solar wind, at this time of solar minimum, when the tilt angle of the neutral sheet is small. The question is still pending to predict what will happen with the ascending phase of the solar cycle. Observations of comets are briefly mentioned, with the ability of SWAN to monitor the H2O production of many comets. Operations of the instrument are briefly described, including some instrumental problems which could be solved by software modifications sent to the instrument.
Published: 1997
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40. Long-Term Variation of the Interplanetary H Lyα Glow: Voyager UVS Measurements and Implications for the Solar H Lyα Irradiance

Author: Bill R. Sandel, Eric Quémerais, Giuliana de Toma, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), and University of Arizona
Subjects: Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Irradiance, Interplanetary medium, Flux, Astronomy and Astrophysics, Astrophysics, Solar irradiance, Atmospheric sciences, 01 natural sciences, Atmosphere, Atmospheric radiative transfer codes, 13. Climate action, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Solstice, Astrophysics::Earth and Planetary Astrophysics, Interplanetary spaceflight, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; In this paper we study interplanetary (IP) Lya data taken with the Voyager 1 and Voyager 2 spacecraft from 1980 to 1995. The coverage in time is equal to about 156 and 220 points yr~1 for Voyager 1 and Voyager 2, respectively, with almost no gaps. The IP Lya data are normalized for spatial changes in the emissivity, which arise from variations in observing geometry, by using a radiative transfer model. The normalized data show the variation of the solar H Lya line-center Ñux during the solar cycle. We compare this variation with the solar H Lya irradiance measurements of integrated Ñux from the Solar Mesosphere Explorer and the Upper Atmosphere Research Satellite/Solar-Stellar Irradiance Comparison Experiment (SOLSTICE), and, when direct solar measurements are not available, we use estimated irra-diances from magnesium and helium indices. The comparison between Voyager IP data and solar data shows that the best agreement is found with the SOLSTICE set of measurements, when no di †erences in the variation of the line-center Ñux and the integrated Ñux are taken into account.
Published: 1997
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41. STELLAR AGES AND CONVECTIVE CORES IN FIELD MAIN-SEQUENCE STARS: FIRST ASTEROSEISMIC APPLICATION TO TWOKEPLERTARGETS

Author: Yveline Lebreton, V. Silva Aguirre, Santi Cassisi, Aldo Serenelli, Dennis Stello, Jérôme Ballot, A. Weiss, Margarida S. Cunha, I. M. Brandão, Travis S. Metcalfe, Hans Kjeldsen, Timothy R. White, S. G. Sousa, Jørgen Christensen-Dalsgaard, Steven D. Kawaler, Thierry Appourchaux, Sarbani Basu, O. L. Creevey, Luca Casagrande, William J. Chaplin, Alfred F. Noels, Rafael A. García, G. Doğan, S. Deheuvels, Stellar Astrophysics Centre [Aarhus] (SAC), Aarhus University [Aarhus], High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), School of Physics and Astronomy, University of Birmingham [Birmingham], Max-Planck-Institut für Radioastronomie (MPIFR), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Funding for this Discovery mission is provided by NASA's Science Mission Directorate. The authors wish to thank the entire Kepler team, without whom these results would not be possible. We also thank all funding councils and agencies that have supported the activities of KASC Working Group 1. We are also grateful for support from the International Space Science Institute (ISSI). The authors acknowledge the KITP staff of UCSB for their warm hospitality during the research program 'Asteroseismology in the Space Age.' This KITP program was supported in part by the National Science Foundation of the United States under grant No. NSF PHY0551164. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (grant agreement No. DNRF106). The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement No. 267864). V.S.A. received financial support from the Excellence cluster 'Origin and Structure of the Universe' (Garching). S.B. acknowledges NSF grant AST-1105930. The National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation. I.M.B., M.S.C., and S.G.S. acknowledge the support from the Fundacão para a Ciência e Tecnologia (Portugal) through the grants SFRH/BD/41213/2007, SFRH/BPD/47611/2008 and SFRH/BPD/84810/2012 and the ERC, under FP7/EC, through the project FP7-SPACE-2012-312844. T.S.M. acknowledges support from NASA grant NNX09AE59G. A.M.S is partially supported by the European Union International Reintegration Grant PIRG-GA-2009-247732, the MICINN grant AYA2011-24704, by the ESF EUROCORES Program EuroGENESIS (MICINN grant EUI2009-04170), by SGR grants of the Generalitat de Catalunya and by the EU-FEDER funds. W.J.C. acknowledges support from the UK Science and Technology Facilities Council (STFC). This research was carried out while O.L.C. was a Henri Poincaré Fellow at the Observatoire de la Côte d'Azur, partially funded by the Conseil Général des Alpes-Maritimes. R.A.G. acknowledges the funding from the European CommunityÕs Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 269194 (IRSES/ASK)., European Project, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: oscillations [stars], Convection, Field (physics), fundamental parameters [stars], FOS: Physical sciences, Boundary (topology), asteroseismology, Astrophysics, stars: interiors, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), interiors [stars], [PHYS]Physics [physics], Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Oscillation, Astronomy and Astrophysics, Radius, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), stars: fundamental parameters, stars: oscillations, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Main sequence
Abstract: Using asteroseismic data and stellar evolution models we make the first detection of a convective core in a Kepler field main-sequence star, putting a stringent constraint on the total size of the mixed zone and showing that extra mixing beyond the formal convective boundary exists. In a slightly less massive target the presence of a convective core cannot be conclusively discarded, and thus its remaining main-sequence life time is uncertain. Our results reveal that best-fit models found solely by matching individual frequencies of oscillations corrected for surface effects do not always properly reproduce frequency combinations. Moreover, slightly different criteria to define what the best-fit model is can lead to solutions with similar global properties but very different interior structures. We argue that the use of frequency ratios is a more reliable way to obtain accurate stellar parameters, and show that our analysis in field main-sequence stars can yield an overall precision of 1.5%, 4%, and 10% in radius, mass and age, respectively. We compare our results with those obtained from global oscillation properties, and discuss the possible sources of uncertainties in asteroseismic stellar modeling where further studies are still needed., 46 pages, 10 figures, ApJ accepted
Published: 2013
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42. The discovery of nonradial pulsation in the λ Bootis star HD 111604

Author: Bohlender, David A., Gonzalez, Jean-François, Kennelly, E., Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), High Altitude Observatory (HAO), and National Center for Atmospheric Research [Boulder] (NCAR)
Subjects: stars: individual: HD 111604, stars: λ Boo, stars: oscillations, stars: peculiar A, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], stars: δ Scuti
Abstract: International audience; Evidence for high order nonradial pulsation (NRP) has been discovered in the λ Boo star HD 111604. Analysis of a limited number of spectra of the NaID lines indicate that the mode of oscillation, |m|, is approximately 20 and NRP features circumnavigate the star every 0.71 days. Current models suggest that these objects should be near the ZAMS, and the detection of nonradial pulsation in at least one member of the class presents the exciting possibility of performing a direct measurement of its evolutionary state to test this hypothesis.
Published: 1996

43. Kepler detected gravity-mode period spacings in a red giant star

Author: Arlette Noels, Thomas Kallinger, Josefina Montalbán, Fabien Carrier, Saskia Hekker, Hans Kjeldsen, J. De Ridder, Yvonne Elsworth, Paul G. Beck, Timothy R. Bedding, Savita Mathur, Jon M. Jenkins, Benoit Mosser, Dennis Stello, Andrea Miglio, Marc-Antoine Dupret, Rafael A. García, S. Frandsen, S. D. Kawaler, Daniel Huber, Timothy M. Brown, William J. Chaplin, Timothy R. White, Jørgen Christensen-Dalsgaard, Conny Aerts, R. L. Gilliland, Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Sydney Institute for Astronomy (SIfA), The University of Sydney, 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), 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), Department of Physics and Astronomy [Vancouver], University of British Columbia (UBC), School of Physics and Astronomy, University of Birmingham [Birmingham], Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Department of Physics and Astronomy [Aarhus], Aarhus University [Aarhus], Space Telescope Science Institute (STSci), Las Cumbres Observatory Global Telescope, Department of Physics and Astronomy [Ames, Iowa], Iowa State University (ISU), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Search for Extraterrestrial Intelligence Institute (SETI), European Project: 227224,EC:FP7:ERC,ERC-2008-AdG,PROSPERITY(2009), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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 de Paris (UP), Low Energy Astrophysics (API, FNWI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), 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), and Stellar Astrophysics Centre [Aarhus] (SAC)
Subjects: Convection, Physics, Multidisciplinary, 010308 nuclear & particles physics, Oscillation, Red giant, Astronomy, Astrophysics, Giant star, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Core (optical fiber), Solar core, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Satellite, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Envelope (waves)
Abstract: Asteroseismology Delivers Using asteroseismology—the study of stellar oscillations, it is possible to probe the interior of stars and to derive stellar parameters, such as mass and radius (see the Perspective by Montgomery ). Based on asteroseismic data from the NASA Kepler mission, Chaplin et al. (p. 213 ) detected solarlike oscillations in 500 solartype stars in our Galaxy. The distribution of the radii of these stars matches that expected from stellar evolution theory, but the distribution in mass does not, which challenges our knowledge of star formation rates, the mass of forming stars, and the models of the stars themselves. Derekas et al. (p. 216 ) report the detection of a triple-star system comprising a red giant star and two red dwarfs. The red giant star, instead of the expected solarlike oscillations, shows evidence for tidally induced oscillations driven by the orbital motion of the red dwarf pair. Finally, Beck et al. (p. 205 ) describe unusual oscillations from a red giant star that may elucidate characteristics of its core.
Published: 2011
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44. Proton transport model in the ionosphere. 2. Influence of magnetic mirroring and collisions on the angular redistribution in a proton beam

Author: Dirk Lummerzheim, Wlodek Kofman, Marina Galand, Jean Lilensten, High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), Intégration des Systèmes de Puissance en 3 Dimensions (ISP3D), École normale supérieure - Cachan (ENS Cachan)-Université de Lille, Sciences et Technologies-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-ENSEEIHT, Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-École Nationale Supérieure d'Ingénieurs Électriciens de Grenoble (ENSIEG)-Centre National de la Recherche Scientifique (CNRS), Geophysical Institute [Fairbanks], and University of Alaska [Fairbanks] (UAF)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Proton, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Inelastic scattering, 01 natural sciences, symbols.namesake, Optics, Proton transport, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Pitch angle, Spectral resolution, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Elastic scattering, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, business.industry, Scattering, lcsh:QC801-809, Geology, Astronomy and Astrophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, symbols, lcsh:Q, Atomic physics, business, Doppler effect, lcsh:Physics
Abstract: We investigate the influence of magnetic mirroring and elastic and inelastic scattering on the angular redistribution in a proton/hydrogen beam by using a transport code in comparison with observations. H-emission Doppler profiles viewed in the magnetic zenith exhibit a red-shifted component which is indicative of upward fluxes. In order to determine the origin of this red shift, we evaluate the influence of two angular redistribution sources which are included in our proton/hydrogen transport model. Even though it generates an upward flux, the redistribution due to magnetic mirroring effect is not sufficient to explain the red shift. On the other hand, the collisional angular scattering induces a much more significant red shift in the lower atmosphere. The red shift due to collisions is produced by Key words. Auroral ionosphere · Particle precipitation

45. Review of mesospheric temperature trends

Author: Gufran Beig, Keckhut, P., Lowe, R. P., Roble, R. G., Mlynczak, M. G., Scheer, J., Fomichev, V. I., Offermann, D., French, W. J. R., Shepherd, M. G., Semenov, A. I., Remsberg, E. E., She, C. Y., Lübken, F. J., Bremer, J., Clemesha, B. R., Stegman, J., Sigernes, F., Fadnavis, S., Indian Institute of Tropical Meteorology (IITM), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Western Ontario (UWO), High Altitude Observatory (HAO), National Center for Atmospheric Research [Boulder] (NCAR), NASA Langley Research Center [Hampton] (LaRC), Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), Department of Earth and Atmospheric Science [Toronto], York University [Toronto], Department of Physics, Faculty of Mathematics und Natural Sciences [Wuppertal], University of Wuppertal, Australian Antarctic Division (AAD), Australian Government, Department of the Environment and Energy, Centre for Research in Earth and Space Science [Toronto] (CRESS), A.M.Obukhov Institute of Atmospheric Physics (IAP), Russian Academy of Sciences [Moscow] (RAS), Department of Physics [Fort Collins], Colorado State University [Fort Collins] (CSU), Leibniz-Institut für Atmosphärenphysik (IAP), Universität Rostock-Leibniz Association, Instituto Nacional de Pesquisas Espaciais (INPE), Ministério da Ciência, Tecnologia e Inovação, Department of Meteorology [Stockholm] (MISU), Stockholm University, and The University Centre in Svalbard (UNIS)
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], density, et al, temperature trends, thermal shrinking, 1630 Global Change: Impact phenomena, greenhouse gases Citation: Beig, 0325), 0350 Atmospheric Composition and Structure: Pressure, TERMS: 1610 Global Change: Atmo- sphere (0315, greenhouse gases, and tem- perature, 0342 Atmospheric Composition and Structure: Middle at- mosphere– energy deposition, 0325 Atmospheric Composition and Structure: Evolution of the atmosphere, KEYWORDS: temperature trends, mesosphere, Review of mesospheric temperature trends
Abstract: International audience; In recent times it has become increasingly clear thatreleases of trace gases from human activity have a potentialfor causing change in the upper atmosphere. However,our knowledge of systematic changes and trends inthe temperature of the mesosphere and lower thermosphereis relatively limited compared to the Earths loweratmosphere, and not much effort has been made to synthesizethese results so far. In this article, a comprehensivereview of long-term trends in the temperature of the regionfrom 50 to 100 km is made on the basis of the availableup-to-date understanding of measurements and model calculations.An objective evaluation of the available datasets is attempted, and important uncertainly factors arediscussed. Some natural variability factors, which arelikely to play a role in modulating temperature trends,are also briefly touched upon. There are a growing numberof experimental results centered on, or consistent with,zero temperature trend in the mesopause region (80–100km). The most reliable data sets show no significant trendbut an uncertainty of at least 2 K/decade. On the otherhand, a majority of studies indicate negative trends inthe lower and middle mesosphere with an amplitude ofa few degrees (2–3 K) per decade. In tropical latitudesthe cooling trend increases in the upper mesosphere.The most recent general circulation models indicateincreased cooling closer to both poles in the middlemesosphere and a decrease in cooling toward the summerpole in the upper mesosphere. Quantitatively, thesimulated cooling trend in the middle mesosphere producedonly by CO2 increase is usually below the observedlevel. However, including other greenhouse gasesand taking into account a “thermal shrinking” of theupper atmosphere result in a cooling of a few degreesper decade. This is close to the lower limit of the observednonzero trends. In the mesopause region, recentmodel simulations produce trends, usually below 1 K/decade,that appear to be consistent with most observationsin this region
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46. Alfven waves in the solar corona.

Author: Tomczyk S, McIntosh SW, Keil SL, Judge PG, Schad T, Seeley DH, and Edmondson J
Abstract: Alfvén waves, transverse incompressible magnetic oscillations, have been proposed as a possible mechanism to heat the Sun's corona to millions of degrees by transporting convective energy from the photosphere into the diffuse corona. We report the detection of Alfvén waves in intensity, line-of-sight velocity, and linear polarization images of the solar corona taken using the FeXIII 1074.7-nanometer coronal emission line with the Coronal Multi-Channel Polarimeter (CoMP) instrument at the National Solar Observatory, New Mexico. Ubiquitous upward propagating waves were seen, with phase speeds of 1 to 4 megameters per second and trajectories consistent with the direction of the magnetic field inferred from the linear polarization measurements. An estimate of the energy carried by the waves that we spatially resolved indicates that they are too weak to heat the solar corona; however, unresolved Alfvén waves may carry sufficient energy.
Published: 2007
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