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49 results on '"Le Bouquin, Jean-Baptiste"'

1. Imaging the warped dusty disk wind environment of SU Aurigae with MIRC-X

Author: Labdon, Aaron, primary, Kraus, Stefan, additional, Davies, Claire L., additional, Kreplin, Alexander, additional, Zarrilli, Sebastian, additional, Monnier, John D., additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, Setterholm, Benjamin, additional, Gardner, Tyler, additional, Ennis, Jacob, additional, Lanthermann, Cyprien, additional, ten Brummelaar, Theo, additional, Schaefer, Gail, additional, and Harries, Tim J., additional
Published: 2023
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2. Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog

Author: Korolik, Maria, primary, Roettenbacher, Rachael M., additional, Fischer, Debra A., additional, Kane, Stephen R., additional, Perkins, Jean M., additional, Monnier, John D., additional, Davies, Claire L., additional, Kraus, Stefan, additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, Gardner, Tyler, additional, Lanthermann, Cyprien, additional, Schaefer, Gail H., additional, Setterholm, Benjamin, additional, Brewer, John M., additional, Llama, Joe, additional, Zhao, Lily L., additional, Szymkowiak, Andrew E., additional, and Henry, Gregory W., additional
Published: 2023
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3. The Great Dimming of the Hypergiant Star RW Cephei: CHARA Array Images and Spectral Analysis

Author: Anugu, Narsireddy, primary, Baron, Fabien, additional, Gies, Douglas R., additional, Lanthermann, Cyprien, additional, Schaefer, Gail H., additional, Shepard, Katherine A., additional, Brummelaar, Theo ten, additional, Monnier, John D., additional, Kraus, Stefan, additional, Le Bouquin, Jean-Baptiste, additional, Davies, Claire L., additional, Ennis, Jacob, additional, Gardner, Tyler, additional, Labdon, Aaron, additional, Roettenbacher, Rachael M., additional, Setterholm, Benjamin R., additional, Vollmann, Wolfgang, additional, and Sigismondi, Costantino, additional
Published: 2023
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4. Three-dimensional Orbit of AC Her Determined: Binary-induced Truncation Cannot Explain the Large Cavity in This Post-AGB Transition Disk

Author: Anugu, Narsireddy, primary, Kluska, Jacques, additional, Gardner, Tyler, additional, Monnier, John D., additional, Van Winckel, Hans, additional, Schaefer, Gail H., additional, Kraus, Stefan, additional, Le Bouquin, Jean-Baptiste, additional, Ertel, Steve, additional, Mérand, Antoine, additional, Klement, Robert, additional, Davies, Claire L, additional, Ennis, Jacob, additional, Labdon, Aaron, additional, Lanthermann, Cyprien, additional, Setterholm, Benjamin R., additional, Brummelaar, Theo ten, additional, Corporaal, Akke, additional, Sabin, Laurence, additional, and Rajagopal, Jayadev, additional
Published: 2023
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5. Imaging the Inner Astronomical Unit of the Herbig Be Star HD 190073

Author: Ibrahim, Nour, primary, Monnier, John D., additional, Kraus, Stefan, additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, Baron, Fabien, additional, Brummelaar, Theo Ten, additional, Davies, Claire L., additional, Ennis, Jacob, additional, Gardner, Tyler, additional, Labdon, Aaron, additional, Lanthermann, Cyprien, additional, Mérand, Antoine, additional, Rich, Evan, additional, Schaefer, Gail H., additional, and Setterholm, Benjamin R., additional
Published: 2023
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6. The Orbits and Dynamical Masses of the Castor System

Author: Torres, Guillermo, primary, Schaefer, Gail H., additional, Monnier, John D., additional, Anugu, Narsireddy, additional, Davies, Claire L., additional, Ennis, Jacob, additional, Farrington, Christopher D., additional, Gardner, Tyler, additional, Klement, Robert, additional, Kraus, Stefan, additional, Labdon, Aaron, additional, Lanthermann, Cyprien, additional, Le Bouquin, Jean-Baptiste, additional, Setterholm, Benjamin R., additional, and ten Brummelaar, Theo, additional
Published: 2022
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7. The Small Separation A-star Companion Population: First Results with CHARA/MIRC-X

Author: De Furio, Matthew, primary, Gardner, Tyler, additional, Monnier, John, additional, Meyer, Michael R., additional, Kratter, Kaitlin, additional, Schaefer, Gail, additional, Anugu, Narsireddy, additional, Davies, Claire L., additional, Kraus, Stefan, additional, Lanthermann, Cyprien, additional, Le Bouquin, Jean-Baptiste, additional, and Ennis, Jacob, additional
Published: 2022
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8. The binary system of the spinning-top Be star Achernar

Author: Kervella, Pierre, primary, Borgniet, Simon, additional, de Souza, Armando Domiciano, additional, Mérand, Antoine, additional, Gallenne, Alexandre, additional, Rivinius, Thomas, additional, Lacour, Sylvestre, additional, Carciofi, Alex, additional, Faes, Daniel Moser, additional, Le Bouquin, Jean-Baptiste, additional, Taormina, Monica, additional, Pilecki, Bogumił, additional, Berger, Jean-Philippe, additional, Bendjoya, Philippe, additional, Klement, Robert, additional, Millour, Florentin, additional, Janot-Pacheco, Eduardo, additional, Spang, Alain, additional, and Vakili, Farrokh, additional
Published: 2022
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9. ARMADA. II. Further Detections of Inner Companions to Intermediate-mass Binaries with Microarcsecond Astrometry at CHARA and VLTI

Author: Gardner, Tyler, primary, Monnier, John D., additional, Fekel, Francis C., additional, Le Bouquin, Jean-Baptiste, additional, Scovera, Adam, additional, Schaefer, Gail, additional, Kraus, Stefan, additional, Adams, Fred C., additional, Anugu, Narsireddy, additional, Berger, Jean-Philippe, additional, Ten Brummelaar, Theo, additional, Davies, Claire L., additional, Ennis, Jacob, additional, Gies, Douglas R., additional, Johnson, Keith J. C., additional, Kervella, Pierre, additional, Kratter, Kaitlin M., additional, Labdon, Aaron, additional, Lanthermann, Cyprien, additional, Sahlmann, Johannes, additional, and Setterholm, Benjamin R., additional
Published: 2022
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10. Characterising the orbit and circumstellar environment of the high-mass binary MWC 166 A

Author: Zarrilli, Sebastian A., primary, Kraus, Stefan, additional, Kreplin, Alexander, additional, Monnier, John D., additional, Gardner, Tyler, additional, Mérand, Antoine, additional, Morrell, Sam, additional, Davies, Claire L., additional, Labdon, Aaron, additional, Ennis, Jacob, additional, Setterholm, Benjamin, additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, Lanthermann, Cyprien, additional, Schaefer, Gail, additional, and ten Brummelaar, Theo, additional
Published: 2022
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11. The Interferometric Binary ϵ Cnc in Praesepe: Precise Masses and Age

Author: Morales, Leslie M., primary, Sandquist, Eric L., additional, Schaefer, Gail H., additional, Farrington, Christopher D., additional, Klement, Robert, additional, Bedin, Luigi R., additional, Libralato, Mattia, additional, Malavolta, Luca, additional, Nardiello, Domenico, additional, Orosz, Jerome A., additional, Monnier, John D., additional, Kraus, Stefan, additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, ten Brummelaar, Theo, additional, Davies, Claire L., additional, Ennis, Jacob, additional, Gardner, Tyler, additional, and Lanthermann, Cyprien, additional
Published: 2022
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12. Interferometric Detections of sdO Companions Orbiting Three Classical Be Stars

Author: Klement, Robert, primary, Schaefer, Gail H., additional, Gies, Douglas R., additional, Wang, Luqian, additional, Baade, Dietrich, additional, Rivinius, Thomas, additional, Gallenne, Alexandre, additional, Carciofi, Alex C., additional, Monnier, John D., additional, Mérand, Antoine, additional, Anugu, Narsireddy, additional, Kraus, Stefan, additional, Davies, Claire L., additional, Lanthermann, Cyprien, additional, Gardner, Tyler, additional, Wysocki, Peter, additional, Ennis, Jacob, additional, Labdon, Aaron, additional, Setterholm, Benjamin R., additional, and Le Bouquin, Jean-Baptiste, additional
Published: 2022
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13. GRAVITY plus Wide: Towards hundreds of z similar to 2 AGN

Author: Drescher, Antonia, Fabricius, Maximilian, Shimizu, Taro, Woillez, Julien, Bourget, Pierre, Widmann, Felix, Shangguan, Jingyi, Straubmeier, Christian, Horrobin, Matthew, Schuhler, Nicolas, Eisenhauer, Frank, Gonte, Frederic, Gillessen, Stefan, Ott, Thomas, Perrin, Guy, Paumard, Thibaut, Brandner, Wolfgang, Kreidberg, Laura, Perraut, Karine, Le Bouquin, Jean-Baptiste, Garcia, Paulo, Honig, Sebastian, Defrere, Denis, Bourdarot, Guillaume, Feuchtgruber, Helmut, Genzel, Reinhard, Hartl, Michael, Haussmann, Frank, Lutz, Dieter, More, Nikhil, Rau, Christian, Sauter, Jonas, Uysal, Sinem, Wessely, Patrick, Wieprecht, Ekkehard, Wimmer, Lukas, Yazici, Senol, Merand, A, Sallum, S, and Sanchez-Bermudez, J
Subjects: Technology, Science & Technology, GRAVITY, Physical Sciences, Optics, Astronomy & Astrophysics, interferometry, Instruments & Instrumentation, near-infrared, wide-angle fringe tracking, VLTI
Abstract: ispartof: OPTICAL AND INFRARED INTERFEROMETRY AND IMAGING VIII vol:12183 ispartof: Conference on Optical and Infrared Interferometry and Imaging VIII Part of SPIE Astronomical Telescopes and Instrumentation Conference location:CANADA, Montreal date:17 Jul - 22 Jul 2022 status: published
Published: 2022

14. Scattering and sublimation: A multi-scale view of micron sized dust in the inclined disc of HD 145718

Author: Davies, Claire L, Rich, Evan A, Harries, Tim, Monnier, John, Laws, Anna, Andrews, Sean M, Bae, Jaehan, Wilner, David J, Anugu, Narsireddy, Ennis, Jacob, Gardner, Tyler, Kraus, Stefan, Labdon, Aaron, le Bouquin, Jean Baptiste, Lanthermann, Cyprien, Schaefer, Gail H, Setterholm, Benjamin R, and ten Brummelaar, Theo
Subjects: Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Highly inclined protoplanetary discs provide unique perspectives on dust evolution, allowing the vertical extent of the disc to be directly assessed. Further, polarised differential imaging (PDI) of highly inclined discs can probe the size distribution of grains in the disc's surface layers due to the size-dependence of the scattering phase function. I present our analysis of our multi-instrument observations of the highly inclined protoplanetary disc around Herbig Ae star HD 145718. By comparing synthetic images to our GPI PDI observations, we show that a reasonable assessment of the height of the scattering surface can be obtained by fitting ellipses to isophotes of $Q_{\phi}$ surface brightness. Moreover, we show this method has the potential to probe the degree of flaring in the scattering surface if the inclination is sufficiently well constrained. We use the TORUS radiative transfer code to examine the grain size distribution in the scattering surface. Our models are further constrained using an SED, constructed from archival photometry, and new and archival CHARA/MIRC-X, VLTI/GRAVITY and VLTI/PIONIER near-infrared interferometry. For typical ISM prescriptions of grain size number density, we find the largest grains in the scattering surface are ~0.5 microns in size. Larger grains have likely settled closer to the disc midplane. At the inner edge of the disc, the larger settled grains shelter small grains, allowing the sublimation rim to extend down to 0.17 au. The smaller grains emerge at larger scale heights beyond ~0.40 au.
Published: 2021
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15. EXPRES. III. Revealing the Stellar Activity Radial Velocity Signature of ϵ Eridani with Photometry and Interferometry

Author: Roettenbacher, Rachael M., primary, Cabot, Samuel H. C., additional, Fischer, Debra A., additional, Monnier, John D., additional, Henry, Gregory W., additional, Harmon, Robert O., additional, Korhonen, Heidi, additional, Brewer, John M., additional, Llama, Joe, additional, Petersburg, Ryan R., additional, Zhao, Lily L., additional, Kraus, Stefan, additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, Davies, Claire L., additional, Gardner, Tyler, additional, Lanthermann, Cyprien, additional, Schaefer, Gail, additional, Setterholm, Benjamin, additional, Clark, Catherine A., additional, Jorstad, Svetlana G., additional, Kuehn, Kyler, additional, and Levine, Stephen, additional
Published: 2021
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16. The surface magnetic field topologies of both M-dwarf components from the double-line spectroscopic binary FK Aqr

Author: Tsvetkova, Svetla, Morin, Julien, Folsom, Colin, Alecian, Evelyne, Hussain, Gaitee, Le Bouquin, Jean-Baptiste, Neiner, Coralie, Wade, Gregg, Collaboration, The BinaMIcS, and Wolk, Scott
Subjects: Cool Stars on the main sequence, Astrophysics::Solar and Stellar Astrophysics, Binary, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: This study is part of the BinaMIcS project which aims to understand the interaction between binarity and magnetism in different type of stars. Here, we present FK Aqr (GJ 867 A) – a double-line spectroscopic binary system consisting of two dM1-dwarfs with similar masses (0.55 Msun and 0.45 Msun for the primary and secondary, respectively). We were able to reconstruct the first maps of the surface magnetic field topologies of both components by employing the Zeeman Doppler imaging method. The data were obtained with ESPaDOnS spectropolarimeter at CFHT. Clear Stokes V signatures are detected from all observations of both components. The longitudinal magnetic field of the secondary is two times stronger than the primary’s one. The reconstructed maps show that both M-dwarfs have dipolar structures of their large-scale magnetic fields. This is in agreement with previous studies showing that M-dwarf stars, even in close binary pairs, can generate surface magnetic fields displaying a strong axisymmetric dipole component. We also note that the components of FK Aqr are among the most massive M-dwarfs known to generate this type of magnetic field. Orbital parameters of the system are refined employing the PHOEBE software based on the measurements of the radial velocities of both components from the mean Stokes I profiles.
Published: 2021
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17. Compensation of differential dispersion: application to multiband stellar interferometry

Author: Pannetier, Cyril, primary, Mourard, Denis, additional, Cassaing, Frédéric, additional, Lagarde, Stéphane, additional, Le Bouquin, Jean-Baptiste, additional, Monnier, John, additional, Sturmann, Judit, additional, and Ten Brummelaar, Theo, additional
Published: 2021
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18. ν Gem: A Hierarchical Triple System with an Outer Be Star

Author: Klement, Robert, primary, Hadrava, Petr, additional, Rivinius, Thomas, additional, Baade, Dietrich, additional, Cabezas, Mauricio, additional, Heida, Marianne, additional, Schaefer, Gail H., additional, Gardner, Tyler, additional, Gies, Douglas R., additional, Anugu, Narsireddy, additional, Lanthermann, Cyprien, additional, Davies, Claire L., additional, Anderson, Matthew D., additional, Monnier, John D., additional, Ennis, Jacob, additional, Labdon, Aaron, additional, Setterholm, Benjamin R., additional, Kraus, Stefan, additional, ten Brummelaar, Theo A., additional, and Le Bouquin, Jean-Baptiste, additional
Published: 2021
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19. The Interferometric Binary Ďµ Cnc in Praesepe: Precise Masses and Age.

Author: Morales, Leslie M., Sandquist, Eric L., Schaefer, Gail H., Farrington, Christopher D., Klement, Robert, Bedin, Luigi R., Libralato, Mattia, Malavolta, Luca, Nardiello, Domenico, Orosz, Jerome A., Monnier, John D., Kraus, Stefan, Le Bouquin, Jean-Baptiste, Anugu, Narsireddy, ten Brummelaar, Theo, Davies, Claire L., Ennis, Jacob, Gardner, Tyler, and Lanthermann, Cyprien
Published: 2022
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20. The orbit and stellar masses of the archetype colliding-wind binary WR 140

Author: Thomas, Joshua D, primary, Richardson, Noel D, additional, Eldridge, J J, additional, Schaefer, Gail H, additional, Monnier, John D, additional, Sana, Hugues, additional, Moffat, Anthony F J, additional, Williams, Peredur, additional, Corcoran, Michael F, additional, Stevens, Ian R, additional, Weigelt, Gerd, additional, Zainol, Farrah D, additional, Anugu, Narsireddy, additional, Le Bouquin, Jean-Baptiste, additional, ten Brummelaar, Theo, additional, Campos, Fran, additional, Couperus, Andrew, additional, Davies, Claire L, additional, Ennis, Jacob, additional, Eversberg, Thomas, additional, Garde, Oliver, additional, Gardner, Tyler, additional, Fló, Joan Guarro, additional, Kraus, Stefan, additional, Labdon, Aaron, additional, Lanthermann, Cyprien, additional, Leadbeater, Robin, additional, Lester, T, additional, Maki, Courtney, additional, McBride, Brendan, additional, Ozuyar, Dogus, additional, Ribeiro, J, additional, Setterholm, Benjamin, additional, Stober, Berthold, additional, Wood, Mackenna, additional, and Zurmühl, Uwe, additional
Published: 2021
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21. Viscous heating in the disk of the outbursting star FU Orionis

Author: Labdon, Aaron, primary, Kraus, Stefan, additional, Davies, Claire L., additional, Kreplin, Alexander, additional, Monnier, John D., additional, Le Bouquin, Jean-Baptiste, additional, Anugu, Narsireddy, additional, ten Brummelaar, Theo, additional, Setterholm, Benjamin, additional, Gardner, Tyler, additional, Ennis, Jacob, additional, Lanthermann, Cyprien, additional, Schaefer, Gail, additional, and Laws, Anna, additional
Published: 2021
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22. ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem

Author: Gardner, Tyler, primary, Monnier, John D., additional, Fekel, Francis C., additional, Schaefer, Gail, additional, Johnson, Keith J. C., additional, Le Bouquin, Jean-Baptiste, additional, Kraus, Stefan, additional, Anugu, Narsireddy, additional, Setterholm, Benjamin R., additional, Labdon, Aaron, additional, Davies, Claire L., additional, Lanthermann, Cyprien, additional, Ennis, Jacob, additional, Ireland, Michael, additional, Kratter, Kaitlin M., additional, Ten Brummelaar, Theo, additional, Sturmann, Judit, additional, Sturmann, Laszlo, additional, Farrington, Chris, additional, Gies, Douglas R., additional, Klement, Robert, additional, and Adams, Fred C., additional
Published: 2020
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23. MIRC-X: A Highly Sensitive Six-telescope Interferometric Imager at the CHARA Array

Author: Anugu, Narsireddy, primary, Le Bouquin, Jean-Baptiste, additional, Monnier, John D., additional, Kraus, Stefan, additional, Setterholm, Benjamin R., additional, Labdon, Aaron, additional, Davies, Claire L, additional, Lanthermann, Cyprien, additional, Gardner, Tyler, additional, Ennis, Jacob, additional, Johnson, Keith J. C., additional, Ten Brummelaar, Theo, additional, Schaefer, Gail, additional, and Sturmann, Judit, additional
Published: 2020
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24. Spin–Orbit Alignment of the β Pictoris Planetary System

Author: Kraus, Stefan, primary, Le Bouquin, Jean-Baptiste, additional, Kreplin, Alexander, additional, Davies, Claire L., additional, Hone, Edward, additional, Monnier, John D., additional, Gardner, Tyler, additional, Kennedy, Grant, additional, and Hinkley, Sasha, additional
Published: 2020
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25. Scattering and sublimation: a multiscale view of µm-sized dust in the inclined disc of HD 145718.

Author: Davies, Claire L, Rich, Evan A, Harries, Tim J, Monnier, John D, Laws, Anna S E, Andrews, Sean M, Bae, Jaehan, Wilner, David J, Anugu, Narsireddy, Ennis, Jacob, Gardner, Tyler, Kraus, Stefan, Labdon, Aaron, le Bouquin, Jean-Baptiste, Lanthermann, Cyprien, Schaefer, Gail H, Setterholm, Benjamin R, ten Brummelaar, Theo, and collaboration, G-LIGHTS
Subjects: SURFACE scattering, MINERAL dusts, RADIATIVE transfer, GEOMETRIC analysis, CIRCUMSTELLAR matter, STAR formation, DUST
Abstract: We present multi-instrument observations of the disc around the Herbig Ae star, HD 145718, employing geometric and Monte Carlo radiative transfer models to explore the disc orientation, the vertical and radial extent of the near-infrared (NIR) scattering surface, and the properties of the dust in the disc surface and sublimation rim. The disc appears inclined at 67–71°, with position angle, PA = −1.0 to 0.6°, consistent with previous estimates. The NIR scattering surface extends out to |${\sim}75\,$| au and we infer an aspect ratio, h scat(r)/ r ∼ 0.24 in J band; ∼0.22 in H band. Our Gemini Planet Imager images and VLTI + CHARA NIR interferometry suggest that the disc surface layers are populated by grains ≳λ/2π in size, indicating these grains are aerodynamically supported against settling and/or the density of smaller grains is relatively low. We demonstrate that our geometric analysis provides a reasonable assessment of the height of the NIR scattering surface at the outer edge of the disc and, if the inclination can be independently constrained, has the potential to probe the flaring exponent of the scattering surface in similarly inclined (i ≳ 70°) discs. In re-evaluating HD 145718's stellar properties, we found that the object's dimming events – previously characterized as UX Or and dipper variability – are consistent with dust occultation by grains larger, on average, than found in the ISM. This occulting dust likely originates close to the inferred dust sublimation radius at |$0.17\,$| au. [ABSTRACT FROM AUTHOR]
Published: 2022
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26. Towards constraints on massive galactic stars using VLT/SPHERE with high-contrast imaging

Author: Rainot, Alan, Reggiani, Maddalena Maria, Sana, Hugues, Gomez-Gonzalez, Carlos, Absil, Olivier, Christiaens, Valentin, Delorme, Philippe, Almeida, Leonardo, Caballero-Nieves, Saida, De Ridder, Joris, Kratter, Kaitlin, Lacour, Sylvestre, Le Bouquin, Jean-Baptiste, Pueyo, Laurent, and Zinnecker, Hans
Abstract: While the formation of massive stars remains heavily debated, it is nowadays clear that the formation scenarios need to account for the high-degree of multiplicity of these objects that has been observed by recent studies. Here we introduce the Carina High-contrast Imaging Project for massive Stars (CHIPS) that aims to obtain coronagraphic observations of massive stars in the Carina region using VLT/SPHERE. We illustrate the capabilities of SPHERE for massive stars by focusing on the QZ Car system. We detect 19 sources, most of them for the first time, within a 7x7′′ field of view. We show that contrast better than 9 mag can be achieved at separation larger than 200 mas. We also investigate avenues to obtain a first characterisation of the detected sources by fitting their source energy distribution with pre-main sequence stellar atmosphere models ispartof: pages:366-373 ispartof: Journal of the Italian Astronomical Society / Memorie Della Società Astronomica Italiana vol:90 issue:3 pages:366-373 ispartof: EWASS 2019 location:Lyon, France status: published
Published: 2019

27. The ExoGRAVITY project: using single mode interferometry to characterize exoplanets

Author: Tuthill, Peter G., Mérand, Antoine, Sallum, Stephanie, Lacour, S., Wang, J. J., Nowak, Mathias, Pueyo, Laurent A., Eisenhauer, Frank, Lagrange, A.-M., Mollière, Paul, Abuter, Roberto, Amorin, António, Asensio-Torres, R., Baubock, Michi, Benisty, Myriam, Berger, Jean-Philippe, Beust, Hervé, Blunt, S., Boccaletti, Anthony, Bonnefoy, Mickaël, Bonnet, Henri, Brandner, Wolfgang, Cantalloube, Faustine, Caselli, Paola, Charnay, Benjamin, Chauvin, Gael, Choquet, Élodie, Christiaens, Valentin, Clénet, Yann, Cridland, Alex, de Zeeuw, Tim, Dembet, Roderick, Dexter, Jason, Drescher, Antonia, Duvert, Gilles, Gao, Feng, Garcia-Lopez, Rebeca, Gardner, Tyler, Gendron, Eric, Genzel, Reinhard, Gillessen, Stefan, Girard, Julien H., Haubois, Xavier, Heissel, Gernot, Henning, Thomas, Hinkley, Sasha, Hippler, Stefan, Horrobin, Matthew, Houlle, Matthis, Hubert, Zoltan, Jimenez Rosales, A, Jocou, Laurent, Kammerer, Jens, Keppler, Miriam, Kervella, Pierre, Kreidberg, Laura, Lapeyrere, Vincent, Le Bouquin, Jean-Baptiste, Léna, Pierre, Lutz, Dieter, Maire, Anne-Lise, Monnier, John, Mouillet, David, Muller, André, Nasedkin, E., Ott, Thomas, Otten, Gilles, Paladini, Claudia, Paumard, Thibaut, Rousselet-Perraut, Karine, Perrin, Guy S., Pfuhl, Oliver, Rameau, Julien, Rodet, Laetitia, Rodriguez-Coira, Gustavo, Rousset, Gerard, Shangguan, Jinyi, Shimizu, Taro, Stadler, Julia, Straub, Odele, Straubmeier, Christian, Sturm, Eckhard, Stolker, Tomas, van Dishoeck, Ewine F., Vigan, Arthur, Vincent, Frederic, von Fellenberg, Sebastiano, Ward Duong, Kimb, Widmann, Felix, Wieprecht, Ekkehard, Wiezorrek, Erich, Woillez, Julien, Tuthill, Peter G., Mérand, Antoine, Sallum, Stephanie, Lacour, S., Wang, J. J., Nowak, Mathias, Pueyo, Laurent A., Eisenhauer, Frank, Lagrange, A.-M., Mollière, Paul, Abuter, Roberto, Amorin, António, Asensio-Torres, R., Baubock, Michi, Benisty, Myriam, Berger, Jean-Philippe, Beust, Hervé, Blunt, S., Boccaletti, Anthony, Bonnefoy, Mickaël, Bonnet, Henri, Brandner, Wolfgang, Cantalloube, Faustine, Caselli, Paola, Charnay, Benjamin, Chauvin, Gael, Choquet, Élodie, Christiaens, Valentin, Clénet, Yann, Cridland, Alex, de Zeeuw, Tim, Dembet, Roderick, Dexter, Jason, Drescher, Antonia, Duvert, Gilles, Gao, Feng, Garcia-Lopez, Rebeca, Gardner, Tyler, Gendron, Eric, Genzel, Reinhard, Gillessen, Stefan, Girard, Julien H., Haubois, Xavier, Heissel, Gernot, Henning, Thomas, Hinkley, Sasha, Hippler, Stefan, Horrobin, Matthew, Houlle, Matthis, Hubert, Zoltan, Jimenez Rosales, A, Jocou, Laurent, Kammerer, Jens, Keppler, Miriam, Kervella, Pierre, Kreidberg, Laura, Lapeyrere, Vincent, Le Bouquin, Jean-Baptiste, Léna, Pierre, Lutz, Dieter, Maire, Anne-Lise, Monnier, John, Mouillet, David, Muller, André, Nasedkin, E., Ott, Thomas, Otten, Gilles, Paladini, Claudia, Paumard, Thibaut, Rousselet-Perraut, Karine, Perrin, Guy S., Pfuhl, Oliver, Rameau, Julien, Rodet, Laetitia, Rodriguez-Coira, Gustavo, Rousset, Gerard, Shangguan, Jinyi, Shimizu, Taro, Stadler, Julia, Straub, Odele, Straubmeier, Christian, Sturm, Eckhard, Stolker, Tomas, van Dishoeck, Ewine F., Vigan, Arthur, Vincent, Frederic, von Fellenberg, Sebastiano, Ward Duong, Kimb, Widmann, Felix, Wieprecht, Ekkehard, Wiezorrek, Erich, and Woillez, Julien
Abstract: Combining adaptive optics and interferometric observations results in a considerable contrast gain compared to single-telescope, extreme AO systems. Taking advantage of this, the ExoGRAVITY project is a survey of known young giant exoplanets located in the range of 0.1” to 2” from their stars. The observations provide astrometric data of unprecedented accuracy, being crucial for refining the orbital parameters of planets and illuminating their dynamical histories. Furthermore, GRAVITY will measure non-Keplerian perturbations due to planet-planet interactions in multi-planet systems and measure dynamical masses. Over time, repetitive observations of the exoplanets at medium resolution (R = 500) will provide a catalogue of K-band spectra of unprecedented quality, for a number of exoplanets. The K-band has the unique properties that it contains many molecular signatures (CO, H₂O, CH₄, CO₂). This allows constraining precisely surface gravity, metallicity, and temperature, if used in conjunction with self-consistent models like Exo-REM. Further, we will use the parameter-retrieval algorithm petitRADTRANS to constrain the C/O ratio of the planets. Ultimately, we plan to produce the first C/O survey of exoplanets, kick-starting the difficult process of linking planetary formation with measured atomic abundances.
Published: 2020

28. Masses of the components of SB2 binaries observed with Gaia – V. Accurate SB2 orbits for 10 binaries and masses of the components of 5 binaries

Author: Halbwachs, Jean-Louis, Kiefer, Flavien, Lebreton, Yveline, Boffin, Henri, Arenou, Frédéric, Le Bouquin, Jean Baptiste, Famaey, Benoît, Pourbaix, Dimitri, Guillout, Patrick, Salomon, J.-B., Mazeh, Tsevi, Halbwachs, Jean-Louis, Kiefer, Flavien, Lebreton, Yveline, Boffin, Henri, Arenou, Frédéric, Le Bouquin, Jean Baptiste, Famaey, Benoît, Pourbaix, Dimitri, Guillout, Patrick, Salomon, J.-B., and Mazeh, Tsevi
Abstract: Double-lined spectroscopic binaries (SB2s) are one of the main sources of stellar masses, as additional observations are only needed to give the inclinations of the orbital planes in order to obtain the individual masses of the components. For this reason, we are observing a selection of SB2s using the SOPHIE spectrograph at the Haute-Provence observatory in order to precisely determine their orbital elements. Our objective is to finally obtain masses with an accuracy of the order of one per cent by combining our radial velocity (RV) measurements and the astrometric measurements that will come from the Gaia satellite. We present here the RVs and the re-determined orbits of 10 SB2s. In order to verify the masses, we will derive from Gaia, we obtained interferometric measurements of the ESO VLTI for one of these SB2s. Adding the interferometric or speckle measurements already published by us or by others for four other stars, we finally obtain the masses of the components of five binary stars, with masses ranging from 0.51 to 2.2 solar masses, including main-sequence dwarfs and some more evolved stars whose location in the HR diagram has been estimated., info:eu-repo/semantics/published
Published: 2020

29. Imagerie spectro-interférométrique du noyau de η Car avec l'instrument GRAVITY : images de la zone de collision de vent dans les raies Br γ et He I avec une résolution de la milli-seconde d'arc

Author: Sanchez-Bermudez, Joel, Weigelt, Gerd, Bestenlehner, Joachim M., Kervella, Pierre, Brandner, Wolfgang, Henning, Thomas, Müller, André, Perrin, Guy, Pott, Jorg-Uwe, Schöller, Markus, Van Boekel, Roy, Abuter, Roberto, Accardo, Matteo, Amorim, Antonio, Anugu, Narsireddy, Avila, Gerardo, Benisty, Myriam, Berger, Jean-Philippe, Blind, Nicolas, Bonnet, Henri, Bourget, Pierre, Brast, Roland, Buron, Alexander, Cantalloube, Faustine, Caratti O Garatti, Alessio, Cassaing, Frederic, Chapron, Frédéric, Choquet, Élodie, Clenet, Yann, Collin, Claude, Coude Du Foresto, Vincent, de Wit, Willem-Jan, De Zeeuw, Tim, Deen, Casey, Delplancke-Ströbele, Françoise, Dembet, Roderick, Derie, Frédéric, Dexter, Jason, Duvert, Gilles, Ebert, Monica, Eckart, Andreas, Eisenhauer, Frank, Esselborn, Michael, Fédou, Pierre, Garcia, Paulo J. V., Garcia-Dabo, Cesar Enrique, Garcia Lopez, Rebeca, Gao, Feng, Gendron, Eric, Genzel, Reinhard, Gillessen, Stefan, Haubois, Xavier, Haug, Marcus, Haussmann, Frank, Hippler, Stefan, Horrobin, Matthew, Huber, Armin, Huber, Zoltan, Hubin, Norbert, Hummel, Christian A., Jakob, Gerd, Jochum, Lieselotte, Jocou, Laurent, Karl, Martina, Kaufer, Andreas, Kellner, Stefan, Kendrew, Sarah, Kern, Lothar, Kiekebusch, Mario, Klein, Ralf, Kolb, Johann, Kulas, Martin, Lacour, Sylvestre, Lapeyrère, Vincent, Lazareff, Bernard, Le Bouquin, Jean-Baptiste, Léna, Pierre, Lenzen, Rainer, Lévêque, Samuel, Lippa, Magdalena, Magnard, Yves, Mehrgan, Leander, Mellein, Marcus, Mérand, Antoine, Moreno-Ventas, Javier, Moulin, Thibaut, Muller, Ewald, Muller, Friedrich, Neumann, Udo, Oberti, Sylvain, Ott, Thomas, Pallanca, Laurent, Panduro, Johana, Pasquini, Luca, Paumard, Thibaut, Percheron, Isabelle, Perraut, Karine, Petrucci, Pierre-Olivier, Pflüger, Andreas, Pfuhl, Oliver, Duc, Thanh Phan, Plewa, Philipp M., Popovic, Dan, Rabien, Sebastian, Ramirez, Andres, Ramos, Jose Ricardo, Rau, Christian, Riquelme, Miguel, Rodríguez-Coira, Gustavo, Rohloff, Ralf-Rainer, Rosales, Alejandra, Rousset, Gérard, Scheithauer, Silvia, Schuhler, Nicolas, Spyromilio, Jason, Straub, Odele, Straubmeier, Christian, Sturm, Eckhard, Suarez, Marco, Tristram, Konrad R. W., Ventura, Noel, Vincent, Frédéric, Waisberg, Idel, Wank, Imke, Widmann, Felix, Wieprecht, Ekkehard, Wiest, Michael, Wiezorrek, Erich, Wittkowski, Markus, Woillez, Julien, Wolff, Burkhard, Yazici, Senol, Ziegler, Denis, Zins, Gerard, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Max-Planck-Institut für Radioastronomie (MPIFR), University of Sheffield [Sheffield], 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), Universidad de Santiago de Chile [Santiago] (USACH), CENTRA Instituto Superior Tecnico, Universidade de Lisboa (ULISBOA), University of Exeter, 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), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Max Planck Institute for Extraterrestrial Physics (MPE), Dublin Institute for Advanced Studies (DIAS), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Leiden University, Physikalisches Institut [Köln], Universität zu Köln, Max Planck Institute for Radio Astronomy, Universidade do Porto [Porto], Instituto Superior Técnico, Technical University of Lisbon, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), European Space Agency (Baltimore) Space Telescope Science Institute (ESA), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon], ONERA-Université Paris Saclay (COmUE), Universidade do Porto, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: INSTRUMENTATION: HAUTE RESOLUTION ANGULAIRE, IMAGERIE STELLAIRE, BINARY STAR, MASS LOSS, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, HIGH ANGULAR RESOLUTION, INSTRUMENTATION: INTERFEROMETRES, ETOILE: PERTE DE MASSE, STAR IMAGING, INTERFEROMETER, ETOILES BINAIRES, MASSIVE STAR, ETOILES MASSIVES
Abstract: International audience; Context. η Car is one of the most intriguing luminous blue variables in the Galaxy. Observations and models of the X-ray, ultraviolet, optical, and infrared emission suggest a central binary in a highly eccentric orbit with a 5.54 yr period residing in its core. 2D and 3D radiative transfer and hydrodynamic simulations predict a primary with a dense and slow stellar wind that interacts with the faster and lower density wind of the secondary. The wind-wind collision scenario suggests that the secondary’s wind penetrates the primary’s wind creating a low-density cavity in it, with dense walls where the two winds interact. However, the morphology of the cavity and its physical properties are not yet fully constrained.Aims. We aim to trace the inner ∼5–50 au structure of η Car’s wind-wind interaction, as seen through Brγ and, for the first time, through the He I 2s-2p line.Methods. We have used spectro-interferometric observations with the K-band beam-combiner GRAVITY at the VLTI. The analyses of the data include (i) parametrical model-fitting to the interferometric observables, (ii) a CMFGEN model of the source’s spectrum, and (iii) interferometric image reconstruction.Results. Our geometrical modeling of the continuum data allows us to estimate its FWHM angular size close to 2 mas and an elongation ratio ϵ = 1.06 ± 0.05 over a PA = 130° ± 20°. Our CMFGEN modeling of the spectrum helped us to confirm that the role of the secondary should be taken into account to properly reproduce the observed Brγ and He I lines. Chromatic images across the Brγ line reveal a southeast arc-like feature, possibly associated to the hot post-shocked winds flowing along the cavity wall. The images of the He I 2s-2p line served to constrain the 20 mas (∼50 au) structure of the line-emitting region. The observed morphology of He I suggests that the secondary is responsible for the ionized material that produces the line profile. Both the Brγ and the He I 2s-2p maps are consistent with previous hydrodynamical models of the colliding wind scenario. Future dedicated simulations together with an extensive interferometric campaign are necessary to refine our constraints on the wind and stellar parameters of the binary, which finally will help us predict the evolutionary path of η Car.; Contexte : η Car est une des étoiles brillantes bleues variables les plus intrigante de notre galaxie. Les observations et les modèles des émissions X, UV et optique et IR suggèrent qu'une étoile binaire avec une orbite fortement excentrique de période 5,54 ans réside au centre de son coeur. Les simulations hydrodynamiques et de transfert radiatif 2D et 3D prédisent la présence d'une étoile primaire avec vent stellaire dense et lent, qui interagit avec le vent de densité moindre et plus rapide de l'étoile secondaire. Ce scénario de collision vent-vent suggère que le vent de l'étoile secondaire pénètre dans le vent de l'étoile primaire, créant dans ce dernier une cavité de faible densité, avec des murs denses où les deux vents interagissent. Cependant, la morphologie de cette cavité et ses propriétés physiques ne sont pas encore pleinement contraints.Objectifs. Nous visons à déterminer la structure interne de l’interaction vent-vent de Car dans une zone allant de 5 à 50 Unités Astronomiques, telle que vue à travers Br γ et, pour la première fois, à travers la transition 2s-2p de He I.Méthodes : Nous avons utilisé des observations spectro-interférométriques du combineur de faisceaux en bande K de GRAVITY au VLTI. Les analyses des données comprennent: (i) un ajustement de modèle paramétrique aux observables interférométriques, (ii) un modèle CMFGEN du spectre de la source, et (iii) des reconstructions d'image interférométriques.Résultats : Notre modélisation géométrique des données du continuum nous permet d'estimer sa taille angulaire FWHM proche de 2 mas et son coefficient d'allongement de 1,06 ± 0,05 sur un PA = 130° ± 20°. Notre modélisation CMFGEN du spectre nous a permis de confirmer que le rôle de l'étoile secondaire devrait être pris en compte pour reproduire correctement les émissions Br γ et He I observées. Les images spectrales dans la bande Br γ révèle une caractéristique semblable à un arc au sud-est, peut-être associé aux vents chauds post-choc circulant le long du mur de la cavité. Les images dans la bande He I 2s-2p ont servi à contraindre la structure de la région d'émission de la transition, avec une résolution de 20 millisecondes d'arc (50 UA). La morphologie observée de He I suggère que l'étoile secondaire est responsable de l'ionisationproduisant le profil de raie. Les deux images (en Br γ et He I 2s-2p) sont compatibles avec les modèles hydrodynamiques précédents du scénario de vent en collision. De futures simulations dédiées ainsi qu’une vaste campagne interférométrique sont nécessaires pour affiner nos contraintes sur le vent et les paramètres stellaires de la binaire, ce qui nous aidera enfin à prédire le chemin évolutif de η Car.
Published: 2018
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30. Constraining convection across the AGB with high-angular-resolution observations

Author: Paladini, Claudia, Baron, Fabien, Jorissen, Alain, Le Bouquin, Jean Baptiste, Freytag, Bernd, Van Eck, Sophie, Wittkowski, Markus, Hron, Josef, Chiavassa, Andréa, Berger, Jean-Philippe, Siopis, Christos, Mayer, Andreas, Sadowski, Gilles, Kravchenko, K., Shetye, Shreeya, Kerschbaum, Franz, Kluska, Jacques, Ramstedt, Sofia, Paladini, Claudia, Baron, Fabien, Jorissen, Alain, Le Bouquin, Jean Baptiste, Freytag, Bernd, Van Eck, Sophie, Wittkowski, Markus, Hron, Josef, Chiavassa, Andréa, Berger, Jean-Philippe, Siopis, Christos, Mayer, Andreas, Sadowski, Gilles, Kravchenko, K., Shetye, Shreeya, Kerschbaum, Franz, Kluska, Jacques, and Ramstedt, Sofia
Abstract: We present very detailed images of the photosphere of an AGB star obtained with the PIONIER instrument, installed at the Very Large Telescope Interferometer (VLTI). The images show a well defined stellar disc populated by a few convective patterns. Thanks to the high precision of the observations we are able to derive the contrast and granulation horizontal scale of the convective pattern for the first time in a direct way. Such quantities are then compared with scaling relations between granule size, effective temperature, and surface gravity that are predicted by simulations of stellar surface convection., SCOPUS: ar.k, info:eu-repo/semantics/published
Published: 2019

31. A discontinuity in theTeff–radius relation of M-dwarfs

Author: Rabus, Markus, primary, Lachaume, Régis, additional, Jordán, Andrés, additional, Brahm, Rafael, additional, Boyajian, Tabetha, additional, von Braun, Kaspar, additional, Espinoza, Néstor, additional, Berger, Jean-Philippe, additional, Le Bouquin, Jean-Baptiste, additional, and Absil, Olivier, additional
Published: 2019
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32. Multiple star systems in the Orion nebula

Author: Karl, Martina, Pfuhl, Oliver, Eisenhauer, Frank, Genzel, Reinhard, Grellmann, Rebekka, Habibi, Maryam, Abuter, Roberto, Accardo, Matteo, Amorim, Antonio, Anugu, Narsireddy, Avila, Gerardo, Benisty, Myriam, Berger, Jean-Philippe, Blind, Nicolas, Bonnet, Henri, Bourget, Pierre, Brandner, Wolfgang, Brast, Roland, Buron, Alexander, Garatti, Alessio Caratti O., Chapron, Frederic, Clenet, Yann, Collin, Claude, du Foresto, Vincent Coude, de Wit, Willem-Jan, de Zeeuw, Tim, Deen, Casey, Delplancke-Stroebele, Francoise, Dembet, Roderick, Derie, Frederic, Dexter, Jason, Duvert, Gilles, Ebert, Monica, Eckart, Andreas, Esselborn, Michael, Fedou, Pierre, Finger, Gert, Garcia, Paulo, Dabo, Cesar Enrique Garcia, Lopez, Rebeca Garcia, Gao, Feng, Gendron, Eric, Gillessen, Stefan, Gonte, Frederic, Gordo, Paulo, Groezinger, Ulrich, Guajardo, Patricia, Guieu, Sylvain, Haguenauer, Pierre, Hans, Oliver, Haubois, Xavier, Haug, Marcus, Haussmann, Frank, Henning, Thomas, Hippler, Stefan, Horrobin, Matthew, Huber, Armin, Hubert, Zoltan, Hubin, Norbert, Jakob, Gerd, Jochum, Lieselotte, Jocou, Laurent, Kaufer, Andreas, Kellner, Stefan, Kendrew, Sarah, Kern, Lothar, Kervella, Pierre, Kiekebusch, Mario, Klein, Ralf, Koehler, Rainer, Kolb, Johan, Kulas, Martin, Lacour, Sylvestre, Lapeyrere, Vincent, Lazareff, Bernard, Le Bouquin, Jean-Baptiste, Lena, Pierre, Lenzen, Rainer, Leveque, Samuel, Lin, Chien-Cheng, Lippa, Magdalena, Magnard, Yves, Mehrgan, Leander, Merand, Antoine, Moulin, Thibaut, Mueller, Eric, Mueller, Friedrich, Neumann, Udo, Oberti, Sylvain, Ott, Thomas, Pallanca, Laurent, Panduro, Johana, Pasquini, Luca, Paumard, Thibaut, Percheron, Isabelle, Perraut, Karine, Perrin, Guy, Pflueger, Andreas, Plewa, Philipp M., Popovic, Dan, Rabien, Sebastian, Ramirez, Andres, Ramos, Jose, Rau, Christian, Riquelme, Miguel, Rodriguez-Coira, Gustavo, Rohloff, Ralf-Rainer, Rosales, Alejandra, Rousset, Gerard, Sanchez-Bermudez, Joel, Scheithauer, Silvia, Schoeller, Markus, Schuhler, Nicolas, Spyromilio, Jason, Straub, Odele, Straubmeier, Christian, Sturm, Eckhard, Suarez, Marcos, Tristram, Konrad R. W., Ventura, Noel, Vincent, Frederic, Waisberg, Idel, Wank, Imke, Widmann, Felix, Wieprecht, Ekkehard, Wiest, Michael, Wiezorrek, Erich, Wittkowski, Markus, Woillez, Julien, Wolff, Burkhard, Yazici, Senol, Ziegler, Denis, Zins, Gerard, Karl, Martina, Pfuhl, Oliver, Eisenhauer, Frank, Genzel, Reinhard, Grellmann, Rebekka, Habibi, Maryam, Abuter, Roberto, Accardo, Matteo, Amorim, Antonio, Anugu, Narsireddy, Avila, Gerardo, Benisty, Myriam, Berger, Jean-Philippe, Blind, Nicolas, Bonnet, Henri, Bourget, Pierre, Brandner, Wolfgang, Brast, Roland, Buron, Alexander, Garatti, Alessio Caratti O., Chapron, Frederic, Clenet, Yann, Collin, Claude, du Foresto, Vincent Coude, de Wit, Willem-Jan, de Zeeuw, Tim, Deen, Casey, Delplancke-Stroebele, Francoise, Dembet, Roderick, Derie, Frederic, Dexter, Jason, Duvert, Gilles, Ebert, Monica, Eckart, Andreas, Esselborn, Michael, Fedou, Pierre, Finger, Gert, Garcia, Paulo, Dabo, Cesar Enrique Garcia, Lopez, Rebeca Garcia, Gao, Feng, Gendron, Eric, Gillessen, Stefan, Gonte, Frederic, Gordo, Paulo, Groezinger, Ulrich, Guajardo, Patricia, Guieu, Sylvain, Haguenauer, Pierre, Hans, Oliver, Haubois, Xavier, Haug, Marcus, Haussmann, Frank, Henning, Thomas, Hippler, Stefan, Horrobin, Matthew, Huber, Armin, Hubert, Zoltan, Hubin, Norbert, Jakob, Gerd, Jochum, Lieselotte, Jocou, Laurent, Kaufer, Andreas, Kellner, Stefan, Kendrew, Sarah, Kern, Lothar, Kervella, Pierre, Kiekebusch, Mario, Klein, Ralf, Koehler, Rainer, Kolb, Johan, Kulas, Martin, Lacour, Sylvestre, Lapeyrere, Vincent, Lazareff, Bernard, Le Bouquin, Jean-Baptiste, Lena, Pierre, Lenzen, Rainer, Leveque, Samuel, Lin, Chien-Cheng, Lippa, Magdalena, Magnard, Yves, Mehrgan, Leander, Merand, Antoine, Moulin, Thibaut, Mueller, Eric, Mueller, Friedrich, Neumann, Udo, Oberti, Sylvain, Ott, Thomas, Pallanca, Laurent, Panduro, Johana, Pasquini, Luca, Paumard, Thibaut, Percheron, Isabelle, Perraut, Karine, Perrin, Guy, Pflueger, Andreas, Plewa, Philipp M., Popovic, Dan, Rabien, Sebastian, Ramirez, Andres, Ramos, Jose, Rau, Christian, Riquelme, Miguel, Rodriguez-Coira, Gustavo, Rohloff, Ralf-Rainer, Rosales, Alejandra, Rousset, Gerard, Sanchez-Bermudez, Joel, Scheithauer, Silvia, Schoeller, Markus, Schuhler, Nicolas, Spyromilio, Jason, Straub, Odele, Straubmeier, Christian, Sturm, Eckhard, Suarez, Marcos, Tristram, Konrad R. W., Ventura, Noel, Vincent, Frederic, Waisberg, Idel, Wank, Imke, Widmann, Felix, Wieprecht, Ekkehard, Wiest, Michael, Wiezorrek, Erich, Wittkowski, Markus, Woillez, Julien, Wolff, Burkhard, Yazici, Senol, Ziegler, Denis, and Zins, Gerard
Abstract: This work presents an interferometric study of the massive-binary fraction in the Orion Trapezium cluster with the recently comissioned GRAVITY instrument. We observed a total of 16 stars of mainly OB spectral type. We find three previously unknown companions for theta(1) Ori B, theta(2) Ori B, and theta(2) Ori C. We determined a separation for the previously suspected companion of NU Ori. We confirm four companions for theta(1) Ori A, theta(1) Ori C, theta(1) Ori D, and theta(2) Ori A, all with substantially improved astrometry and photometric mass estimates. We refined the orbit of the eccentric high-mass binary theta(1) Ori C and we are able to derive a new orbit for theta(1) Ori D. We find a system mass of 21.7 M-circle dot and a period of 53 days. Together with other previously detected companions seen in spectroscopy or direct imaging, eleven of the 16 high-mass stars are multiple systems. We obtain a total number of 22 companions with separations up to 600 AU. The companion fraction of the early B and O stars in our sample is about two, significantly higher than in earlier studies of mostly OB associations. The separation distribution hints toward a bimodality. Such a bimodality has been previously found in A stars, but rarely in OB binaries, which up to this point have been assumed to be mostly compact with a tail of wider companions. We also do not find a substantial population of equal-mass binaries. The observed distribution of mass ratios declines steeply with mass, and like the direct star counts, indicates that our companions follow a standard power law initial mass function. Again, this is in contrast to earlier findings of flat mass ratio distributions in OB associations. We excluded collision as a dominant formation mechanism but find no clear preference for core accretion or competitive accretion.
Published: 2018

33. Constraining Convection in Evolved Stars with the VLTI

Author: Paladini, Claudia, Baron, Fabien, Jorissen, Alain, Le Bouquin, Jean Baptiste, Freytag, Bernd, Van Eck, Sophie, Wittkowski, Markus, Hron, Josef, Chiavassa, Andréa, Berger, Jean-Philippe, Siopis, Christos, Mayer, Andreas, Sadowski, Gilles, Kravchenko, Kateryna, Shetye, Shreeya, Kerschbaum, Franz, Kluska, Jacques, Ramstedt, Sofia, Paladini, Claudia, Baron, Fabien, Jorissen, Alain, Le Bouquin, Jean Baptiste, Freytag, Bernd, Van Eck, Sophie, Wittkowski, Markus, Hron, Josef, Chiavassa, Andréa, Berger, Jean-Philippe, Siopis, Christos, Mayer, Andreas, Sadowski, Gilles, Kravchenko, Kateryna, Shetye, Shreeya, Kerschbaum, Franz, Kluska, Jacques, and Ramstedt, Sofia
Abstract: info:eu-repo/semantics/published
Published: 2018

34. First light for GRAVITY: Phase referencing optical interferometry for the Very Large Telescope Interferometer

Author: Abuter, Roberto, Accardo, Matteo, Antonio, Amorim, Narsireddy, Anugu, Avila, Gerardo, Azouaoui, N., Benisty, Myriam, Berger, Jean-Philippe, Blind, Nicolas, Bonnet, Henri, Bourget, Pierre, Brandner, Wolfgang, Brast, Roland, Buron, Alexander, Burtscher, L., Cassaing, Frederic, Chapron, Frédéric, Choquet, Elodie, Clénet, Yann, Collin, Claude, Coudé du Forestol, Vincent, de Wit, Willem-Jan, De Zeeuw, Tim, Casey, Deen, Delplancke-Ströbele, Françoise, Dembet, Roderick, Derie, Frédéric, Dexter, Jason, Duvert, Gilles, Ebert, Monica, Eckart, Andreas, Eisenhauer, Frank, Michael, Esselborn, Fédou, Pierre, Finger, Gert, Garcia, Paulo, Garcia Dabo, Cesar Enrique, Garcia Lopez, Rebeca, Gendron, Eric, Genzel, Reinhard, Gillessen, Stefan, Conté, Frédéric, Gordo, Paulo, Grould, Marion, Groözinger, Ulrich, Guieu, Sylvain, Haguenauer, Pierre, Hans, Olivier, Haubois, Xavier, Haug, Marcus, Haussmann, Frank, Henning, Thomas, Hippler, Stefan, Horrobin, Matthew, Huber, Armin, Hubert, Zoltan, Hubin, Norbert, Hummel, Christian, Jakob, Gerd, Janssen, A., Jochum, Lieselotte, Jocou, Laurent, Kaufer, Andreas, Kellner, Stefan, Kendrew, Sarah, Kern, Lothar, Kervella, Pierre, Kiekebusch, Mario, Klein, Ralf, Kok, Y., Kolb, Johan, Kulas, Martin, Lacour, Sylvestre, Lapeyrère, Vincent, Lazareff, Bernard, Le Bouquin, Jean-Baptiste, Léna, Pierre, Lenzen, Rainer, Levêque, Samuel, Lippa, Magdalena, Magnard, Yves, Mehrgan, Leander, Mellein, Marcus, Merand, Antoine, Moreno-Ventas, Javier, Moulin, Thibaut, Müller, Eric, Müller, Fredrich, Neumann, Udo, Oberti, Sylvain, Ott, Thomas, Pallanca, Laurent, Panduro, Johana, Pasquini, Luca, Paumard, Thibaut, Percheron, Isabelle, Perraut, Karine, Perrin, Guy, Pflüger, Andreas, Pfuhl, Olivier, Duc, Thanh Phan, Plewa, Philipp, Popovic, Dan, Rabien, Sebastian, Ramirez, Andres, Ramos, Jose, Rau, Christian, Riquelme, Miguel, Rohloff, Ralf-Rainer, Rousset, Gérard, Sanchez-Bermudez, Joel, Scheithauer, Sylvia, Schöller, Marcus, Schuhler, Nicolas, Spyromilio, Jason, Straubmeier, Christian, Sturm, Eckhard, Suarez, Marco, Tristram, Konrad, Ventura, Noel, Vincent, Frédéric, Waisberg, Idel, Wank, Imke, Weber, J., Wieprecht, Ekkehard, Wiest, Michael, Wiezorrek, Erich, Wittkowski, Markus, Woillez, Julien, Wolff, Burkhard, Yazici, Senol, Ziegler, Denis, Zins, Gérard, Amorim, A., Anugu, N., Ávila, G., Clenet, Y., Coudé Du Foresto, V., de Zeeuw, P., Deen, C., Esselborn, M., Dabo, C, Gonte, F., Grözinger, U., Henning, Th, Le Bouquin, J.-B, Lèna, P., Lévêque, S., Mérand, A., Muller, E., Muller, F., Phan Duc, T., Ramírez, A., Garcia Dabo, E., Henning, Th., Le Bouquin, B., Plewa, M., European Southern Observatory (ESO), CENTRA, Universidade de Lisboa, CENTRA, Universidade do Porto, 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), 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), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Max Planck Institute for Extraterrestrial Physics (MPE), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], ONERA - The French Aerospace Lab [Châtillon], ONERA, Physikalisches Institut [Köln], Universität zu Köln, Max Planck Institute for Radio Astronomy, Department of Physics [Berkeley], University of California [Berkeley], University of California-University of California, European Space Agency (ESA), European Southern Observatory [Santiago] (ESO), Institute Patology and Imunology Molecular, Fac Ciencias, Universidade do Porto [Porto], Brain Mind Institute (BMI - EPFL), Ecole Polytechnique Fédérale de Lausanne (EPFL), Technische Universität Dresden (TUD), Departamento de Control Automático (CINVESTAV-IPN), Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN), Universidade do Porto, 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 national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ONERA-Université Paris Saclay (COmUE), GRAVITY Collaboration, European Southern Observatory ( ESO ), 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 ), 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 national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -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 ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire Astronomique de l'Université de Genève ( ObsGE ), Université de Genève ( UNIGE ), Max-Planck-Institut für Astronomie ( MPIA ), Max Planck Institute for Extraterrestrial Physics ( MPE ), ONERA - The French Aerospace Lab ( Chatillon ), Max Planck Institute for Radio Astronomy, Bonn, European Space Agency ( ESA ), Universidad de Santiago de Chile [Santiago] ( USACH ), European Southern Observatory [Santiago] ( ESO ), University of Porto, Center for Brain Simulation, Ecole Polytechnique Fédérale de Lausanne, Technische Universität Dresden ( TUD ), Departamento de Control Automático ( CINVESTAV-IPN ), Center for Research and Advanced Studies of the National Polytechnic Institute ( CINVESTAV-IPN ), Universidade do Porto = University of Porto, Université de Genève = University of Geneva (UNIGE), Universiteit Leiden, Universität zu Köln = University of Cologne, University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: [ SPI.SIGNAL ] Engineering Sciences [physics]/Signal and Image processing, Astrophysics, ÉTOILE DOUBLE, OPTIQUE ADAPTATIVE, 01 natural sciences, law.invention, law, Astrophysics::Solar and Stellar Astrophysics, INSTRUMENTATION OPTIQUE, INSTRUMENTATION, instrumentation: interferometers, 010303 astronomy & astrophysics, Physics, Galaxy: center, Galactic Center, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], [ PHYS.PHYS.PHYS-SPACE-PH ] Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], quasars: emission lines, Interferometry, EMISSION LINE, Closure phase, binaries: symbiotic, Astrophysics::Earth and Planetary Astrophysics, [ SPI.OPTI ] Engineering Sciences [physics]/Optics / Photonic, Astrophysics - Instrumentation and Methods for Astrophysics, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, CENTER, INTERFEROMETRIE GRANDE BASE, FOS: Physical sciences, stars: pre-main sequence, instrumentation: adaptive optics, QUASAR, 010309 optics, Telescope, 0103 physical sciences, Angular resolution, INTERFEROMETERS, Instrumentation and Methods for Astrophysics (astro-ph.IM), CENTRE GALACTIQUE, Astrophysics::Galaxy Astrophysics, ADAPTIVE OPTICS, Very Large Telescope, Astronomy and Astrophysics, First light, GALAXY, Space and Planetary Science, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: GRAVITY is a new instrument to coherently combine the light of the European Southern Observatory Very Large Telescope Interferometer to form a telescope with an equivalent 130 m diameter angular resolution and a collecting area of 200 m$^2$. The instrument comprises fiber fed integrated optics beam combination, high resolution spectroscopy, built-in beam analysis and control, near-infrared wavefront sensing, phase-tracking, dual beam operation and laser metrology [...]. This article gives an overview of GRAVITY and reports on the performance and the first astronomical observations during commissioning in 2015/16. We demonstrate phase tracking on stars as faint as m$_K$ ~ 10 mag, phase-referenced interferometry of objects fainter than m$_K$ ~ 15 mag with a limiting magnitude of m$_K$ ~ 17 mag, minute long coherent integrations, a visibility accuracy of better than 0.25 %, and spectro-differential phase and closure phase accuracy better than 0.5{\deg}, corresponding to a differential astrometric precision of better than 10 microarcseconds ({\mu}as). The dual-beam astrometry, measuring the phase difference of two objects with laser metrology, is still under commissioning. First observations show residuals as low as 50 {\mu}as when following objects over several months. We illustrate the instrument performance with the observations of archetypical objects for the different instrument modes. Examples include the Galactic Center supermassive black hole and its fast orbiting star S2 for phase referenced dual beam observations and infrared wavefront sensing, the High Mass X-Ray Binary BP Cru and the Active Galactic Nucleus of PDS 456 for few {\mu}as spectro-differential astrometry, the T Tauri star S CrA for a spectro-differential visibility analysis, {\xi} Tel and 24 Cap for high accuracy visibility observations, and {\eta} Car for interferometric imaging with GRAVITY., Comment: Accepted for publication in A&A, 23 pages, 23 figures, corresponding author: F. Eisenhauer
Published: 2017
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35. A discontinuity in the Teff–radius relation of M-dwarfs.

Author: Rabus, Markus, Lachaume, Régis, Jordán, Andrés, Brahm, Rafael, Boyajian, Tabetha, von Braun, Kaspar, Espinoza, Néstor, Berger, Jean-Philippe, Le Bouquin, Jean-Baptiste, and Absil, Olivier
Subjects: RADIUS (Geometry), STELLAR atmospheres, COOL stars (Astronomy)
Abstract: We report on 13 new high-precision measurements of stellar diameters for low-mass dwarfs obtained by means of near-infrared long-baseline interferometry with PIONIER at the Very Large Telescope Interferometer. Together with accurate parallaxes from Gaia DR2, these measurements provide precise estimates for their linear radii, effective temperatures, masses, and luminosities. This allows us to refine the effective temperature scale, in particular towards the coolest M-dwarfs. We measure for late-type stars with enhanced metallicity slightly inflated radii, whereas for stars with decreased metallicity we measure smaller radii. We further show that Gaia DR2 effective temperatures for M-dwarfs are underestimated by ∼8.2 per cent and give an empirical MG – T eff relation that is better suited for M-dwarfs with T eff between 2600 and 4000 K. Most importantly, we are able to observationally identify a discontinuity in the T eff–radius plane, which is likely due to the transition from partially convective M-dwarfs to the fully convective regime. We found this transition to happen between 3200 and 3340 K, or equivalently for stars with masses |${\approx } 0.23\, \mathrm{M}_{\odot }$|⁠. We find that in this transition region the stellar radii are in the range from 0.18 to 0.42 R |$\odot$| for similar stellar effective temperatures. [ABSTRACT FROM AUTHOR]
Published: 2019
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36. Large granulation cells on the surface of the giant star pi 1 Gruis.

Author: Paladini, Claudia, Baron, Fabien, Jorissen, Alain, Le Bouquin, Jean Baptiste, Freytag, Bernd, Van Eck, Sophie, Wittkowski, Markus, Hron, Josef, Chiavassa, Andréa, Berger, Jean-Philippe, Siopis, Christos, Mayer, A., Sadowski, Gilles, Kravchenko, Kateryna, Shetye, Shreeya, Kerschbaum, Franz, Kluska, Jacques, Ramstedt, Sofia, Paladini, Claudia, Baron, Fabien, Jorissen, Alain, Le Bouquin, Jean Baptiste, Freytag, Bernd, Van Eck, Sophie, Wittkowski, Markus, Hron, Josef, Chiavassa, Andréa, Berger, Jean-Philippe, Siopis, Christos, Mayer, A., Sadowski, Gilles, Kravchenko, Kateryna, Shetye, Shreeya, Kerschbaum, Franz, Kluska, Jacques, and Ramstedt, Sofia
Abstract: Convection plays a major part in many astrophysical processes, including energy transport, pulsation, dynamos and winds on evolved stars, in dust clouds and on brown dwarfs. Most of our knowledge about stellar convection has come from studying the Sun: about two million convective cells with typical sizes of around 2,000 kilometres across are present on the surface of the Sun-a phenomenon known as granulation. But on the surfaces of giant and supergiant stars there should be only a few large (several tens of thousands of times larger than those on the Sun) convective cells, owing to low surface gravity. Deriving the characteristic properties of convection (such as granule size and contrast) for the most evolved giant and supergiant stars is challenging because their photospheres are obscured by dust, which partially masks the convective patterns. These properties can be inferred from geometric model fitting, but this indirect method does not provide information about the physical origin of the convective cells. Here we report interferometric images of the surface of the evolved giant star π1 Gruis, of spectral type S5,7. Our images show a nearly circular, dust-free atmosphere, which is very compact and only weakly affected by molecular opacity. We find that the stellar surface has a complex convective pattern with an average intensity contrast of 12 per cent, which increases towards shorter wavelengths. We derive a characteristic horizontal granule size of about 1.2 × 1011 metres, which corresponds to 27 per cent of the diameter of the star. Our measurements fall along the scaling relations between granule size, effective temperature and surface gravity that are predicted by simulations of stellar surface convection., SCOPUS: ar.j, info:eu-repo/semantics/published
Published: 2017

37. Aperture synthesis imaging of the carbon AGB star R Sculptoris: Detection of a complex structure and a dominating spot on the stellar disk

Author: Wittkowski, Markus, De Gregorio-Monsalvo, Itziar, Eriksson, Kjell, Hron, Josef, Humphreys, Elizabeth M L, Lindqvist, Michael, Maercker, Matthias, Mohamed, Shazrene, Olofsson, Hans, Ramstedt, Sofia, Weigelt, Gerd, Hofmann, Karl Heinz, Höfner, Susanne, Le Bouquin, Jean Baptiste, Nowotny, Walter, Paladini, Claudia, Young, John, Berger, Jean-Philippe, Brunner, Matthias, Wittkowski, Markus, De Gregorio-Monsalvo, Itziar, Eriksson, Kjell, Hron, Josef, Humphreys, Elizabeth M L, Lindqvist, Michael, Maercker, Matthias, Mohamed, Shazrene, Olofsson, Hans, Ramstedt, Sofia, Weigelt, Gerd, Hofmann, Karl Heinz, Höfner, Susanne, Le Bouquin, Jean Baptiste, Nowotny, Walter, Paladini, Claudia, Young, John, Berger, Jean-Philippe, and Brunner, Matthias
Abstract: Aims. We present near-infrared interferometry of the carbon-rich asymptotic giant branch (AGB) star R Sculptoris (R Scl). Methods. We employ medium spectral resolution K-band interferometry obtained with the instrument AMBER at the Very Large Telescope Interferometer (VLTI) and H-band low spectral resolution interferometric imaging observations obtained with the VLTI instrument PIONIER. We compare our data to a recent grid of dynamic atmosphere and wind models. We compare derived fundamental parameters to stellar evolution models. Results. The visibility data indicate a broadly circular resolved stellar disk with a complex substructure. The observed AMBER squared visibility values show drops at the positions of CO and CN bands, indicating that these lines form in extended layers above the photosphere. The AMBER visibility values are best fit by a model without a wind. The PIONIER data are consistent with the same model. We obtain a Rosseland angular diameter of 8.9 ± 0.3 mas, corresponding to a Rosseland radius of 355 ± 55 R⊙, an effective temperature of 2640 ± 80 K, and a luminosity of log L/L⊙ = 3.74 ± 0.18. These parameters match evolutionary tracks of initial mass 1.5 ± 0.5 M⊙ and current mass 1.3 ± 0.7 M⊙. The reconstructed PIONIER images exhibit a complex structure within the stellar disk including a dominant bright spot located at the western part of the stellar disk. The spot has an H-band peak intensity of 40% to 60% above the average intensity of the limb-darkening-corrected stellar disk. The contrast between the minimum and maximum intensity on the stellar disk is about 1:2.5. Conclusions. Our observations are broadly consistent with predictions by dynamic atmosphere and wind models, although models with wind appear to have a circumstellar envelope that is too extended compared to our observations. The detected complex structure within the stellar disk is most likely caused by giant convection cells, resulting in large-scale shock fronts, and their effect, SCOPUS: ar.j, info:eu-repo/semantics/published
Published: 2017

38. The programme ''accurate masses for SB2 components'

Author: Halbwachs, Jean-Louis, Arenou, Frédéric, Boffin, Henri, Famaey, Benoît, Jorissen, Alain, Kiefer, F., Le Bouquin, Jean Baptiste, Pourbaix, Dimitri, Guillout, Patrick, Ibata, Rodrigo, Lebreton, Yveline, Mazeh, Tsevi, Nebot Gómez-Morán, A., Tal-Or, Lev, Halbwachs, Jean-Louis, Arenou, Frédéric, Boffin, Henri, Famaey, Benoît, Jorissen, Alain, Kiefer, F., Le Bouquin, Jean Baptiste, Pourbaix, Dimitri, Guillout, Patrick, Ibata, Rodrigo, Lebreton, Yveline, Mazeh, Tsevi, Nebot Gómez-Morán, A., and Tal-Or, Lev
Abstract: info:eu-repo/semantics/published
Published: 2017

39. Luminous blue variables: An imaging perspective on their binarity and near environment

Author: Martayan, Christophe, primary, Lobel, Alex, additional, Baade, Dietrich, additional, Mehner, Andrea, additional, Rivinius, Thomas, additional, Boffin, Henri M. J., additional, Girard, Julien, additional, Mawet, Dimitri, additional, Montagnier, Guillaume, additional, Blomme, Ronny, additional, Kervella, Pierre, additional, Sana, Hugues, additional, Štefl, Stanislav, additional, Zorec, Juan, additional, Lacour, Sylvestre, additional, Le Bouquin, Jean-Baptiste, additional, Martins, Fabrice, additional, Mérand, Antoine, additional, Patru, Fabien, additional, Selman, Fernando, additional, and Frémat, Yves, additional
Published: 2016
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40. Aperture synthesis imaging, application to Chemically Peculiar stars

Author: Le Bouquin, Jean-Baptiste, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Joseph-Fourier - Grenoble I, Perraut Karine(karine.perraut@obs.ujf-grenoble.fr), and Le Bouquin, Jean-Baptiste
Subjects: [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], integrated optics, interferometrie optique, chemically peculiar stars, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], optical interferometry, etoiles chimiquement particulieres, optique integree
Abstract: The on-going revolution due to high angular resolution observations promises to unlock tightly-kept secrets of stellar astrophysics. Complementary polarization diagnostics at high angular resolution will open new opportunities by resolving local polarized features always averaged, and thus lost, in classical spectro-polarimetry. After describing the issue of chemically peculiar stars (Ap) observations, I develop a numerical tool with which I show how interferometric measurements improve the reconstruction of the abundance map and magnetic topology. Observations at GI2T validate this spectro-polarimetric mode on an interferometer. Nevertheless, a first attempt to obtain data on Ap stars failed due to technical and meteorological reasons.Aperture synthesis imaging is the natural extension of this differential methods. Yet, its application to Ap stars requires simultaneously high (u,v) coverage, high spectral resolution and eventually polarisation analysis. In the context of a spectro-imaging interferometer with a large number of telescopes (VITRUV proposition for the VLTI), I confirm the interest of planar optics by mean of VLTI observations. I study different combination concepts and compare there performances. Finally, I start the study of instrumental polarisation and asses the specifications for a polarimetric mode at VLTI., L'avènement des techniques de haute resolution angulaire revolutionne notre connaissance des objets stellaires. En particulier, les diagnostiques de polarisation couples l'interferometrie ouvrent de nouvelles perspectives, en resolvant les structures polarises generalement moyennees sur la surface et donc perdues en spectro-polarimetrie classique. Apres avoir rappele les enjeux de l'observation des etoiles chimiquement particulieres (Ap), je developpe un outil de simulation numerique, avec lequel je montre que l'introduction des mesures interferometriques marginalement rsolues ameliore la reconstruction des cartes d'abondance et de topologie magnetique. Des observations au GI2T valident ce mode spectro-polarimtrique sur un interferometre. Neanmoins, des problemes techniques m'ont empeche d'obtenir des donnees de qualite suffisante pour une exploitation sur les etoiles Ap.L'imagerie par synthese d'ouverture est le prolongement naturel de ces methodes differentielles. Cependant son application aux toiles Ap necessite simultanment une forte couverture du plan (u,v), une haute resolution spectrale et eventuellement une analyse de la polarisation. Dans ce contexte d'un interferometre spectro-imageur a grand nombre de telescopes (proposition VITRUV), je confirme l'interet de l'optique planaire par des observations au VLTI. J'etudie differents concepts de recombinaison et compare leurs performances. Enfin, j'ebauche l'analyse de la polarisation instrumentale et en deduit les specifications pour un mode polarimetrique au VLTI.
Published: 2005

41. Accurate stellar masses for SB2 components: Interferometric observations for Gaia validation

Author: Halbwachs, Jean-Louis, Boffin, Henri, Le Bouquin, Jean Baptiste, Famaey, Benoît, Salomon, J.-B., Arenou, Frédéric, Pourbaix, Dimitri, Anthonioz, Fabien, Grellmann, Rebekka, Guieu, Sylvain, Guillout, Patrick, Jorissen, Alain, Kiefer, F., Lebreton, Yveline, Mazeh, Tsevi, Nebot Gómez-Morán, A., Sana, Hugues, Tal-Or, Lev, Halbwachs, Jean-Louis, Boffin, Henri, Le Bouquin, Jean Baptiste, Famaey, Benoît, Salomon, J.-B., Arenou, Frédéric, Pourbaix, Dimitri, Anthonioz, Fabien, Grellmann, Rebekka, Guieu, Sylvain, Guillout, Patrick, Jorissen, Alain, Kiefer, F., Lebreton, Yveline, Mazeh, Tsevi, Nebot Gómez-Morán, A., Sana, Hugues, and Tal-Or, Lev
Abstract: info:eu-repo/semantics/published
Published: 2015

42. X-shooter, NACO, and AMBER observations of the LBV Pistol Star \footnote{Based on ESO runs 85.D-0182A, 085.D-0625AC}

Author: Martayan, Christophe, Blomme, Ronny, Le Bouquin, Jean-Baptiste, Merand, Antoine, Montagnier, Guillaume, Selman, Fernando, Girard, Julien, Fox, Andrew, Baade, Dietrich, Fremat, Yves, Lobel, Alex, Martins, Fabrice, Patru, Fabien, Rivinius, Thomas, Sana, Hugues, Stefl, Stan, Zorec, Jean, Semaan, Thierry, European Southern Observatory (ESO), 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), Royal Observatory of Belgium [Brussels] (ROB), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Groupe de Recherche en Astronomie et Astrophysique du Languedoc (GRAAL), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Amsterdam [Amsterdam] (UvA), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Astrophysics - Solar and Stellar Astrophysics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract: We present multi-instruments and multi-wavelengths observations of the famous LBV star Pistol Star. These observations are part of a larger program about early O stars at different metallicities. The Pistol star has been claimed as the most massive star known, with 250 solar masses. We present the preliminary results based on X-Shooter spectra, as well as the observations performed with the VLTI-AMBER and the VLT-NACO adaptive optics. The X-shooter spectrograph allows to obtain simultaneously a spectrum from the UV to the K-band with a resolving power of $\sim$15000. The preliminary results obtained indicate that Pistol Star has similar properties of Eta Car, including shells of matter, but also the binarity. Other objects of the program, here briefly presented, were selected for their particular nature: early O stars with mass discrepancies between stellar evolution models and observations, discrepancies with the wind momentum luminosity relation., Poster at the 39th LIAC, submitted version of the proceedings
Published: 2010

43. A PIONIER View on Mass-transferring Red Giants

Author: Boffin, Henri, Blind, N., Hillen, M., Berger, Jean-Philippe, Jorissen, Alain, Le Bouquin, Jean Baptiste, Boffin, Henri, Blind, N., Hillen, M., Berger, Jean-Philippe, Jorissen, Alain, and Le Bouquin, Jean Baptiste
Abstract: info:eu-repo/semantics/published
Published: 2014

44. Roche-lobe filling factor of mass-transferring red giants: the PIONIER view

Author: Boffin, Henri, Hillen, M., Berger, Jean-Philippe, Jorissen, Alain, Blind, N., Le Bouquin, Jean Baptiste, Mikolajewska, Joanna, Lazareff, B., Boffin, Henri, Hillen, M., Berger, Jean-Philippe, Jorissen, Alain, Blind, N., Le Bouquin, Jean Baptiste, Mikolajewska, Joanna, and Lazareff, B.
Abstract: Using the PIONIER visitor instrument that combines the light of the four Auxiliary Telescopes of ESO's Very Large Telescope Interferometer, we precisely measure the diameters of several symbiotic and related stars: HD 352, HD 190658, V1261 Ori, ER Del, FG Ser, and AG Peg. These diameters - in the range of 0.6-2.3 milli-arcsec - are used to assess the filling factor of the Roche lobe of the mass-losing giants and provide indications on the nature of the ongoing mass transfer. We also provide the first spectroscopic orbit of ER Del, based on CORAVEL and HERMES/Mercator observations. The system is found to have an eccentric orbit with a period of 5.7 years. In the case of the symbiotic star FG Ser, we find that the diameter changes by 13% over the course of 41 days, while the observations of HD 352 are indicative of an elongation. Both these stars are found to have a Roche filling factor close to 1, as is most likely the case for HD 190658 as well, while the three other stars have factors below 0.5-0.6. Our observations reveal the power of interferometry for the study of interacting binary stars; the main limitation in our conclusions is the poorly known distances of the objects. © ESO, 2014., SCOPUS: ar.j, info:eu-repo/semantics/published
Published: 2014

45. THE THREE-BODY SYSTEM δ CIRCINI

Author: Mayer, Pavel, primary, Harmanec, Petr, additional, Sana, Hugues, additional, and Le Bouquin, Jean-Baptiste, additional
Published: 2014
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46. Imaging the heart of astrophysical objects with optical long-baseline interferometry

Author: Berger, Jean-Philippe, Malbet, Fabien, Baron, Fabien, Chiavassa, Andréa, Duvert, Gilles, Elitzur, Moshe, Freytag, Bernd, Gueth, Frédéric, Hönig, Sebastian S.F., Hron, Josef, Jang-Condell, Hannah, Le Bouquin, Jean Baptiste, Monin, Jean Louis, Monnier, John J.D., Perrin, Guillaume G.S., Plez, Bertrand, Ratzka, Thorsten, Renard, Stéphanie, Stefl, Stanislav, Thiébaut, Éric, Tristram, Konrad K.R.W., Verhoelst, Tijl, Wolf, Sebastian, Young, John, Berger, Jean-Philippe, Malbet, Fabien, Baron, Fabien, Chiavassa, Andréa, Duvert, Gilles, Elitzur, Moshe, Freytag, Bernd, Gueth, Frédéric, Hönig, Sebastian S.F., Hron, Josef, Jang-Condell, Hannah, Le Bouquin, Jean Baptiste, Monin, Jean Louis, Monnier, John J.D., Perrin, Guillaume G.S., Plez, Bertrand, Ratzka, Thorsten, Renard, Stéphanie, Stefl, Stanislav, Thiébaut, Éric, Tristram, Konrad K.R.W., Verhoelst, Tijl, Wolf, Sebastian, and Young, John
Abstract: The number of publications of aperture-synthesis images based on optical long-baseline interferometry measurements has recently increased due to easier access to visible and infrared interferometers. The interferometry technique has now reached a technical maturity level that opens new avenues for numerous astrophysi-cal topics requiring milli-arcsecond model-independent imaging. In writing this paper our motivation was twofold: (1) review and publicize emblematic excerpts of the impressive corpus accumulated in the field of optical interferometry image reconstruction; (2) discuss future prospects for this technique by selecting four representative astrophysical science cases in order to review the potential benefits of using optical long-baseline interferometers. For this second goal we have simulated interferometric data from those selected astrophysical environments and used state-of-the-art codes to provide the reconstructed images that are reachable with current or soon-to-be facilities. The imagereconstruction process was “blind” in the sense that reconstructors had no knowledge of the input brightness distributions. We discuss the impact of optical interferometry in those four astrophysical fields. We show that image-reconstruction software successfully provides accurate morphological information on a variety of astrophysical topics and review the current strengths and weaknesses of such reconstructions. We investigate how to improve image reconstruction and the quality of the image possibly by upgrading the current facilities. We finally argue that optical interferometers and their corresponding instrumentation, existing or to come, with six to ten telescopes, should be well suited to provide images of complex sceneries., SCOPUS: re.j, info:eu-repo/semantics/published
Published: 2012

47. Milli-arcsecond Astrophysics with VSI, the VLTI Spectro-imager in the ELT Era

Author: Malbet, F., Buscher, D., Weigelt, G., Garcia, P., Gai, M., Lorenzetti, D, Surdej, J., Hron, Josef, Neuhäuser, R., Kern, P., Jocou, L., Berger, Jean-Philippe, Absil, O., Beckmann, U., Corcione, L., Duvert, G., Filho, M., Labeye, P., Le Coarer, E., Li Causi, G., Lima, J., Perraut, K., Tatulli, E., Thiébaut, E., Young, J., Zins, G., Amorim, A., Aringer, B., Beckert, T., Benisty, M., Bonfils, X., Chelli, A., Chesneau, Olivier, Chiavassa, Andréa, Corradi, Romano L. M., De Becker, M., Delboulbé, A., Duchêne, Gaspard, Forveille, T., Haniff, C., Herwats, E., Hofmann, K.-H., Le Bouquin, Jean Baptiste, Ligori, S., Loreggia, D., Marconi, A., Moitinho, A., Nisini, B., Petrucci, P.-O., Rebordao, J., Speziali, R., Testi, L., Vitali, F., Malbet, F., Buscher, D., Weigelt, G., Garcia, P., Gai, M., Lorenzetti, D, Surdej, J., Hron, Josef, Neuhäuser, R., Kern, P., Jocou, L., Berger, Jean-Philippe, Absil, O., Beckmann, U., Corcione, L., Duvert, G., Filho, M., Labeye, P., Le Coarer, E., Li Causi, G., Lima, J., Perraut, K., Tatulli, E., Thiébaut, E., Young, J., Zins, G., Amorim, A., Aringer, B., Beckert, T., Benisty, M., Bonfils, X., Chelli, A., Chesneau, Olivier, Chiavassa, Andréa, Corradi, Romano L. M., De Becker, M., Delboulbé, A., Duchêne, Gaspard, Forveille, T., Haniff, C., Herwats, E., Hofmann, K.-H., Le Bouquin, Jean Baptiste, Ligori, S., Loreggia, D., Marconi, A., Moitinho, A., Nisini, B., Petrucci, P.-O., Rebordao, J., Speziali, R., Testi, L., and Vitali, F.
Abstract: info:eu-repo/semantics/published
Published: 2009

48. VSI: the VLTI spectro-imager

Author: Malbet, F., Buscher, D., Weigelt, G., Garcia, P., Gai, M., Lorenzetti, D, Surdej, J., Hron, Josef, Neuhäuser, R., Kern, P., Jocou, L., Berger, Jean-Philippe, Absil, O., Beckmann, U., Corcione, L., Duvert, G., Filho, M., Labeye, P., Le Coarer, E., Li Causi, G., Lima, J., Perraut, K., Tatulli, E., Thiébaut, E., Young, J., Zins, G., Amorim, A., Aringer, B., Beckert, T., Benisty, M., Bonfils, X., Cabral, A., Chelli, A., Chesneau, Olivier, Chiavassa, Andréa, Corradi, Romano L. M., De Becker, M., Delboulbé, A., Duch''ne, G., Forveille, T., Haniff, C., Herwats, E., Hofmann, K.-H., Le Bouquin, Jean Baptiste, Ligori, S., Loreggia, D., Marconi, A., Moitinho, A., Nisini, B., Petrucci, P.-O., Rebordao, J., Speziali, R., Testi, L., Vitali, F., Malbet, F., Buscher, D., Weigelt, G., Garcia, P., Gai, M., Lorenzetti, D, Surdej, J., Hron, Josef, Neuhäuser, R., Kern, P., Jocou, L., Berger, Jean-Philippe, Absil, O., Beckmann, U., Corcione, L., Duvert, G., Filho, M., Labeye, P., Le Coarer, E., Li Causi, G., Lima, J., Perraut, K., Tatulli, E., Thiébaut, E., Young, J., Zins, G., Amorim, A., Aringer, B., Beckert, T., Benisty, M., Bonfils, X., Cabral, A., Chelli, A., Chesneau, Olivier, Chiavassa, Andréa, Corradi, Romano L. M., De Becker, M., Delboulbé, A., Duch''ne, G., Forveille, T., Haniff, C., Herwats, E., Hofmann, K.-H., Le Bouquin, Jean Baptiste, Ligori, S., Loreggia, D., Marconi, A., Moitinho, A., Nisini, B., Petrucci, P.-O., Rebordao, J., Speziali, R., Testi, L., and Vitali, F.
Abstract: info:eu-repo/semantics/published
Published: 2008

49. AN INTERFEROMETRIC STUDY OF THE FOMALHAUT INNER DEBRIS DISK. I. NEAR-INFRARED DETECTION OF HOT DUST WITH VLTI/VINCI

Author: Absil, Olivier, primary, Mennesson, Bertrand, additional, Le Bouquin, Jean-Baptiste, additional, Di Folco, Emmanuel, additional, Kervella, Pierre, additional, and Augereau, Jean-Charles, additional
Published: 2009
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