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51. High angular resolution polarimetric imaging of the nucleus of NGC 1068

Author

Grosset, L., Rouan, Daniel, Marin, F., Gratadour, D., Lagadec, E., Hunziker, S., Montargès, M., Magnard, Y., Carle, M., Pragt, J., Petit, C., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), NASA Ames Research Center (ARC), Observatoire de Paris, Université Paris sciences et lettres (PSL), Océan du Large et Variabilité Climatique (OLVAC), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Institute for Particle Physics and Astrophysics [ETH Zürich] (IPA), Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), 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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'Astrophysique de Marseille (LAM), and 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)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Context. Polarisation is a decisive method to study the inner region of active galactic nuclei (AGNs) since, unlike classical imaging, it is not affected by contrast issues. When coupled with high angular resolution (HAR), polarisation can help to disentangle the location of the different polarising mechanisms and then give insight into the physics taking place in the core of AGNs. Aims. We obtained a new data set of HAR polarimetric images of the archetypal Seyfert 2 nucleus of NGC 1068 observed with SPHERE/VLT. We aim in this paper to present the polarisation maps and to spatially separate the location of the polarising mechanisms, thereby deriving constraints on the organisation of the dust material in the inner region of this AGN. Methods. With four new narrow-band images between the visible and the near-infrared combined with older broad-band observations, we studied the wavelength dependence of the polarisation properties from 0.7 to 2.2 μm of three selected regions within the inner 2″ surrounding the central engine. We then compared these measurements to radiative transfer simulations of scattering and dichroic absorption processes, using the Monte Carlo code MontAGN. Results. We establish a detailed table of the relative importance of the polarising mechanism as a function of aperture and wavelength. We are able to separate the dominant polarising mechanisms in the three regions of the ionisation cone, the extended envelope of the torus, and the very central bright source of the AGN. Thus, we estimate the contribution of the different polarisation mechanisms to the observed polarisation flux in these regions. Dichroic absorption is estimated to be responsible for about 99% of the polarised flux coming from the photo-centre. However, this contribution would only be restricted to this location because the double-scattering process would be the most important contributor to polarisation in the equatorial plane of the AGN and single scattering is dominant in the polar outflow bi-cone. Conclusions. Even though results are in good agreement with larger apertures measurements, the variety of situations with different mechanisms at play highlights the importance of spatial resolution for the interpretation of polarisation measurements. We also refine the estimation of the integrated optical depth in the visible of the obscuring structure to a range of 20−100, constraining the geometry of the inner region of this AGN.

Published
2021
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52. A dusty veil shading Betelgeuse during its Great Dimming

Author

Montargès, M., primary, Cannon, E., additional, Lagadec, E., additional, de Koter, A., additional, Kervella, P., additional, Sanchez-Bermudez, J., additional, Paladini, C., additional, Cantalloube, F., additional, Decin, L., additional, Scicluna, P., additional, Kravchenko, K., additional, Dupree, A. K., additional, Ridgway, S., additional, Wittkowski, M., additional, Anugu, N., additional, Norris, R., additional, Rau, G., additional, Perrin, G., additional, Chiavassa, A., additional, Kraus, S., additional, Monnier, J. D., additional, Millour, F., additional, Le Bouquin, J.-B., additional, Haubois, X., additional, Lopez, B., additional, Stee, P., additional, and Danchi, W., additional

Published
2021
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54. The Great Dimming of Betelgeuse from the VLT/VLTI.

Author

Montargès, M., Cannon, E., Lagadec, E., de Koter, A., Kervella, P., Sanchez-Bermudez, J., Paladini, C., Cantalloube, F., Decin, L., Scicluna, P., Kravchenko, K., Dupree, A. K., Ridgway, S., Wittkowski, M., Anugu, N., Norris, R., Rau, G., Perrin, G., Chiavassa, A., and Kraus, S.

Subjects
*GLOBAL dimming, *STELLAR evolution, *SUPERGIANT stars, *STELLAR mass, *VERY Large Telescope (Chile), *VERY large telescope interferometer (Chile), BETELGEUSE
Abstract

From November 2019 to April 2020, the prototypical red supergiant Betelgeuse experienced an unexpected and historic dimming. This event was observed worldwide by astrophysicists, and also by the general public with the naked eye. We present here the results of our observing campaign with ESO's VLT and VLTI in the visible and infrared domains. The observations with VLT/SPHERE-ZIMPOL, VLT/SPHERE-IRDIS, VLTI/GRAVITY and VLTI/MATISSE provide spatially resolved diagnostics of this event. Using PHOENIX atmosphere models and RADMC3D dust radiative transfer simulations, we built a consistent model reproducing the images and the photometry. [ABSTRACT FROM AUTHOR]

Published
2022
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56. The Great Dimming of Betelgeuse from the VLT/VLTI

Author

Montargès, M., primary, Cannon, E., additional, Lagadec, E., additional, de Koter, A., additional, Kervella, P., additional, Sanchez-Bermudez, J., additional, Paladini, C., additional, Cantalloube, F., additional, Decin, L., additional, Scicluna, P., additional, Kravchenko, K., additional, Dupree, A. K., additional, Ridgway, S., additional, Wittkowski, M., additional, Anugu, N., additional, Norris, R., additional, Rau, G., additional, Perrin, G., additional, Chiavassa, A., additional, Kraus, S., additional, Monnier, J. D., additional, Millour, F., additional, Le Bouquin, J.-B., additional, Haubois, X., additional, Lopez, B., additional, Stee, P., additional, and Danchi, W., additional

Published
2020
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57. (Sub)stellar companions shape the winds of evolved stars

Author

Decin, L., primary, Montargès, M., additional, Richards, A. M. S., additional, Gottlieb, C. A., additional, Homan, W., additional, McDonald, I., additional, El Mellah, I., additional, Danilovich, T., additional, Wallström, S. H. J., additional, Zijlstra, A., additional, Baudry, A., additional, Bolte, J., additional, Cannon, E., additional, De Beck, E., additional, De Ceuster, F., additional, de Koter, A., additional, De Ridder, J., additional, Etoka, S., additional, Gobrecht, D., additional, Gray, M., additional, Herpin, F., additional, Jeste, M., additional, Lagadec, E., additional, Kervella, P., additional, Khouri, T., additional, Menten, K., additional, Millar, T. J., additional, Müller, H. S. P., additional, Plane, J. M. C., additional, Sahai, R., additional, Sana, H., additional, Van de Sande, M., additional, Waters, L. B. F. M., additional, Wong, K. T., additional, and Yates, J., additional

Published
2020
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58. 3D reconstruction of the environment of the red supergiant μCep from NOEMA observations of the CO v=0 J=2-1 line

Author

Montargès, M., Homan, W., Keller, D., Clementel, N., Shetye, S., Decin, L., Royer, P., Winters J., M., Le Bertre, T., Richards A. M., S., and bibliotheque, la.

Subjects
supergiants, stars:~mass-loss, stars: individual: μCep, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], circumstellar matter, radio lines: stars, stars: imaging
Abstract

Red supergiant stars are surrounded by a circumstellar environment containing gas and dust. It is created as the star loses its mantle via an unknown mass-loss process. Refining our knowledge of the morphology and physics of such environments is critical to understanding the processes that drive this mass loss. This mass loss phenomenon is also a key element to determine the fate of the star, as it directly determines the mass of the supernova progenitor and hence of the remaining compact object. We present the result of our observations of the CO v=0 J=2-1 emission line of the RSG μ Cep with the NOEMA interferometer at the arcsec angular resolution scale (∼ 500 au at the star distance). Using a combination of 3D deprojection and 3D radiative transfer modeling, we show that at least 25% of the mass loss is due to clumps, randomly arranged in space and emitted episodically by the star.

Published
2019

59. The convective photosphere of the red supergiant CE Tauri

Author

Montargès, M., Norris, R., Chiavassa, A., Tessore, B., Lèbre, A., Baron, F., Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Atlanta], Georgia State University, University System of Georgia (USG)-University System of Georgia (USG), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

International audience; Red supergiant stars are one of the latest stages in the evolution of massive stars. Their photospheric convection may play an important role in the launching mechanism of their mass loss; however, its characteristics and dynamics are still poorly constrained.By observing red supergiant stars with near infrared interferometry at different epochs, we expect to reveal the evolution of bright convective features on their stellar surface.We observed the M2Iab-Ib red supergiant star CE Tau with the VLTI/PIONIER instrument in the H band at two different epochs separated by one month.We derive the angular diameter of the star and basic stellar parameters, and reconstruct two reliable images of its H-band photosphere. The contrast of the convective pattern of the reconstructed images is 5 ± 1% and 6 ± 1% for our two epochs of observation.The stellar photosphere shows few changes between the two epochs. The contrast of the convective pattern is below the average contrast variations obtained on 30 randomly chosen snapshots of the best matching 3D radiative hydrodynamics simulation: 23 ± 1% for the original simulation images and 16 ± 1% for the maps degraded to the reconstruction resolution. We offer two hypotheses to explain this observation. CE Tau may be experiencing a quiet convective activity episode or it could be a consequence of its warmer effective temperature (hence its smaller radius) compared to the simulation.

Published
2018
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61. ALMA observations of the nearby AGB star L 2 Puppis

Author

Kervella, P., Homan, W., Richards, A., Decin, L., Mcdonald, I., Montargès, M., Ohnaka, K., Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester [Manchester], Max-Planck-Institut für Radioastronomie (MPIFR), Instituut voor Sterrenkunde [Leuven], Institut de RadioAstronomie Millimétrique (IRAM), and Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017
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63. The MICADO first light imager for the ELT: overview and current status

Author

Bryant, Julia J., Motohara, Kentaro, Vernet, Joël R. D., Sturm, E., Davies, R., Alves, J., Clénet, Y., Kotilainen, J., Monna, A., Nicklas, H., Pott, J.-U., Tolstoy, E., Vulcani, B., Achren, J., Annadevara, S., Anwand-Heerwart, H., Arcidiacono, C., Barboza, S., Barl, L., Baudoz, P., Bender, R., Bezawada, N., Biondi, F., Bizenberger, P., Blin, A., Boné, A., Bonifacio, P., Borgo, B., Born, J. van den, Buey, T., Cao, Y., Chapron, F., Chauvin, G., Chemla, F., Cloiseau, K., Cohen, M., Colin, C., Czoske, O., Dette, J.-O., Deysenroth, M., Dijkstra, E., Dreizler, S., Dupuis, O., Egmond, G. van, Eisenhauer, F., Elswijk, E., Emslander, A., Fabricius, M., Fasola, G., Ferreira, F., Förster Schreiber, N., Fontana, A., Gaudemard, J., Gautherot, N., Gendron, E., Gennet, C., Genzel, R., Ghouchou, L., Gillessen, S., Gratadour, D., Grazian, A., Grupp, F., Guieu, S., Gullieuszik, M., Haan, M. de, Hartke, J., Hartl, M., Haussmann, F., Helin, T., Hess, H.-J., Hofferbert, R., Huber, H., Huby, E., Huet, J.-M., Ives, D., Janssen, A., Jaufmann, P., Jilg, T., Jodlbauer, D., Jost, J., Kausch, W., Kellermann, H., Kerber, F., Kravcar, H., Kravchenko, K., Kulcsár, C., Kuncarayakti, H., Kunst, P., Kwast, S., Lang, F., Lange, J., Lapeyrere, V., Le Ruyet, B., Leschinski, K., Locatelli, H., Massari, D., Mattila, S., Mei, S., Merlin, F., Meyer, E., Michel, C., Mohr, L., Montargès, M., Müller, F., Münch, N., Navarro, R., Neumann, U., Neumayer, N., Neumeier, L., Pedichini, F., Pflüger, A., Piazzesi, R., Pinard, L., Porras, J., Portulari, E., Przybilla, N., Rabien, S., Raffard, J., Ragazzoni, R., Ramlau, R., Ramos, J., Ramsay, S., Raynaud, H.-F., Rhode, P., Richter, A., Rix, H.-W., Rodenhuis, M., Rohloff, R.-R., Romp, R., Rousselot, P., Sabha, N., Sassolas, B., Schlichter, J., Schuil, M., Schweitzer, M., Seemann, U., Sevin, A., Simioni, M., Spallek, L., Sönmez, A., Suuronen, J., Taburet, S., Thomas, J., Tisserand, E., Vaccari, P., Valenti, E., Verdoes Kleijn, G., Verdugo, M., Vidal, F., Wagner, R., Wegner, M., Winden, D. van, Witschel, J., Zanella, A., Zeilinger, W., Ziegleder, J., and Ziegler, B.

Published
2024
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66. Evolution of the magnetic field of Betelgeuse from 2009–2017

Author

Mathias, P., primary, Aurière, M., additional, López Ariste, A., additional, Petit, P., additional, Tessore, B., additional, Josselin, E., additional, Lèbre, A., additional, Morin, J., additional, Wade, G., additional, Herpin, F., additional, Chiavassa, A., additional, Montargès, M., additional, Konstantinova-Antova, R., additional, Kervella, P., additional, Perrin, G., additional, Donati, J.-F., additional, and Grunhut, J., additional

Published
2018
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68. The SPHERE Data Center: a reference for high contrast imaging processing

Author

Delorme, P., Meunier, N., Albert, D., Lagadec, E., Le Coroller, H., Galicher, R., Mouillet, D., Boccaletti, A., Mesa, D., Meunier, J. -C, Beuzit, J. -L, Lagrange, A. -M, Chauvin, G., Sapone, A., Langlois, M., Maire, A. -L, Montargès, M., Gratton, R., Arthur Vigan, and Surace, C.

Abstract

The objective of the SPHERE Data Center is to optimize the scientific return of SPHERE at the VLT, by providing optimized reduction procedures, services to users and publicly available reduced data. This paper describes our motivation, the implementation of the service (partners, infrastructure and developments), services, description of the on-line data, and future developments. The SPHERE Data Center is operational and has already provided reduced data with a good reactivity to many observers. The first public reduced data have been made available in 2017. The SPHERE Data Center is gathering a strong expertise on SPHERE data and is in a very good position to propose new reduced data in the future, as well as improved reduction procedures.

Published
2017

69. Discovery of a complex linearly polarized spectrum of Betelgeuse dominated by depolarization of the continuum

Author

Konstantinova-Antova R., Agnès Lèbre, Aurière M., Tessore B., Chiavassa A., Kervella P., Josselin E., Donati J.-F., Grunhut J. H., López Ariste A., Mathias P., Wade G. A., Fabrice Herpin, Fabas N., Perrin G., Paletou F., Montargès M., Petit P., 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), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), 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), Bulgarian Academy of Sciences (BAS), Cranfield University, FORMATION STELLAIRE 2016, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Betelgeuse, Physics, Brightness, 010308 nuclear & particles physics, Linear polarization, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Polarization (waves), 01 natural sciences, Spectral line, symbols.namesake, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, symbols, Astrophysics::Solar and Stellar Astrophysics, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Rayleigh scattering, Supergiant, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Betelgeuse is an M supergiant that harbors spots and giant granules at its surface and presents linear polarization of its continuum. We have previously discovered linear polarization signatures associated with individual lines in the spectra of cool and evolved stars. Here, we investigate whether a similar linearly polarized spectrum exists for Betelgeuse. We used the spectropolarimeter Narval, combining multiple polarimetric sequences to obtain high signal-to-noise ratio spectra of individual lines, as well as the least-squares deconvolution (LSD) approach. We have discovered the existence of a linearly polarized spectrum for Betelgeuse, detecting a rather strong signal (at a few times 10$^{-4}$ of the continuum intensity level), both in individual lines and in the LSD profiles. Studying its properties and the signal observed for the resonant \ion{Na}{i}\,D lines, we conclude that we are mainly observing depolarization of the continuum by the absorption lines. The linear polarization of the Betelgeuse continuum is due to the anisotropy of the radiation field induced by brightness spots at the surface and Rayleigh scattering in the atmosphere. We have developed a geometrical model to interpret the observed polarization, from which we infer the presence of two brightness spots and their positions on the surface of Betelgeuse. We show that applying the model to each velocity bin along the Stokes Q and U profiles allows the derivation of a map of the bright spots. We use the Narval linear polarization observations of Betelgeuse obtained over a period of 1.4 years to study the evolution of the spots. Our study of the linearly polarized spectrum of Betelgeuse provides a novel method for studying the evolution of brightness spots at its surface and complements quasi-simultaneous observations obtained with PIONIER at the VLTI., 13 pages, 10 figures, accepted for publication in Astronomy and Astrophysics

Published
2016
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70. The close circumstellar environment of Betelgeuse

Author

Kervella, P., Lagadec, Erwan, Lagadec, Eric, Montargès, M., Ridgway, S., Chiavassa, A., Haubois, X., Schmid, H.-M., Langlois, M., Gallenne, A., Perrin, G., 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), 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), Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), National Optical Astronomy Observatory (NOAO), European Southern Observatory (ESO), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire de Modélisation et Simulation Multi Echelle (MSME), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Paris-Est Marne-la-Vallée (UPEM), 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), 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), Université Paris-Est Marne-la-Vallée (UPEM)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-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), 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), and National Optical Astronomical Observatory (NOAO)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016
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73. Asymmetries on red giant branch surfaces from CHARA/MIRC optical interferometry

Author

Chiavassa, A., primary, Norris, R., additional, Montargès, M., additional, Ligi, R., additional, Fossati, L., additional, Bigot, L., additional, Baron, F., additional, Kervella, P., additional, Monnier, J. D., additional, Mourard, D., additional, Nardetto, N., additional, Perrin, G., additional, Schaefer, G. H., additional, ten Brummelaar, T. A., additional, Magic, Z., additional, Collet, R., additional, and Asplund, M., additional

Published
2017
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74. The dust disk and companion of the nearby AGB star L 2 Puppis

Author

Kervella, P., Montargès, M., Lagadec, Eric, Ridgway, S., Haubois, X., Girard, J., Ohnaka, K., Perrin, G., Gallenne, A., Laboratoire Franco-Chilien d'Astronomie (LFCA), Universidad de Chile = University of Chile [Santiago] (UCHILE)-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Concepción - University of Concepcion [Chile], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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), National Optical Astronomy Observatory (NOAO), 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), Max-Planck-Institut für Radioastronomie (MPIFR), Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Chile, Université Nice Sophia Antipolis (... - 2019) (UNS), 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 National de la Recherche Scientifique (CNRS)-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)-Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Universidad de Chile-Institut national des sciences de l'Univers (INSU - CNRS), 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 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)

Subjects
[PHYS]Physics [physics], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015
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75. NOEMA maps the CO J = 2 − 1 environment of the red supergiant |$\mu$| Cep.

Author

Montargès, M, Homan, W, Keller, D, Clementel, N, Shetye, S, Decin, L, Harper, G M, Royer, P, Winters, J M, Le Bertre, T, and Richards, A M S

Subjects
SUPERGIANT stars, HEAVY elements, WIND speed, INTERSTELLAR medium, CIRCUMSTELLAR matter, RADIATIVE transfer
Abstract

Red supergiant stars are surrounded by a gaseous and dusty circumstellar environment created by their mass loss, which spreads heavy elements into the interstellar medium. The structure and dynamics of this envelope are crucial to understand the processes driving the red supergiant mass loss and the shaping of the pre-supernova ejecta. We have observed the emission from the CO J  = 2 − 1 line from the red supergiant star |$\mu$|  Cep with the NOEMA interferometer. In the line the synthesized beam was 0.92 × 0.72 arcsec (590 × 462 au at 641 pc). The continuum map shows only the unresolved contribution of the free–free emission of the star chromosphere. The continuum-subtracted channel maps reveal a very inhomogeneous and clumpy circumstellar environment. In particular, we detected a bright CO clump, as bright as the central source in the line, at 1.80 arcsec south-west from the star, in the blue channel maps. After a deprojection of the radial velocity assuming two different constant wind velocities, the observations were modelled using the 3D radiative transfer code lime to derive the characteristics of the different structures. We determine that the gaseous clumps observed around |$\mu$|  Cep are responsible for a mass-loss rate of |$(4.9 \pm 1.0) \times 10^{-7}\, {\rm M}_\odot \, {\rm yr}^{-1}$|⁠, in addition to a spatially unresolved wind component with an estimated mass-loss rate of |$2.0 \times 10^{-6}\, {\rm M}_\odot \, {\rm yr}^{-1}$|⁠. Therefore, the clumps have a significant role in |$\mu$|  Cep's mass loss (⁠|$\ge 25 {{\ \rm per\ cent}}$|⁠). We cannot exclude that the unresolved central outflow may be made of smaller unresolved clumps. [ABSTRACT FROM AUTHOR]

Published
2019
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77. Discovery of a complex linearly polarized spectrum of Betelgeuse dominated by depolarization of the continuum

Author

Aurière, M., primary, López Ariste, A., additional, Mathias, P., additional, Lèbre, A., additional, Josselin, E., additional, Montargès, M., additional, Petit, P., additional, Chiavassa, A., additional, Paletou, F., additional, Fabas, N., additional, Konstantinova-Antova, R., additional, Donati, J.-F., additional, Grunhut, J. H., additional, Wade, G. A., additional, Herpin, F., additional, Kervella, P., additional, Perrin, G., additional, and Tessore, B., additional

Published
2016
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78. The close circumstellar environment of Betelgeuse

Author

Montargès, M., primary, Kervella, P., additional, Perrin, G., additional, Chiavassa, A., additional, Le Bouquin, J.-B., additional, Aurière, M., additional, López Ariste, A., additional, Mathias, P., additional, Ridgway, S. T., additional, Lacour, S., additional, Haubois, X., additional, and Berger, J.-P., additional

Published
2016
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79. The close circumstellar environment of Betelgeuse

Author

Kervella, P., primary, Lagadec, E., additional, Montargès, M., additional, Ridgway, S. T., additional, Chiavassa, A., additional, Haubois, X., additional, Schmid, H.-M., additional, Langlois, M., additional, Gallenne, A., additional, and Perrin, G., additional

Published
2015
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81. The inhomogeneous submillimeter atmosphere of Betelgeuse.

Author

O'Gorman, E., Kervella, P., Harper, G. M., Richards, A. M. S., Decin, L., Montargès, M., and McDonald, I.

Subjects
SOLAR photosphere, ATMOSPHERE, TEMPERATURE inversions, SUPERGIANT stars, STELLAR atmospheres, HARD disks, STELLAR evolution
Abstract

The mechanisms responsible for heating the extended atmospheres of early-M spectral-type supergiants are poorly understood. So too is the subsequent role these mechanisms play in driving the large mass-loss rates of these stars. Here we present ALMA long (i.e., ~16 km) baseline 338 GHz (0.89 mm) continuum observations of the free-free emission in the extended atmosphere of the M2 spectral-type supergiant Betelgeuse. The spatial resolution of 14 mas exquisitely resolves the atmosphere, revealing it to have a mean temperature of 2760K at ~1.3 R*, which is below both the photospheric effective temperature (Teff = 3690 K) and the temperatures at ~2 R*. This is unambiguous proof for the existence of an inversion of the mean temperature in the atmosphere of a red supergiant. The emission is clearly not spherically symmetric with two notable deviations from a uniform disk detected in both the images and visibilities. The most prominent asymmetry is located in the north-east quadrant of the disk and is spatially resolved showing it to be highly elongated with an axis-ratio of 2.4 and occupying ~5% of the disk projected area. Its temperature is approximately 1000K above the measured mean temperature at 1.3 R*. The other main asymmetry is located on the disk limb almost due east of the disk center and occupies ~3% of the disk projected area. Both emission asymmetries are clear evidence for localized heating taking place in the atmosphere of Betelgeuse. We suggest that the detected localized heating is related to magnetic activity generated by large-scale photospheric convection. [ABSTRACT FROM AUTHOR]

Published
2017
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90. THE NEARBY AGB STAR L2 PUPPIS: THE BIRTH OF A PLANETARY NEBULA?

Author

Kervella, P., Montargès, M., and Lagadec, E.

Subjects
ASYMPTOTIC giant branch stars, PLANETARY nebulae, ADAPTIVE optics, EMISSION control, BIPOLAR outflows (Astrophysics)
Abstract

Adaptive optics observations in the infrared (VLT/NACO, Kervella et al. 2014) and visible (VLT/SPHERE, Kervella et al. 2015) domains revealed that the nearby AGB star L2 Pup (d = 64pc) is surrounded by a dust disk seen almost edge-on. Thermal emission from a large dust "loop" is detected at 4 μm up to more than 10AU from the star. We also detect a secondary source at a separation of 32mas, whose nature is uncertain. L2 Pup is currently a relatively "young" AGB star, so we may witness the formation of a planetary nebula. The mechanism that breaks the spherical symmetry of mass loss is currently uncertain, but we propose that the dust disk and companion are key elements in the shaping of the bipolar structure. L2 Pup emerges as an important system to test this hypothesis. [ABSTRACT FROM AUTHOR]

Published
2015
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91. An edge-on translucent dust disk around the nearest AGB star, L2 Puppis.

Author

Kervella, P., Montargès, M., Ridgway, S. T., Perrin, G., Chesneau, O., Lacour, S., Chiavassa, A., Haubois, X., and Gallenne, A.

Subjects
*ASYMPTOTIC giant branch stars, *STELLAR evolution, *WAVELENGTHS, *STARS, *NEBULAE, *ANGULAR diameter (Astronomy)
Abstract

As the nearest known AGB star (d = 64 pc) and one of the brightest (mK ≈ -2), L2 Pup is a particularly interesting benchmark object to monitor the final stages of stellar evolution. We report new serendipitous imaging observations of this star with the VLT/NACO adaptive optics system in twelve narrow-band filters covering the 1:0-4:0 μm wavelength range. These di raction-limited images reveal an extended circumstellar dust lane in front of the star that exhibits a high opacity in the J band and becomes translucent in the H and K bands. In the L band, extended thermal emission from the dust is detected. We reproduced these observations using Monte Carlo radiative transfer modeling of a dust disk with the RADMC-3D code. We also present new interferometric observations with the VLTI/VINCI and MIDI instruments. We measured in the K band an upper limit to the limb-darkened angular diameter of θLD = 17:9 ± 1:6 mas, converting to a maximum linear radius of R = 123 ± 14 R☉ Considering the geometry of the extended K band emission in the NACO images, this upper limit is probably close to the actual angular diameter of the star. The position of L2 Pup in the Hertzsprung-Russell diagram indicates that this star has a mass of about 2 M☉ and is probably experiencing an early stage of the asymptotic giant branch. We did not detect any stellar companion of L2 Pup in our adaptive optics and interferometric observations, and we attribute its apparent astrometric wobble in the Hipparcos data to variable lighting effects on its circumstellar material. However, we do not exclude the presence of a binary companion, because the large loop structure extending to more than 10 AU to the northeast of the disk in our L-band images may be the result of interaction between the stellar wind of L2 Pup and a hidden secondary object. The geometric configuration that we propose, with a large dust disk seen almost edge-on, appears particularly favorable to test and develop our understanding of the formation of bipolar nebulae. [ABSTRACT FROM AUTHOR]

Published
2014
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92. Imaging the Great Dimming of Betelgeuse

Author

Montargès, M., Cannon, E., Lagadec, E., de Koter, A., Kervella, P., Sanchez-Bermudez, J., Paladini, C., Cantalloube, F., Decin, L., Scicluna, P., Kravchenko, K., Dupree, A. K., Ridgway, S., Wittkowski, M., Anugu, N., Norris, R., Rau, G., Perrin, G., Chiavassa, A., Kraus, S., Monnier, J. D., Millour, F., Le Bouquin, J. -B., Haubois, X., Lopez, B., Stee, P., Danchi, W., and Montargès, M.

Subjects
Stars: evolution, 13. Climate action, supergiants, Stars: mass-loss, Stars: individual: Betelgeuse
Abstract

From November 2019 to April 2020, the prototypical red supergiant Betelgeuse experienced an unexpected and historic dimming. This event was observed worldwide by astrophysicists, and also by the general public with the naked eye. I will present the results of our observing campaign with ESO's VLT and VLTI in the visible and near infrared domains. The observations with SPHERE-ZIMPOL, SPHERE-IRDIS and GRAVITY provide spatially resolved diagnostics of this event. Using PHOENIX atmosphere models and RADMC3D dust radiative transfer simulations, we built a consistent model reproducing the images and the photometry.

93. Imaging the Great Dimming of Betelgeuse

Author

Montargès, M., Cannon, E., Lagadec, E., de Koter, A., Kervella, P., Sanchez-Bermudez, J., Paladini, C., Cantalloube, F., Decin, L., Scicluna, P., Kravchenko, K., Dupree, A. K., Ridgway, S., Wittkowski, M., Anugu, N., Norris, R., Rau, G., Perrin, G., Chiavassa, A., Kraus, S., Monnier, J. D., Millour, F., Le Bouquin, J. -B., Haubois, X., Lopez, B., Stee, P., and Danchi, W.

Subjects
Stars: evolution, 13. Climate action, supergiants, Stars: mass-loss, Stars: individual: Betelgeuse
Abstract

From November 2019 to April 2020, the prototypical red supergiant Betelgeuse experienced an unexpected and historic dimming. This event was observed worldwide by astrophysicists, and also by the general public with the naked eye. I will present the results of our observing campaign with ESO's VLT and VLTI in the visible and near infrared domains. The observations with SPHERE-ZIMPOL, SPHERE-IRDIS and GRAVITY provide spatially resolved diagnostics of this event. Using PHOENIX atmosphere models and RADMC3D dust radiative transfer simulations, we built a consistent model reproducing the images and the photometry., {"references":["Refereed publication: Montargès et al. 2021, https://doi.org/10.1038/s41586-021-03546-8"]}

94. Chemical tracers of a highly eccentric AGB–main-sequence star binary

Author

Danilovich, T., Malfait, J., Van de Sande, M., Montargès, M., Kervella, P., De Ceuster, F., Coenegrachts, A., Millar, T. J., Richards, A. M. S., Decin, L., Gottlieb, C. A., Pinte, C., De Beck, E., Price, D. J., Wong, K. T., Bolte, J., Menten, K. M., Baudry, A., de Koter, A., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Lagadec, E., Maes, S., McDonald, I., Marinho, L., Müller, H. S. P., Pimpanuwat, B., Plane, J. M. C., Sahai, R., Wallström, S. H. J., Yates, J., Zijlstra, A., Danilovich, T., Malfait, J., Van de Sande, M., Montargès, M., Kervella, P., De Ceuster, F., Coenegrachts, A., Millar, T. J., Richards, A. M. S., Decin, L., Gottlieb, C. A., Pinte, C., De Beck, E., Price, D. J., Wong, K. T., Bolte, J., Menten, K. M., Baudry, A., de Koter, A., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Lagadec, E., Maes, S., McDonald, I., Marinho, L., Müller, H. S. P., Pimpanuwat, B., Plane, J. M. C., Sahai, R., Wallström, S. H. J., Yates, J., and Zijlstra, A.

Abstract

Binary interactions have been proposed to explain a variety of circumstellar structures seen around evolved stars, including asymptotic giant branch (AGB) stars and planetary nebulae. Studies resolving the circumstellar envelopes of AGB stars have revealed spirals, disks and bipolar outflows, with shaping attributed to interactions with a companion. Here we use a combined chemical and dynamical analysis to reveal a highly eccentric and long-period orbit for W Aquilae, a binary system containing an AGB star and a main-sequence companion. Our results are based on anisotropic SiN emission, the detections of irregular NS and SiC emission towards the S-type star, and density structures observed in the CO emission. These features are all interpreted as having formed during periastron interactions. Our astrochemistry-based method can yield stringent constraints on the orbital parameters of long-period binaries containing AGB stars, and will be applicable to other systems.

95. ATOMIUM: halide molecules around the S-type AGB star W Aquilae

Author

Danilovich, T., Van de Sande, M., Plane, J. M. C., Millar, T. J., Royer, P., Amor, M. A., Hammami, K., Decock, L., Gottlieb, C. A., Decin, L., Richards, A. M. S., De Beck, E., Baudry, A., Bolte, J., Cannon, E., De Ceuster, F., de Koter, A., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Homan, W., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., McDonald, I., Menten, K. M., Montargès, M., Müller, H. S. P., Pimpanuwat, B., Sahai, R., Wallström, S. H. J., Waters, L. B. F. M., Wong, K. T., Yates, J., Zijlstra, A., Danilovich, T., Van de Sande, M., Plane, J. M. C., Millar, T. J., Royer, P., Amor, M. A., Hammami, K., Decock, L., Gottlieb, C. A., Decin, L., Richards, A. M. S., De Beck, E., Baudry, A., Bolte, J., Cannon, E., De Ceuster, F., de Koter, A., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Homan, W., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., McDonald, I., Menten, K. M., Montargès, M., Müller, H. S. P., Pimpanuwat, B., Sahai, R., Wallström, S. H. J., Waters, L. B. F. M., Wong, K. T., Yates, J., and Zijlstra, A.

Abstract

Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. W Aql is a nearby S-type star, with well-known circumstellar parameters, making it an ideal object for in-depth study of less common molecules. Aims. We aim to determine the abundances of AlCl and AlF from rotational lines, which have been observed for the first time towards an S-type AGB star. In combination with models based on PACS observations, we aim to update our chemical kinetics network based on these results. Methods. We analyse ALMA observations towards W Aql of AlCl in the ground and first two vibrationally excited states and AlF in the ground vibrational state. Using radiative transfer models, we determine the abundances and spatial abundance distributions of Al35Cl, Al37Cl, and AlF. We also model HCl and HF emission and compare these models to PACS spectra to constrain the abundances of these species. Results. AlCl is found in clumps very close to the star, with emission confined within 0′′.1 of the star. AlF emission is more extended, with faint emission extending 0′′.2 to 0′′.6 from the continuum peak. We find peak abundances, relative to H2, of 1.7 × 10−7 for Al35Cl, 7 × 10−8 for Al37Cl, and 1 × 10−7 for AlF. From the PACS spectra, we find abundances of 9.7 × 10−8 and ≤10−8, relative to H2, for HCl and HF, respectively. Conclusions. The AlF abundance exceeds the solar F abundance, indicating that fluorine synthesised in the AGB star has already been dredged up to the surface of the star and ejected into the circumstellar e

96. (Sub)stellar companions shape the winds of evolved stars

Author

Decin, L., Montargès, M., Richards, A. M. S., Gottlieb, C. A., Homan, W., Mcdonald, I., El Mellah, I., Danilovich, T., Wallström, S. H. J., Zijlstra, A., Baudry, A., Bolte, J., Cannon, E., De Beck, E., De Ceuster, F., de Koter, A., De Ridder, J., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Lagadec, E., Kervella, P., Khouri, T., Menten, K., Millar, T. J., Müller, H. S. P., Plane, J. M. C., Sahai, R., Sana, H., Van de Sande, M., Waters, L. B. F. M., Wong, K. T., Yates, J., Decin, L., Montargès, M., Richards, A. M. S., Gottlieb, C. A., Homan, W., Mcdonald, I., El Mellah, I., Danilovich, T., Wallström, S. H. J., Zijlstra, A., Baudry, A., Bolte, J., Cannon, E., De Beck, E., De Ceuster, F., de Koter, A., De Ridder, J., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Lagadec, E., Kervella, P., Khouri, T., Menten, K., Millar, T. J., Müller, H. S. P., Plane, J. M. C., Sahai, R., Sana, H., Van de Sande, M., Waters, L. B. F. M., Wong, K. T., and Yates, J.

Abstract

Binary interactions dominate the evolution of massive stars, but their role is less clear for low- and intermediate-mass stars. The evolution of a spherical wind from an asymptotic giant branch (AGB) star into a nonspherical planetary nebula (PN) could be due to binary interactions. We observed a sample of AGB stars with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that their winds exhibit distinct nonspherical geometries with morphological similarities to planetary nebulae (PNe). We infer that the same physics shapes both AGB winds and PNe; additionally, the morphology and AGB mass-loss rate are correlated. These characteristics can be explained by binary interaction. We propose an evolutionary scenario for AGB morphologies that is consistent with observed phenomena in AGB stars and PNe.

97. ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars

Author

Gottlieb, C. A., Decin, L., Richards, A. M. S., De Ceuster, F., Homan, W., Wallström, S. H. J., Danilovich, T., Millar, T. J., Montargès, M., Wong, K. T., McDonald, I., Baudry, A., Bolte, J., Cannon, E., De Beck, E., de Koter, A., El Mellah, I., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., Menten, K. M., Müller, H. S. P., Pimpanuwat, B., Plane, J. M. C., Sahai, R., Van de Sande, M., Waters, L. B. F. M., Yates, J., Zijlstra, A., Gottlieb, C. A., Decin, L., Richards, A. M. S., De Ceuster, F., Homan, W., Wallström, S. H. J., Danilovich, T., Millar, T. J., Montargès, M., Wong, K. T., McDonald, I., Baudry, A., Bolte, J., Cannon, E., De Beck, E., de Koter, A., El Mellah, I., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., Menten, K. M., Müller, H. S. P., Pimpanuwat, B., Plane, J. M. C., Sahai, R., Van de Sande, M., Waters, L. B. F. M., Yates, J., and Zijlstra, A.

Abstract

This overview paper presents ATOMIUM, a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry in the winds of evolved asymptotic giant branch (AGB) and red supergiant (RSG) stars. A more general aim is to identify chemical processes applicable to other astrophysical environments. Seventeen oxygen-rich AGB and RSG stars spanning a range in (circum)stellar parameters and evolutionary phases were observed in a homogeneous observing strategy allowing for an unambiguous comparison. Data were obtained between 213.83 and 269.71 GHz at high (∼0″​​.025–0″​​.050), medium (∼0″​​.13–0″​​.24), and low (∼1″) angular resolution. The sensitivity per ∼1.3 km s−1 channel was 1.5–5 mJy beam−1, and the line-free channels were used to image the millimetre wave continuum. Our primary molecules for studying the gas dynamics and dust formation are CO, SiO, AlO, AlOH, TiO, TiO2, and HCN; secondary molecules include SO, SO2, SiS, CS, H2O, and NaCl. The scientific motivation, survey design, sample properties, data reduction, and an overview of the data products are described. In addition, we highlight one scientific result – the wind kinematics of the ATOMIUM sources. Our analysis suggests that the ATOMIUM sources often have a slow wind acceleration, and a fraction of the gas reaches a velocity which can be up to a factor of two times larger than previously reported terminal velocities assuming isotropic expansion. Moreover, the wind kinematic profiles establish that the radial velocity described by the momentum equation for a spherical wind structure cannot capture the complexity of the velocity field. In fifteen sources, some molecular transitions other than 12CO v = 0 J = 2 − 1 reach a higher outflow velocity, with a spatial emission zone that is often greater than 30 stellar radii, but m

98. The VLT/SPHERE view of the ATOMIUM cool evolved star sample

Author

Montargès, M., Cannon, E., de Koter, A., Khouri, T., Lagadec, E., Kervella, P., Decin, L., McDonald, I., Homan, W., Waters, L. B. F. M., Sahai, R., Gottlieb, C. A., Malfait, J., Maes, S., Pimpanuwat, B., Jeste, M., Danilovich, T., De Ceuster, F., Van de Sande, M., Gobrecht, D., Wallström, S. H. J., Wong, K. T., El Mellah, I., Bolte, J., Herpin, F., Richards, A. M. S., Baudry, A., Etoka, S., Gray, M. D., Millar, T. J., Menten, K. M., Müller, H. S. P., Plane, J. M. C., Yates, J., Zijlstra, A., Montargès, M., Cannon, E., de Koter, A., Khouri, T., Lagadec, E., Kervella, P., Decin, L., McDonald, I., Homan, W., Waters, L. B. F. M., Sahai, R., Gottlieb, C. A., Malfait, J., Maes, S., Pimpanuwat, B., Jeste, M., Danilovich, T., De Ceuster, F., Van de Sande, M., Gobrecht, D., Wallström, S. H. J., Wong, K. T., El Mellah, I., Bolte, J., Herpin, F., Richards, A. M. S., Baudry, A., Etoka, S., Gray, M. D., Millar, T. J., Menten, K. M., Müller, H. S. P., Plane, J. M. C., Yates, J., and Zijlstra, A.

Abstract

Context. Low- and intermediate-mass asymptotic giant stars and massive red supergiant stars are important contributors to the chemical enrichment of the Universe. They are among the most efficient dust factories of the Galaxy, harboring chemically rich circumstellar environments. Yet, the processes that lead to dust formation or the large-scale shaping of the mass loss still escape attempts at modeling. Aims. Through the ATOMIUM project, we aim to present a consistent view of a sample of 17 nearby cool evolved stars. Our goals are to unveil the dust-nucleation sites and morphologies of the circumstellar envelope of such stars and to probe ambient environments with various conditions. This will further enhance our understanding of the roles of stellar convection and pulsations, and that of companions in shaping the dusty circumstellar medium. Methods. Here we present and analyze VLT/SPHERE-ZIMPOL polarimetric maps obtained in the visible (645–820 nm) of 14 out of the 17 ATOMIUM sources. They were obtained contemporaneously with the ALMA high spatial resolution data. To help interpret the polarized signal, we produced synthetic maps of light scattering by dust, through 3D radiative transfer simulations with the RADMC3D code. Results. The degree of linear polarization (DoLP) observed by ZIMPOL spreads across several optical filters. We infer that it primarily probes dust located just outside of the point spread function of the central source, and in or near the plane of the sky. The polarized signal is mainly produced by structures with a total optical depth close to unity in the line of sight, and it represents only a fraction of the total circumstellar dust. The maximum DoLP ranges from 0.03–0.38 depending on the source, fractions that can be reproduced by our 3D pilot models for grains composed of olivine, melilite, corundum, enstatite, or forsterite. The spatial structure of the DoLP

99. ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars

Author

Gottlieb, C. A., Decin, L., Richards, A. M. S., De Ceuster, F., Homan, W., Wallström, S. H. J., Danilovich, T., Millar, T. J., Montargès, M., Wong, K. T., McDonald, I., Baudry, A., Bolte, J., Cannon, E., De Beck, E., de Koter, A., El Mellah, I., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., Menten, K. M., Müller, H. S. P., Pimpanuwat, B., Plane, J. M. C., Sahai, R., Van de Sande, M., Waters, L. B. F. M., Yates, J., Zijlstra, A., Gottlieb, C. A., Decin, L., Richards, A. M. S., De Ceuster, F., Homan, W., Wallström, S. H. J., Danilovich, T., Millar, T. J., Montargès, M., Wong, K. T., McDonald, I., Baudry, A., Bolte, J., Cannon, E., De Beck, E., de Koter, A., El Mellah, I., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., Menten, K. M., Müller, H. S. P., Pimpanuwat, B., Plane, J. M. C., Sahai, R., Van de Sande, M., Waters, L. B. F. M., Yates, J., and Zijlstra, A.

Abstract

This overview paper presents ATOMIUM, a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry in the winds of evolved asymptotic giant branch (AGB) and red supergiant (RSG) stars. A more general aim is to identify chemical processes applicable to other astrophysical environments. Seventeen oxygen-rich AGB and RSG stars spanning a range in (circum)stellar parameters and evolutionary phases were observed in a homogeneous observing strategy allowing for an unambiguous comparison. Data were obtained between 213.83 and 269.71 GHz at high (∼0″​​.025–0″​​.050), medium (∼0″​​.13–0″​​.24), and low (∼1″) angular resolution. The sensitivity per ∼1.3 km s−1 channel was 1.5–5 mJy beam−1, and the line-free channels were used to image the millimetre wave continuum. Our primary molecules for studying the gas dynamics and dust formation are CO, SiO, AlO, AlOH, TiO, TiO2, and HCN; secondary molecules include SO, SO2, SiS, CS, H2O, and NaCl. The scientific motivation, survey design, sample properties, data reduction, and an overview of the data products are described. In addition, we highlight one scientific result – the wind kinematics of the ATOMIUM sources. Our analysis suggests that the ATOMIUM sources often have a slow wind acceleration, and a fraction of the gas reaches a velocity which can be up to a factor of two times larger than previously reported terminal velocities assuming isotropic expansion. Moreover, the wind kinematic profiles establish that the radial velocity described by the momentum equation for a spherical wind structure cannot capture the complexity of the velocity field. In fifteen sources, some molecular transitions other than 12CO v = 0 J = 2 − 1 reach a higher outflow velocity, with a spatial emission zone that is often greater than 30 stellar radii, but m

100. ATOMIUM: halide molecules around the S-type AGB star W Aquilae

Author

Danilovich, T., Van de Sande, M., Plane, J. M. C., Millar, T. J., Royer, P., Amor, M. A., Hammami, K., Decock, L., Gottlieb, C. A., Decin, L., Richards, A. M. S., De Beck, E., Baudry, A., Bolte, J., Cannon, E., De Ceuster, F., de Koter, A., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Homan, W., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., McDonald, I., Menten, K. M., Montargès, M., Müller, H. S. P., Pimpanuwat, B., Sahai, R., Wallström, S. H. J., Waters, L. B. F. M., Wong, K. T., Yates, J., Zijlstra, A., Danilovich, T., Van de Sande, M., Plane, J. M. C., Millar, T. J., Royer, P., Amor, M. A., Hammami, K., Decock, L., Gottlieb, C. A., Decin, L., Richards, A. M. S., De Beck, E., Baudry, A., Bolte, J., Cannon, E., De Ceuster, F., de Koter, A., Etoka, S., Gobrecht, D., Gray, M., Herpin, F., Homan, W., Jeste, M., Kervella, P., Khouri, T., Lagadec, E., Maes, S., Malfait, J., McDonald, I., Menten, K. M., Montargès, M., Müller, H. S. P., Pimpanuwat, B., Sahai, R., Wallström, S. H. J., Waters, L. B. F. M., Wong, K. T., Yates, J., and Zijlstra, A.

Abstract

Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. W Aql is a nearby S-type star, with well-known circumstellar parameters, making it an ideal object for in-depth study of less common molecules. Aims. We aim to determine the abundances of AlCl and AlF from rotational lines, which have been observed for the first time towards an S-type AGB star. In combination with models based on PACS observations, we aim to update our chemical kinetics network based on these results. Methods. We analyse ALMA observations towards W Aql of AlCl in the ground and first two vibrationally excited states and AlF in the ground vibrational state. Using radiative transfer models, we determine the abundances and spatial abundance distributions of Al35Cl, Al37Cl, and AlF. We also model HCl and HF emission and compare these models to PACS spectra to constrain the abundances of these species. Results. AlCl is found in clumps very close to the star, with emission confined within 0′′.1 of the star. AlF emission is more extended, with faint emission extending 0′′.2 to 0′′.6 from the continuum peak. We find peak abundances, relative to H2, of 1.7 × 10−7 for Al35Cl, 7 × 10−8 for Al37Cl, and 1 × 10−7 for AlF. From the PACS spectra, we find abundances of 9.7 × 10−8 and ≤10−8, relative to H2, for HCl and HF, respectively. Conclusions. The AlF abundance exceeds the solar F abundance, indicating that fluorine synthesised in the AGB star has already been dredged up to the surface of the star and ejected into the circumstellar e

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