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443 results on '"Le Bouquin, J. B."'

1. The cool brown dwarf Gliese 229 B is a close binary

Author: Xuan, Jerry W., Mérand, A., Thompson, W., Zhang, Y., Lacour, S., Blakely, D., Mawet, D., Oppenheimer, R., Kammerer, J., Batygin, K., Sanghi, A., Wang, J., Ruffio, J.-B., Liu, M. C., Knutson, H., Brandner, W., Burgasser, A., Rickman, E., Bowens-Rubin, R., Salama, M., Balmer, W., Blunt, S., Bourdarot, G., Caselli, P., Chauvin, G., Davies, R., Drescher, A., Eckart, A., Eisenhauer, F., Fabricius, M., Feuchtgruber, H., Finger, G., Förster Schreiber, N. M., Garcia, P., Genzel, R., Gillessen, S., Grant, S., Hartl, M., Haußmann, F., Henning, T., Hinkley, S., Hönig, S. F., Horrobin, M., Houllé, M., Janson, M., Kervella, P., Kral, Q., Kreidberg, L., Le Bouquin, J.-B., Lutz, D., Mang, F., Marleau, G.-D., Millour, F., More, N., Nowak, M., Ott, T., Otten, G., Paumard, T., Rabien, S., Rau, C., Ribeiro, D. C., Sadun Bordoni, M., Sauter, J., Shangguan, J., Shimizu, T. T., Sykes, C., Soulain, A., Spezzano, S., Straubmeier, C., Stolker, T., Sturm, E., Subroweit, M., Tacconi, L. J., van Dishoeck, E. F., Vigan, A., Widmann, F., Wieprecht, E., Winterhalder, T. O., and Woillez, J.
Published: 2024
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2. A dynamical measure of the black hole mass in a quasar 11 billion years ago

Author: Abuter, R., Allouche, F., Amorim, A., Bailet, C., Berdeu, A., Berger, J.-P., Berio, P., Bigioli, A., Boebion, O., Bolzer, M.-L., Bonnet, H., Bourdarot, G., Bourget, P., Brandner, W., Cao, Y., Conzelmann, R., Comin, M., Clénet, Y., Courtney-Barrer, B., Davies, R., Defrère, D., Delboulbé, A., Delplancke-Ströbele, F., Dembet, R., Dexter, J., de Zeeuw, P. T., Drescher, A., Eckart, A., Édouard, C., Eisenhauer, F., Fabricius, M., Feuchtgruber, H., Finger, G., Förster Schreiber, N. M., Garcia, P., Garcia Lopez, R., Gao, F., Gendron, E., Genzel, R., Gil, J. P., Gillessen, S., Gomes, T., Gonté, F., Gouvret, C., Guajardo, P., Guieu, S., Hackenberg, W., Haddad, N., Hartl, M., Haubois, X., Haußmann, F., Heißel, G., Henning, Th., Hippler, S., Hönig, S. F., Horrobin, M., Hubin, N., Jacqmart, E., Jocou, L., Kaufer, A., Kervella, P., Kolb, J., Korhonen, H., Lacour, S., Lagarde, S., Lai, O., Lapeyrère, V., Laugier, R., Le Bouquin, J.-B., Leftley, J., Léna, P., Lewis, S., Liu, D., Lopez, B., Lutz, D., Magnard, Y., Mang, F., Marcotto, A., Maurel, D., Mérand, A., Millour, F., More, N., Netzer, H., Nowacki, H., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Paumard, T., Perraut, K., Perrin, G., Petrov, R., Pfuhl, O., Pourré, N., Rabien, S., Rau, C., Riquelme, M., Robbe-Dubois, S., Rochat, S., Salman, M., Sanchez-Bermudez, J., Santos, D. J. D., Scheithauer, S., Schöller, M., Schubert, J., Schuhler, N., Shangguan, J., Shchekaturov, P., Shimizu, T. T., Sevin, A., Soulez, F., Spang, A., Stadler, E., Sternberg, A., Straubmeier, C., Sturm, E., Sykes, C., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Uysal, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., and Zins, G.
Published: 2024
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3. Estimation of the lateral mis-registrations of the GRAVITY+ adaptive optics system. Perturbative method with open-loop modal correlation and non-pertubative method with temporal correlation of closed-loop telemetry

Author: Berdeu, A., primary, Bonnet, H., additional, Le Bouquin, J.-B., additional, Édouard, C., additional, Gomes, T., additional, Shchekaturov, P., additional, Dembet, R., additional, Paumard, T., additional, Oberti, S., additional, Kolb, J., additional, Millour, F., additional, Berio, P., additional, Lai, O., additional, Eisenhauer, F., additional, Garcia, P., additional, Straubmeier, C., additional, Kreidberg, L., additional, Hönig, S.F., additional, and Defrère, D., additional
Published: 2024
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4. A magnetic massive star has experienced a stellar merger

Author: Frost, A. J., primary, Sana, H., additional, Mahy, L., additional, Wade, G., additional, Barron, J., additional, Le Bouquin, J.-B., additional, Mérand, A., additional, Schneider, F. R. N., additional, Shenar, T., additional, Barbá, R. H., additional, Bowman, D. M., additional, Fabry, M., additional, Farhang, A., additional, Marchant, P., additional, Morrell, N. I., additional, and Smoker, J. V., additional
Published: 2024
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5. A dusty veil shading Betelgeuse during its Great Dimming

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.
Published: 2021
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6. A new dimension in the variability of AGB stars : Convection patterns size changes with pulsation

Author: Rosales-Guzmán, A., Sanchez-Bermudez, J., Paladini, C., Freytag, Bernd, Wittkowski, M., Alberdi, A., Baron, F., Berger, J. P., Chiavassa, A., Höfner, Susanne, Jorissen, A., Kervella, P., Le Bouquin, J.-B., Marigo, P., Montargès, M., Trabucchi, M., Tsvetkova, S., Schödel, R., Van Eck, S., Rosales-Guzmán, A., Sanchez-Bermudez, J., Paladini, C., Freytag, Bernd, Wittkowski, M., Alberdi, A., Baron, F., Berger, J. P., Chiavassa, A., Höfner, Susanne, Jorissen, A., Kervella, P., Le Bouquin, J.-B., Marigo, P., Montargès, M., Trabucchi, M., Tsvetkova, S., Schödel, R., and Van Eck, S.
Published: 2024
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7. The large-scale magnetic field of the M dwarf double-line spectroscopic binary FK Aqr*

Author: Tsvetkova, S., Morin, J., Folsom, C. P., Le Bouquin, J. -B, Alecian, E., Bellotti, S., Hussain, G., Kochukhov, Oleg, Marsden, S. C., Neiner, C., Petit, P., Wade, G. A., Tsvetkova, S., Morin, J., Folsom, C. P., Le Bouquin, J. -B, Alecian, E., Bellotti, S., Hussain, G., Kochukhov, Oleg, Marsden, S. C., Neiner, C., Petit, P., and Wade, G. A.
Abstract: Context. This work is part of the BinaMIcS project, the aim of which is to understand the interaction between binarity and magnetism in close binary systems. All the studied spectroscopic binaries targeted by the BinaMIcS project encompass hot massive and intermediate-mass stars on the main sequence, as well as cool stars over a wide range of evolutionary stages. Aims. The present paper focuses on the binary system FK Aqr, which is composed of two early M dwarfs. Both stars are already known to be magnetically active based on their light curves and detected flare activity. In addition, the two components have large convective envelopes with masses just above the fully convective limit, making the system an ideal target for studying effect of binarity on stellar dynamos. Methods. We use spectropolarimetric observations obtained with ESPaDOnS at CFHT in September 2014. Mean Stokes I and V line profiles are extracted using the least-squares deconvolution (LSD) method. The radial velocities of the two components are measured from the LSD Stokes I profiles and are combined with interferometric measurements in order to constrain the orbital parameters of the system. The longitudinal magnetic fields B-l and chromospheric activity indicators are measured from the LSD mean line profiles. The rotational modulation of the Stokes V profiles is used to reconstruct the surface magnetic field structures of both stars via the Zeeman Doppler imaging (ZDI) inversion technique. Results. Maps of the surface magnetic field structures of both components of FK Aqr are presented for the first time. Our study shows that both components host similar large-scale magnetic fields of moderate intensity (B-mean similar or equal to 0.25 kG); both are predominantly poloidal and feature a strong axisymmetric dipolar component. Conclusions. Both components of FK Aqr feature a rather strong large-scale magnetic field (compared to single early M dwarfs with similar masses) with a mainly dipolar axisymm
Published: 2024
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8. Using the motion of S2 to constrain vector clouds around SgrA

Author: Foschi, A, primary, Abuter, R, additional, El Dayem, K Abd, additional, Aimar, N, additional, Seoane, P Amaro, additional, Amorim, A, additional, Berger, J P, additional, Bonnet, H, additional, Bourdarot, G, additional, Brandner, W, additional, Davies, R, additional, de Zeeuw, P T, additional, Defrère, D, additional, Dexter, J, additional, Drescher, A, additional, Eckart, A, additional, Eisenhauer, F, additional, Schreiber, N M Förster, additional, Garcia, P J V, additional, Genzel, R, additional, Gillessen, S, additional, Gomes, T, additional, Haubois, X, additional, Heißel, G, additional, Henning, Th, additional, Jochum, L, additional, Jocou, L, additional, Kaufer, A, additional, Kreidberg, L, additional, Lacour, S, additional, Lapeyrère, V, additional, Le Bouquin, J-B, additional, Léna, P, additional, Lutz, D, additional, Mang, F, additional, Millour, F, additional, Ott, T, additional, Paumard, T, additional, Perraut, K, additional, Perrin, G, additional, Pfuhl, O, additional, Rabien, S, additional, Ribeiro, D C, additional, Bordoni, M Sadun, additional, Scheithauer, S, additional, Shangguan, J, additional, Shimizu, T, additional, Stadler, J, additional, Straubmeier, C, additional, Sturm, E, additional, Subroweit, M, additional, Tacconi, L J, additional, Vincent, F, additional, von Fellenberg, S, additional, and Woillez, J, additional
Published: 2024
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9. Estimation of the lateral mis-registrations of the GRAVITY+ adaptive optics system: Perturbative method with open-loop modal correlation and non-perturbative method with temporal correlation of closed-loop telemetry.

Author: Berdeu, A., Bonnet, H., Le Bouquin, J.-B., Édouard, C., Gomes, T., Shchekaturov, P., Dembet, R., Paumard, T., Oberti, S., Kolb, J., Millour, F., Berio, P., Lai, O., Eisenhauer, F., Garcia, P., Straubmeier, C., Kreidberg, L., Hönig, S. F., and Defrère, D.
Subjects: ADAPTIVE optics, TARGET acquisition, NUMERICAL analysis, TELEMETRY, TELESCOPES, WAVEFRONT sensors
Abstract: Context. The GRAVITY+ upgrade implies a complete renewal of its adaptive optics (AO) systems. Its complex design, featuring moving components between the deformable mirrors and the wavefront sensors, requires the monitoring and auto-calibrating of the lateral mis-registrations of the system while in operation. Aims. For preset and target acquisition, large lateral registration errors must be assessed in open loop to bring the system to a state where the AO loop closes. In closed loop, these errors must be monitored and corrected, without impacting the science. Methods. With respect to the first requirement, our method is perturbative, with two-dimensional modes intentionally applied to the system and correlated to a reference interaction matrix. For the second requirement, we applied a non-perturbative approach that searches for specific patterns in temporal correlations in the closed loop telemetry. This signal is produced by the noise propagation through the AO loop. Results. Our methods were validated through simulations and on the GRAVITY+ development bench. The first method robustly estimates the lateral mis-registrations, in a single fit and with a sub-subaperture resolution while in an open loop. The second method is not absolute, but it does successfully bring the system towards a negligible mis-registration error, with a limited turbulence bias. Both methods proved to robustly work on a system still under development and not fully characterised. Conclusions. Tested with Shack-Hartmann wavefront sensors, the proposed methods are versatile and easily adaptable to other AO instruments, such as the pyramid, which stands as a baseline for all future AO systems. The non-perturbative method, not relying on an interaction matrix model and being sparse in the Fourier domain, is particularly suitable to the next generation of AO systems for extremely large telescopes that will present an unprecedented level of complexity and numbers of actuators. [ABSTRACT FROM AUTHOR]
Published: 2024
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10. High Angular Resolution and Young Stellar Objects: Imaging the Surroundings of MWC 158 by Optical Interferometry

Author: Kluska, J., primary, Malbet, F., additional, Berger, J.-P., additional, Benisty, M., additional, Lazareff, B., additional, Le Bouquin, J.-B., additional, and Pinte, C., additional
Published: 2020
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11. Star-disk interactions in the strongly accreting T Tauri star S CrA N

Author: Nowacki, H., primary, Alecian, E., additional, Perraut, K., additional, Zaire, B., additional, Folsom, C. P., additional, Pouilly, K., additional, Bouvier, J., additional, Manick, R., additional, Pantolmos, G., additional, Sousa, A. P., additional, Dougados, C., additional, Hussain, G. A. J, additional, Alencar, S. H. P., additional, and Le Bouquin, J. B., additional
Published: 2023
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12. The path towards high-contrast imaging with the VLTI: the Hi-5 project

Author: Defrère, D., Absil, O., Berger, J.-P., Boulet, T., Danchi, W. C., Ertel, S., Gallenne, A., Hénault, F., Hinz, P., Huby, E., Ireland, M., Kraus, S., Labadie, L., Le Bouquin, J.-B., Martin, G., Matter, A., Mérand, A., Mennesson, B., Minardi, S., Monnier, J. D., Norris, B., de Xivry, G. Orban, Pedretti, E., Pott, J.-U., Reggiani, M., Serabyn, E., Surdej, J., Tristram, K. R. W., and Woillez, J.
Published: 2018
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13. FU Orionis disk outburst: Evidence for a gravitational instability scenario triggered in a magnetically dead zone

Author: Bourdarot, G., primary, Berger, J.-P., additional, Lesur, G., additional, Perraut, K., additional, Malbet, F., additional, Millan-Gabet, R., additional, Le Bouquin, J.-B., additional, Garcia-Lopez, R., additional, Monnier, J. D., additional, Labdon, A., additional, Kraus, S., additional, Labadie, L., additional, and Aarnio, A., additional
Published: 2023
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14. Star-disk interactions in the strongly accreting T Tauri star S CrA N

Author: Nowacki, H., Alecian, E., Perraut, K., Zaire, B., Folsom, C. P., Pouilly, Kim, Bouvier, J., Manick, R., Pantolmos, G., Sousa, A. P., Dougados, C., Hussain, G. A. J., Alencar, S. H. P., Le Bouquin, J. B., Nowacki, H., Alecian, E., Perraut, K., Zaire, B., Folsom, C. P., Pouilly, Kim, Bouvier, J., Manick, R., Pantolmos, G., Sousa, A. P., Dougados, C., Hussain, G. A. J., Alencar, S. H. P., and Le Bouquin, J. B.
Abstract: Context. Classical T Tauri Stars are thought to accrete material from their surrounding protoplanetary disks through funnel flows along their magnetic field lines. Among them, those with high accretion rates (similar to 10(-7)M(circle dot) yr(-1) ) are ideal targets to test this magnetospheric accretion scenario in a sustained regime.Aims. We aimed at constraining the accretion-ejection phenomena around the strongly-accreting Northern component of the S CrA young binary system (S CrA N) by deriving its magnetic field topology and its magnetospheric properties, and by detecting ejection signatures, if any.Methods. We led a two-week observing campaign on S CrA N with the ESPaDOnS optical spectropolarimeter at the Canada-FranceHawaii Telescope. We recorded 12 Stokes I and V spectra over 14 nights. We computed the corresponding Least-Square Deconvolution (LSD) profiles of the photospheric lines and performed Zeeman-Doppler Imaging (ZDI). We analysed the kinematics of noticeable emission lines, namely He I lambda 5876 and the four first lines of the Balmer series, known to trace the accretion process. Results. We found that S CrA N is a low-mass (0.8 M-circle dot), young (similar to 1 Myr), and fully convective object exhibiting a strong and variable veiling (with a mean value of 7 +/- 2), which suggests that the star is in a strong accretion regime. These findings could indicate a stellar evolutionary stage between Class I and Class II for S CrA N. We reconstructed an axisymmetric large-scale magnetic field (similar to 70% of the total energy), primarily located in the dipolar component but with significant higher poloidal orders. From the He I lambda 5876 narrow emission component radial velocity curve, we derived a stellar rotation period of P-& lowast; = 7.3 +/- 0.2 days. We found a magnetic truncation radius of similar to 2 R-& lowast; which is significantly closer to the star than the corotation radius of similar to 6 R-& lowast;, suggesting that S CrA
Published: 2023
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15. Where intermediate-mass black holes could hide in the Galactic Centre:A full parameter study with the S2 orbit

Author: Straub, O., Bauböck, M., Abuter, R., Aimar, N., Seoane, P. Amaro, Amorim, A., Berger, J. P., Bonnet, H., Bourdarot, G., Brandner, W., Cardoso, V., Clénet, Y., Dallilar, Y., Davies, R., De Zeeuw, P. T., Dexter, J., Drescher, A., Eisenhauer, F., Förster Schreiber, N. M., Foschi, A., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heißel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrère, V., Le Bouquin, J.-b., Léna, P., Lutz, D., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Ribeiro, D. C., Bordoni, M. Sadun, Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., Von Fellenberg, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Straub, O., Bauböck, M., Abuter, R., Aimar, N., Seoane, P. Amaro, Amorim, A., Berger, J. P., Bonnet, H., Bourdarot, G., Brandner, W., Cardoso, V., Clénet, Y., Dallilar, Y., Davies, R., De Zeeuw, P. T., Dexter, J., Drescher, A., Eisenhauer, F., Förster Schreiber, N. M., Foschi, A., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heißel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrère, V., Le Bouquin, J.-b., Léna, P., Lutz, D., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Ribeiro, D. C., Bordoni, M. Sadun, Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., Von Fellenberg, S., Widmann, F., Wieprecht, E., Wiezorrek, E., and Woillez, J.
Published: 2023

16. Polarimetry and astrometry of NIR flares as event horizon scale, dynamical probes for the mass of Sgr A*

Author: Abuter, R., Aimar, N., Amaro Seoane, P., Amorim, A., Bauböck, M., Berger, J. P., Bonnet, H., Bourdarot, G., Brandner, W., Cardoso, V., Clénet, Y., Davies, R., De Zeeuw, P. T., Dexter, J., Drescher, A., Eckart, A., Eisenhauer, F., Feuchtgruber, H., Finger, G., Förster Schreiber, N. M., Foschi, A., Garcia, P., Gao, F., Gelles, Z., Gendron, E., Genzel, R., Gillessen, S., Hartl, M., Haubois, X., Haussmann, F., Heißel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrère, V., Le Bouquin, J.-b., Léna, P., Lutz, D., Mang, F., More, N., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Ribeiro, D. C., Sadun Bordoni, M., Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., Von Fellenberg, S., Widmann, F., Wielgus, M., Wieprecht, E., Wiezorrek, E., Woillez, J., Abuter, R., Aimar, N., Amaro Seoane, P., Amorim, A., Bauböck, M., Berger, J. P., Bonnet, H., Bourdarot, G., Brandner, W., Cardoso, V., Clénet, Y., Davies, R., De Zeeuw, P. T., Dexter, J., Drescher, A., Eckart, A., Eisenhauer, F., Feuchtgruber, H., Finger, G., Förster Schreiber, N. M., Foschi, A., Garcia, P., Gao, F., Gelles, Z., Gendron, E., Genzel, R., Gillessen, S., Hartl, M., Haubois, X., Haussmann, F., Heißel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrère, V., Le Bouquin, J.-b., Léna, P., Lutz, D., Mang, F., More, N., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Ribeiro, D. C., Sadun Bordoni, M., Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., Von Fellenberg, S., Widmann, F., Wielgus, M., Wieprecht, E., Wiezorrek, E., and Woillez, J.
Published: 2023

17. Combining HIPPARCOS and Gaia data for the study of binaries: The BINARYS tool

Author: Leclerc, A., primary, Babusiaux, C., additional, Arenou, F., additional, van Leeuwen, F., additional, Bonnefoy, M., additional, Delfosse, X., additional, Forveille, T., additional, Le Bouquin, J.-B., additional, and Rodet, L., additional
Published: 2023
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18. Multiplicity of northern bright O-type stars with optical long baseline interferometry

Author: Lanthermann, C., Le Bouquin, J.-B., Sana, H., Mérand, A., Monnier, J. D., Perraut, K., Frost, A. J., Mahy, L., Gosset, E., De Becker, M., Kraus, S., Anugu, N., Davies, C. L., Ennis, J., Gardner, T., Labdon, A., Setterholm, B., ten Brummelaar, T., and Schaefer, G. H.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The study of the multiplicity of massive stars gives hints on their formation processes and their evolutionary paths, which are still not fully understood. Large separation binaries (>50 milliseconds of arc, mas) can be probed by adaptive-optics-assisted direct imaging and sparse aperture masking, while close binaries can be resolved by photometry and spectroscopy. However, optical long baseline interferometry is mandatory to establish the multiplicity of Galactic massive stars at the separation gap between 1 and 50 mas. In this paper, we aim to demonstrate the capability of the new interferometric instrument MIRC-X, located at the CHARA Array, to study the multiplicity of O-type stars and therefore probe the full range of separation for more than 120 massive stars (H, 15 pages, 9 figures, 5 tables, accepted in A&A
Published: 2023
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19. Multiplicity of northern bright O-type stars with optical long baseline interferometry

Author: Lanthermann, C., primary, Le Bouquin, J.-B., additional, Sana, H., additional, Mérand, A., additional, Monnier, J. D., additional, Perraut, K., additional, Frost, A. J., additional, Mahy, L., additional, Gosset, E., additional, De Becker, M., additional, Kraus, S., additional, Anugu, N., additional, Davies, C. L., additional, Ennis, J., additional, Gardner, T., additional, Labdon, A., additional, Setterholm, B., additional, ten Brummelaar, T., additional, and Schaefer, G. H., additional
Published: 2023
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20. Direct discovery of the inner exoplanet in the HD 206893 system

Author: Hinkley, S., primary, Lacour, S., additional, Marleau, G.-D., additional, Lagrange, A.-M., additional, Wang, J. J., additional, Kammerer, J., additional, Cumming, A., additional, Nowak, M., additional, Rodet, L., additional, Stolker, T., additional, Balmer, W.-O., additional, Ray, S., additional, Bonnefoy, M., additional, Mollière, P., additional, Lazzoni, C., additional, Kennedy, G., additional, Mordasini, C., additional, Abuter, R., additional, Aigrain, S., additional, Amorim, A., additional, Asensio-Torres, R., additional, Babusiaux, C., additional, Benisty, M., additional, Berger, J.-P., additional, Beust, H., additional, Blunt, S., additional, Boccaletti, A., additional, Bohn, A., additional, Bonnet, H., additional, Bourdarot, G., additional, Brandner, W., additional, Cantalloube, F., additional, Caselli, P., additional, Charnay, B., additional, Chauvin, G., additional, Chomez, A., additional, Choquet, E., additional, Christiaens, V., additional, Clénet, Y., additional, Coudé du Foresto, V., additional, Cridland, A., additional, Delorme, P., additional, Dembet, R., additional, Drescher, A., additional, Duvert, G., additional, Eckart, A., additional, Eisenhauer, F., additional, Feuchtgruber, H., additional, Galland, F., additional, Garcia, P., additional, Garcia Lopez, R., additional, Gardner, T., additional, Gendron, E., additional, Genzel, R., additional, Gillessen, S., additional, Girard, J. H., additional, Grandjean, A., additional, Haubois, X., additional, Heißel, G., additional, Henning, Th., additional, Hippler, S., additional, Horrobin, M., additional, Houllé, M., additional, Hubert, Z., additional, Jocou, L., additional, Keppler, M., additional, Kervella, P., additional, Kreidberg, L., additional, Lapeyrère, V., additional, Le Bouquin, J.-B., additional, Léna, P., additional, Lutz, D., additional, Maire, A.-L., additional, Mang, F., additional, Mérand, A., additional, Meunier, N., additional, Monnier, J. D., additional, Mouillet, D., additional, Nasedkin, E., additional, Ott, T., additional, Otten, G. P. P. L., additional, Paladini, C., additional, Paumard, T., additional, Perraut, K., additional, Perrin, G., additional, Philipot, F., additional, Pfuhl, O., additional, Pourré, N., additional, Pueyo, L., additional, Rameau, J., additional, Rickman, E., additional, Rubini, P., additional, Rustamkulov, Z., additional, Samland, M., additional, Shangguan, J., additional, Shimizu, T., additional, Sing, D., additional, Straubmeier, C., additional, Sturm, E., additional, Tacconi, L. J., additional, van Dishoeck, E. F., additional, Vigan, A., additional, Vincent, F., additional, Ward-Duong, K., additional, Widmann, F., additional, Wieprecht, E., additional, Wiezorrek, E., additional, Woillez, J., additional, Yazici, S., additional, Young, A., additional, and Zicher, N., additional
Published: 2023
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21. 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, J., Neuhäuser, R., Kern, P., Jocou, L., Berger, J.-P., 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, O., Chiavassa, A., Corradi, R., de Becker, M., Delboulbé, A., Duchêne, G., Forveille, T., Haniff, C., Herwats, E., Hofmann, K.-H., Le Bouquin, J.-B., Ligori, S., Loreggia, D., Marconi, A., Moitinho, A., Nisini, B., Petrucci, P.-O., Rebordao, J., Speziali, R., Testi, L., Vitali, F., Burton, W. B., editor, Christensen, Lars Lindberg, editor, and Moorwood, Alan, editor
Published: 2009
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22. Hi-5: A Potential High-Contrast Thermal Near-Infrared Imager for the VLTI

Author: Defrere, D, Ireland, M, Absil, O, Berger, J.-P, Danchi, W.C, Ertel, S, Gallenne, A, Henault, F, Hinz, P, Huby, E, Kraus, S, Labadie, L, Le Bouquin, J.-B, Martin, G, Matter, A, Mennesson, B, Merand, A, Minardi, S, Monnier, J. D, Norris, B, Orban de Xivry, G, Pedretti, E, Pott, J.-U, Reggiani, M, Serabyn, E, Surdej, J, Tristram, K. R. W, and Woillez, J
Subjects: Astrophysics
Abstract: Hi-5 is a high-contrast (or high dynamic range) infrared imager project for the VLTI. Its main goal is to characterize young extra-solar planetary systems and exozodiacal dust around southern main-sequence stars. In this paper, we present an update of the project and key technology pathways to improve the contrast achieved by the VLTI. In particular, we discuss the possibility to use integrated optics, proven in the near-infrared, in the thermal near-infrared (L and M bands, 3-5 μm) and advanced fringe tracking strategies. We also address the strong exoplanet science case (young exoplanets, planet formation, and exozodiacal disks) offered by this wavelength regime as well as other possible science cases such as stellar physics (fundamental parameters and multiplicity) and extragalactic astrophysics (active galactic nuclei and fundamental constants). Synergies and scientific preparation for other potential future instruments such as the Planet Formation Imager are also briefly discussed.
Published: 2018
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23. Binary Interaction Dominates the Evolution of Massive Stars

Author: Sana, H., de Mink, S. E., de Koter, A., Langer, N., Evans, C. J., Gieles, M., Gosset, E., Izzard, R. G., Le Bouquin, J.-B., and Schneider, F. R. N.
Published: 2012
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24. Low-wind-effect impact on Shack-Hartmann-based adaptive optics

Author: Pourré, N., primary, Le Bouquin, J.-B., additional, Milli, J., additional, Sauvage, J.-F., additional, Fusco, T., additional, Correia, C., additional, and Oberti, S., additional
Published: 2022
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25. A detailed analysis of the Gl 486 planetary system

Author: Caballero, J. A., primary, González-Álvarez, E., additional, Brady, M., additional, Trifonov, T., additional, Ellis, T. G., additional, Dorn, C., additional, Cifuentes, C., additional, Molaverdikhani, K., additional, Bean, J. L., additional, Boyajian, T., additional, Rodríguez, E., additional, Sanz-Forcada, J., additional, Zapatero Osorio, M. R., additional, Abia, C., additional, Amado, P. J., additional, Anugu, N., additional, Béjar, V. J. S., additional, Davies, C. L., additional, Dreizler, S., additional, Dubois, F., additional, Ennis, J., additional, Espinoza, N., additional, Farrington, C. D., additional, López, A. García, additional, Gardner, T., additional, Hatzes, A. P., additional, Henning, Th., additional, Herrero, E., additional, Herrero-Cisneros, E., additional, Kaminski, A., additional, Kasper, D., additional, Klement, R., additional, Kraus, S., additional, Labdon, A., additional, Lanthermann, C., additional, Le Bouquin, J.-B., additional, González, M. J. López, additional, Luque, R., additional, Mann, A. W., additional, Marfil, E., additional, Monnier, J. D., additional, Montes, D., additional, Morales, J. C., additional, Pallé, E., additional, Pedraz, S., additional, Quirrenbach, A., additional, Reffert, S., additional, Reiners, A., additional, Ribas, I., additional, Rodríguez-López, C., additional, Schaefer, G., additional, Schweitzer, A., additional, Seifahrt, A., additional, Setterholm, B. R., additional, Shan, Y., additional, Shulyak, D., additional, Solano, E., additional, Sreenivas, K. R., additional, Stefánsson, G., additional, Stürmer, J., additional, Tabernero, H. M., additional, Tal-Or, L., additional, ten Brummelaar, T., additional, Vanaverbeke, S., additional, von Braun, K., additional, Youngblood, A., additional, and Zechmeister, M., additional
Published: 2022
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26. First light for GRAVITY Wide Large separation fringe tracking for the Very Large Telescope Interferometer

Author: Abuter, R., Allouche, F., Amorim, A., Bailet, C., Bauboeck, M., Berger, J-P, Berio, P., Bigioli, A., Boebion, O., Bolzer, M. L., Bonnet, H., Bourdarot, G., Bourget, P., Brandner, W., Clenet, Y., Courtney-Barrer, B., Dallilar, Y., Davies, R., Defrere, D., Delboulbe, A., Delplancke, F., Dembet, R., de Zeeuw, P. T., Drescher, A., Eckart, A., Edouard, C., Eisenhauer, F., Fabricius, M., Feuchtgruber, H., Finger, G., Schreiber, N. M. Foerster, Garcia, E., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gil, J. P., Gillessen, S., Gomes, T., Gonte, F., Gouvret, C., Guajardo, P., Guieu, S., Hartl, M., Haubois, X., Haussmann, F., Heissel, G., Henning, Th, Hippler, S., Honig, S., Horrobin, M., Hubin, N., Jacqmart, E., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Korhonen, H., Kreidberg, L., Lacour, S., Lagarde, S., Lai, O., Lapeyrere, V, Laugier, R., Le Bouquin, J-B, Leftley, J., Lena, P., Lutz, D., Mang, F., Marcotto, A., Maurel, D., Merand, A., Millour, F., More, N., Nowacki, H., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Paumard, T., Perraut, K., Perrin, G., Petrov, R., Pfuhl, O., Pourre, N., Rabien, S., Rau, C., Robbe-Dubois, S., Rochat, S., Salman, M., Scholler, M., Schubert, J., Schuhler, N., Shangguan, J., Shimizu, T., Scheithauer, S., Sevin, A., Soulez, F., Spang, A., Stadler, E., Stadler, J., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Uysal, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., Zins, G., Abuter, R., Allouche, F., Amorim, A., Bailet, C., Bauboeck, M., Berger, J-P, Berio, P., Bigioli, A., Boebion, O., Bolzer, M. L., Bonnet, H., Bourdarot, G., Bourget, P., Brandner, W., Clenet, Y., Courtney-Barrer, B., Dallilar, Y., Davies, R., Defrere, D., Delboulbe, A., Delplancke, F., Dembet, R., de Zeeuw, P. T., Drescher, A., Eckart, A., Edouard, C., Eisenhauer, F., Fabricius, M., Feuchtgruber, H., Finger, G., Schreiber, N. M. Foerster, Garcia, E., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gil, J. P., Gillessen, S., Gomes, T., Gonte, F., Gouvret, C., Guajardo, P., Guieu, S., Hartl, M., Haubois, X., Haussmann, F., Heissel, G., Henning, Th, Hippler, S., Honig, S., Horrobin, M., Hubin, N., Jacqmart, E., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Korhonen, H., Kreidberg, L., Lacour, S., Lagarde, S., Lai, O., Lapeyrere, V, Laugier, R., Le Bouquin, J-B, Leftley, J., Lena, P., Lutz, D., Mang, F., Marcotto, A., Maurel, D., Merand, A., Millour, F., More, N., Nowacki, H., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Paumard, T., Perraut, K., Perrin, G., Petrov, R., Pfuhl, O., Pourre, N., Rabien, S., Rau, C., Robbe-Dubois, S., Rochat, S., Salman, M., Scholler, M., Schubert, J., Schuhler, N., Shangguan, J., Shimizu, T., Scheithauer, S., Sevin, A., Soulez, F., Spang, A., Stadler, E., Stadler, J., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Uysal, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., and Zins, G.
Abstract: GRAVITY+ is the upgrade for GRAVITY and the Very Large Telescope Interferometer (VLTI) with wide-separation fringe tracking, new adaptive optics, and laser guide stars on all four 8 m Unit Telescopes (UTs) to enable ever-fainter, all-sky, high-contrast, milliarcsecond interferometry. Here we present the design and first results of the first phase of GRAVITY+, known as GRAVITY Wide. GRAVITY Wide combines the dual-beam capabilities of the VLTI and the GRAVITY instrument to increase the maximum separation between the science target and the reference star from 2 arcseconds with the 8 m UTs up to several 10 arcseconds, limited only by the Earth's turbulent atmosphere. This increases the sky-coverage of GRAVITY by two orders of magnitude, opening up milliarcsecond resolution observations of faint objects and, in particular, the extragalactic sky. The first observations in 2019-2022 include the first infrared interferometry of two redshift z similar to 2 quasars, interferometric imaging of the binary system HD 105913A, and repeat observations of multiple star systems in the Orion Trapezium Cluster. We find the coherence loss between the science object and fringe-tracking reference star well described by the turbulence of the Earth's atmosphere. We confirm that the larger apertures of the UTs result in higher visibilities for a given separation due to the broader overlap of the projected pupils on the sky and provide predictions for visibility loss as a function of separation to be used for future planning.
Published: 2022

27. Deep images of the Galactic center with GRAVITY

Author: Abuter, R., Aimar, N., Amorim, A., Arras, P., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Bourdarot, G., Cardoso, V, Clenet, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Dallilar, Y., Drescher, A., Eisenhauer, F., Ensslin, T., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Mang, F., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Waisberg, I, Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., Zins, G., Abuter, R., Aimar, N., Amorim, A., Arras, P., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Bourdarot, G., Cardoso, V, Clenet, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Dallilar, Y., Drescher, A., Eisenhauer, F., Ensslin, T., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Mang, F., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Waisberg, I, Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., and Zins, G.
Abstract: Stellar orbits at the Galactic Center provide a very clean probe of the gravitational potential of the supermassive black hole. They can be studied with unique precision, beyond the confusion limit of a single telescope, with the near-infrared interferometer GRAVITY. Imaging is essential to search the field for faint, unknown stars on short orbits which potentially could constrain the black hole spin. Furthermore, it provides the starting point for astrometric fitting to derive highly accurate stellar positions. Here, we present G(R), a new imaging tool specifically designed for Galactic Center observations with GRAVITY. The algorithm is based on a Bayesian interpretation of the imaging problem, formulated in the framework of information field theory and building upon existing works in radio-interferometric imaging. Its application to GRAVITY observations from 2021 yields the deepest images to date of the Galactic Center on scales of a few milliarcseconds. The images reveal the complicated source structure within the central 100mas around Sgr A*, where we detected the stars S29 and S55 and confirm S62 on its trajectory, slowly approaching Sgr A*. Furthermore, we were able to detect S38, S42, S60, and S63 in a series of exposures for which we offset the fiber from Sgr A*. We provide an update on the orbits of all aforementioned stars. In addition to these known sources, the images also reveal a faint star moving to the west at a high angular velocity. We cannot find any coincidence with any known source and, thus, we refer to the new star as S300. From the flux ratio with S29, we estimate its K-band magnitude as m(K)(S300)similar or equal to 19.0 - 19.3. Images obtained with CLEAN confirm the detection. To assess the sensitivity of our images, we note that fiber damping reduces the apparent magnitude of S300 and the effect increases throughout the year as the star moves away from the field center. Furthermore, we performed a series of source injection tests. Under fa
Published: 2022

28. Mass distribution in the Galactic Center based on interferometric astrometry of multiple stellar orbits

Author: Abuter, R., Aimar, N., Amorim, A., Ball, J., Bauboeck, M., Berger, J. P., Bonnet, H., Bourdarot, G., Brandner, W., Cardoso, V, Clenet, Y., Dallilar, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Drescher, A., Eisenhauer, F., Schreiber, N. M. Foerster, Foschi, A., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Stephens, A. W., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., Abuter, R., Aimar, N., Amorim, A., Ball, J., Bauboeck, M., Berger, J. P., Bonnet, H., Bourdarot, G., Brandner, W., Cardoso, V, Clenet, Y., Dallilar, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Drescher, A., Eisenhauer, F., Schreiber, N. M. Foerster, Foschi, A., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Stephens, A. W., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., and Young, A.
Abstract: Stars orbiting the compact radio source Sgr A* in the Galactic Center serve as precision probes of the gravitational field around the closest massive black hole. In addition to adaptive optics-assisted astrometry (with NACO/VLT) and spectroscopy (with SINFONI/VLT, NIRC2/Keck and GNIRS/Gemini) over three decades, we have obtained 30-100 mu as astrometry since 2017 with the four-telescope interferometric beam combiner GRAVITY/VLTI, capable of reaching a sensitivity of m(K)=20 when combining data from one night. We present the simultaneous detection of several stars within the diffraction limit of a single telescope, illustrating the power of interferometry in the field. The new data for the stars S2, S29, S38, and S55 yield significant accelerations between March and July 2021, as these stars pass the pericenters of their orbits between 2018 and 2023. This allows for a high-precision determination of the gravitational potential around Sgr A*. Our data are in excellent agreement with general relativity orbits around a single central point mass, M-center dot=4.30 x 10(6)M(circle dot), with a precision of about +/- 0.25%. We improve the significance of our detection of the Schwarzschild precession in the S2 orbit to 7 sigma. Assuming plausible density profiles, the extended mass component inside the S2 apocenter (approximate to 0.23 '' or 2.4 x 10(4)R(S)) must be less than or similar to 3000M(circle dot)(1 sigma), or less than or similar to 0.1% of M-center dot. Adding the enclosed mass determinations from 13 stars orbiting Sgr A* at larger radii, the innermost radius at which the excess mass beyond Sgr A* is tentatively seen is r approximate to 2.5 ''>= 10x the apocenter of S2. This is in full harmony with the stellar mass distribution (including stellar-mass black holes) obtained from the spatially resolved luminosity function.
Published: 2022

29. Probing the low-mass end of the companion mass function for O-type stars

Author: Reggiani, M., primary, Rainot, A., additional, Sana, H., additional, Almeida, L. A., additional, Caballero-Nieves, S., additional, Kratter, K., additional, Lacour, S., additional, Le Bouquin, J.-B., additional, and Zinnecker, H., additional
Published: 2022
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30. First light for GRAVITY Wide

Author: Abuter, R., Allouche, F., Amorim, A., Bailet, C., Bauböck, M., Berger, J.-P., Berio, P., Bigioli, A., Boebion, O., Bolzer, M.L., Bonnet, H., Bourdarot, G., Bourget, P., Brandner, W., Clénet, Y., Courtney-Barrer, B., Dallilar, Y., Davies, R., Defrère, D., Delboulbé, A., Delplancke, F., Dembet, R., Zeeuw, P.T. de, Drescher, A., Eckart, A., Édouard, C., Eisenhauer, F., Fabricius, M., Feuchtgruber, H., Finger, G., Förster Schreiber, N.M., Garcia, E., Garcia, P., Gao, F., Gendron, E., Genzel, R., Gil, J.P., Gillessen, S., Gomes, T., Gonté, F., Gouvret, C., Guajardo, P., Guieu, S., Hartl, M., Haubois, X., Haußmann, F., Heißel, G., Henning, T., Hippler, S., Hönig, S., Horrobin, M., Hubin, N., Jacqmart, E., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Korhonen, H., Kreidberg, L., Lacour, S., Lagarde, S., Lai, O., Lapeyrère, V., Laugier, R., Le Bouquin, J.-B., Leftley, J., Léna, P., Lutz, D., Mang, F., Marcotto, A., Maurel, D., Mérand, A., Millour, F., More, N., Nowacki, H., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Pasquini, L., Paumard, T., Perraut, K., Perrin, G., Petrov, R., Pfuhl, O., Pourré, N., Rabien, S., Rau, C., Robbe-Dubois, S., Rochat, S., Salman, M., Schöller, M., Schubert, J., Schuhler, N., Shangguan, J., Shimizu, T., Scheithauer, S., Sevin, A., Soulez, F., Spang, A., Stadler, E., Stadler, J., Straubmeier, C., Sturm, E., Tacconi, L.J., Tristram, K.R.W., Vincent, F., von Fellenberg, S., Uysal, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., and Zins, G.
Subjects: Instrumentation - high angular resolution, Astrophysics - instrumentation and methods for astrophysics, interferometers [instrumentation], FOS: Physical sciences, GAIA, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Stars: individual - Orion Trapezium Cluster, Instrumentation - interferometers, HISTORY, ORION TRAPEZIUM STARS, Astrophysics::Solar and Stellar Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, Science & Technology, supermassive black holes [quasars], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, individual: Orion Trapezium Cluster [stars], ORBIT, ANGLE, LONG, Quasars - supermassive black holes, Space and Planetary Science, ANISOPLANATISM, Physical Sciences, Astrophysics::Earth and Planetary Astrophysics, high angular resolution [instrumentation]
Abstract: GRAVITY+ is the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) with wide-separation fringe tracking, new adaptive optics, and laser guide stars on all four 8~m Unit Telescopes (UTs), for ever fainter, all-sky, high contrast, milliarcsecond interferometry. Here we present the design and first results of the first phase of GRAVITY+, called GRAVITY Wide. GRAVITY Wide combines the dual-beam capabilities of the VLTI and the GRAVITY instrument to increase the maximum separation between the science target and the reference star from 2 arcseconds with the 8 m UTs up to several 10 arcseconds, limited only by the Earth's turbulent atmosphere. This increases the sky-coverage of GRAVITY by two orders of magnitude, opening up milliarcsecond resolution observations of faint objects, and in particular the extragalactic sky. The first observations in 2019 - 2022 include first infrared interferometry of two redshift $z\sim2$ quasars, interferometric imaging on the binary system HD 105913A, and repeated observations of multiple star systems in the Orion Trapezium Cluster. We find the coherence loss between the science object and fringe-tracking reference star well described by the turbulence of the Earth's atmosphere. We confirm that the larger apertures of the UTs result in higher visibilities for a given separation due to larger overlap of the projected pupils on sky and give predictions for visibility loss as a function of separation to be used for future planning., Comment: 15 pages, 12 figures, 5 tables. Accepted by A&A
Published: 2022
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31. Characterizing the morphology of the debris disk around the low-mass star GSC 07396-00759

Author: Lacour, S., Wang, J., Rodet, L., Nowak, M., Shangguan, J., Beust, H., Lagrange, A.-M., Abuter, R., Amorim, A., Asensio-Torres, R., Benisty, M., Berger, J.-P., Blunt, S., Boccaletti, A., Bohn, A., Bolzer, M.-L., Bonnefoy, M., BONNET, H., Bourdarot, G., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V., Clénet, Y., Coudé Du Foresto, V., Cridland, A., Dembet, R., Dexter, J., de Zeeuw, P., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Gao, F., Garcia, P., Garcia Lopez, R., Gendron, E., Genzel, R., Gillessen, S., Girard, J., Haubois, X., Heißel, G., Henning, Th., Hinkley, S., Hippler, S., Horrobin, M., Houllé, M., Hubert, Z., Jocou, L., Kammerer, J., Keppler, M., Kervella, P., Kreidberg, L., Lapeyrère, V., Le Bouquin, J.-B., Léna, P., Lutz, D., Maire, A.-L., Mérand, A., Mollière, P., Monnier, J., Mouillet, D., Nasedkin, E., Ott, T., Otten, G., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rickman, E., Pueyo, L., Rameau, J., Rousset, G., Rustamkulov, Z., Samland, M., Shimizu, T., Sing, D., Stadler, J., Stolker, T., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L., Van Dishoeck, E., Vigan, A., Vincent, F., Von fellenberg, S., Ward-Duong, K., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., Adam, C., Olofsson, J., van Holstein, R., Bayo, A., Milli, J., Kral, Q., Ginski, C., Montesinos, M., Pawellek, N., Zurlo, A., Langlois, M., Delboulbé, A., Pavlov, A., Ramos, J., Weber, L., Wildi, F., Rigal, F., Sauvage, J.-F., Pawellek, Nicole [0000-0002-9385-9820], Apollo - University of Cambridge Repository, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Low Energy Astrophysics (API, FNWI), and Faculteit der Geesteswetenschappen
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Outflows, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, circumstellar matter, techniques: photometric, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Debris disk, stars: winds, outflows, techniques: high angular resolution, Astronomy and Astrophysics, Radius, Stars: winds, Grain size, Stars, stars: individual: GSC 07396-00759, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, radiative transfer, Scattering theory, Astrophysics::Earth and Planetary Astrophysics, Low Mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Debris disks have commonly been studied around intermediate-mass stars. Their intense radiation fields are believed to efficiently remove the small dust grains that are constantly replenished by collisions. For lower-mass stars, in particular M-stars, the dust removal mechanism needs to be further investigated given the much weaker radiation field produced by these objects. Aims. We present new polarimetric observations of the nearly edge-on disk around the pre-main sequence M-type star GSC 07396-00759, taken with VLT/SPHERE IRDIS, with the aim to better understand the morphology of the disk, its dust properties, and the star-disk interaction via the stellar mass-loss rate. Methods. We model our observations to characterize the location and properties of the dust grains using the Henyey-Greenstein approximation of the polarized phase function and evaluate the strength of the stellar winds. Results. We find that the observations are best described by an extended and highly inclined disk ($i\approx 84.3\,^{\circ}\pm0.3$) with a dust distribution centered at a radius $r_{0}\approx107\pm2$ au. The polarized phase function $S_{12}$ is best reproduced by an anisotropic scattering factor $g\approx0.6$ and small micron-sized dust grains with sizes $s>0.3\,\mathrm��$m. We furthermore discuss some of the caveats of the approach and a degeneracy between the grain size and the porosity. Conclusions. Even though the radius of the disk may be over-estimated, our results suggest that using a given scattering theory might not be sufficient to fully explain key aspects such as the shape of the phase function, or the dust grain size. With the caveats in mind, we find that the average mass-loss rate of GSC 07396-00759 can be up to 500 times stronger than that of the Sun, supporting the idea that stellar winds from low-mass stars can evacuate small dust grains from the disk., 22 pages, 17 figures, 4 tables
Published: 2021
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32. Brown dwarf or exoplanet

Author: Kammerer, J., Lacour, S., Stolker, T., Mollière, P., Sing, D., Nasedkin, E., Kervella, P., Wang, J., Ward-Duong, K., Nowak, M., Abuter, R., Amorim, A., Asensio-Torres, R., Bauböck, M., Benisty, M., Berger, J.-P., Beust, H., Blunt, S., Boccaletti, A., Bohn, A., Bolzer, M.-L., Bonnefoy, M., BONNET, H., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V., Clénet, Y., Coudé Du Foresto, V., Cridland, A., Dembet, R., Dexter, J., de Zeeuw, P., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Gao, F., Garcia, P., Garcia Lopez, R., Gendron, E., Genzel, R., Gillessen, S., Girard, J., Haubois, X., Heißel, G., Henning, T., Hinkley, S., Hippler, S., Horrobin, M., Houllé, M., Hubert, Z., Jocou, L., Keppler, M., Kreidberg, L., Lagrange, A.-M., Lapeyrère, V., Le Bouquin, J.-B., Léna, P., Lutz, D., Maire, A.-L., Mérand, A., Monnier, J., Mouillet, D., Müller, A., Ott, T., Otten, G., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Pueyo, L., Rameau, J., Rodet, L., Rousset, G., Rustamkulov, Z., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L., Van Dishoeck, E., Vigan, A., Vincent, F., Von fellenberg, S., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., European Southern Observatory (ESO), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut 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), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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)-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), and 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)
Subjects: [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU]Sciences of the Universe [physics]
Abstract: International audience; Context. Near-infrared interferometry has become a powerful tool for studying the orbital and atmospheric parameters of substellar companions. Aims. We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion. Methods. We fit atmospheric models for giant planets and brown dwarfs and perform spectral retrievals with petitRADTRANS and ATMO on the observed GRAVITY, SPHERE, and GPI spectra of HD 206893 B. To recover its unusual spectral features, first and foremost its extremely red near-infrared color, we include additional extinction by high-altitude dust clouds made of enstatite grains in the atmospheric model fits. However, forsterite, corundum, and iron grains predict similar extinction curves for the grain sizes considered here. We also infer the orbital parameters of HD 206893 B by combining the ~100 μas precision astrometry from GRAVITY with data from the literature and constrain the mass and position of HD 206893 C based on the Gaia proper motion anomaly of the system. Results. The extremely red color and the very shallow 1.4 μm water absorption feature of HD 206893 B can be fit well with the adapted atmospheric models and spectral retrievals. By comparison with AMES-Cond evolutionary tracks, we find that only some atmosphericmodels predict physically plausible objects. Altogether, our analysis suggests an age of ~ 3–300 Myr and a mass of ~ 5–30 M Jup for HD 206893 B, which is consistent with previous estimates but extends the parameter space to younger and lower-mass objects. The GRAVITY astrometry points to an eccentric orbit ( e = 0.29 −0.11 +0.06 ) with a mutual inclination of
Published: 2021
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33. Refined fundamental parameters of Canopus from combined near-IR interferometry and spectral energy distribution

Author: Domiciano de Souza, A., primary, Zorec, J., additional, Millour, F., additional, Le Bouquin, J.-B., additional, Spang, A., additional, and Vakili, F., additional
Published: 2021
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34. Imaging the heart of astrophysical objects with optical long-baseline interferometry

Author: Berger, J.-P., Malbet, F., Baron, F., Chiavassa, A., Duvert, G., Elitzur, M., Freytag, B., Gueth, F., Hönig, S., Hron, J., Jang-Condell, H., Le Bouquin, J.-B., Monin, J.-L., Monnier, J. D., Perrin, G., Plez, B., Ratzka, T., Renard, S., Stefl, S., Thiébaut, E., Tristram, K. R. W., Verhoelst, T., Wolf, S., and Young, J.
Published: 2012
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35. The GRAVITY young stellar object survey

Author: Koutoulaki, M., Garcia Lopez, R., Natta, A., Fedriani, R., Caratti o Garatti, A., Ray, T. P., Coffey, D., Brandner, W., Dougados, C., Garcia, P. J. V., Klarmann, L., Labadie, L., Perraut, K., Sanchez-Bermudez, J., Lin, C.-C., Amorim, A., Bauböck, M., Benisty, M., Berger, J. P., Buron, A., Caselli, P., Clénet, Y., Coudé du Foresto, V., de Zeeuw, P. T., Duvert, G., de Wit, W., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Habibi, M., Haubois, X., Haussmann, F., Henning, T., Hippler, S., Hubert, Z., Horrobin, M., Jimenez Rosales, A., Jocou, L., Kervella, P., Kolb, J., Lacour, S., Le Bouquin, J.-B., Léna, P., Linz, H., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Ramírez-Tannus, M. C., Rau, C., Rousset, G., Scheithauer, S., Shangguan, J., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Yazici, S., Zins, G., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
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::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: International audience; Context. 51 Oph is a Herbig Ae/Be star that exhibits strong near-infrared CO ro-vibrational emission at 2.3 μ m, most likely originating in the innermost regions of a circumstellar disc. Aims. We aim to obtain the physical and geometrical properties of the system by spatially resolving the circumstellar environment of the inner gaseous disc. Methods. We used the second-generation Very Large Telescope Interferometer instrument GRAVITY to spatially resolve the continuum and the CO overtone emission. We obtained data over 12 baselines with the auxiliary telescopes and derive visibilities, and the differential and closure phases as a function of wavelength. We used a simple local thermal equilibrium ring model of the CO emission to reproduce the spectrum and CO line displacements. Results. Our interferometric data show that the star is marginally resolved at our spatial resolution, with a radius of ~10.58 ± 2.65 R ⊙ . The K -band continuum emission from the disc is inclined by 63° ± 1°, with a position angle of 116° ± 1°, and 4 ± 0.8 mas (0.5 ± 0.1 au) across. The visibilities increase within the CO line emission, indicating that the CO is emitted within the dust-sublimation radius. By modelling the CO bandhead spectrum, we derive that the CO is emitted from a hot ( T = 1900–2800 K) and dense ( N CO = (0.9–9) × 10 21 cm −2 ) gas. The analysis of the CO line displacement with respect to the continuum allows us to infer that the CO is emitted from a region 0.10 ± 0.02 au across, well within the dust-sublimation radius. The inclination and position angle of the CO line emitting region is consistent with that of the dusty disc. Conclusions. Our spatially resolved interferometric observations confirm the CO ro-vibrational emission within the dust-free region of the inner disc. Conventional disc models exclude the presence of CO in the dust-depleted regions of Herbig AeBe stars. Ad hoc models of the innermost disc regions, that can compute the properties of the dust-free inner disc, are therefore required.
Published: 2021
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36. GRAVITY K-band spectroscopy of HD 206893 B

Author: Kammerer, J., primary, Lacour, S., additional, Stolker, T., additional, Mollière, P., additional, Sing, D. K., additional, Nasedkin, E., additional, Kervella, P., additional, Wang, J. J., additional, Ward-Duong, K., additional, Nowak, M., additional, Abuter, R., additional, Amorim, A., additional, Asensio-Torres, R., additional, Bauböck, M., additional, Benisty, M., additional, Berger, J.-P., additional, Beust, H., additional, Blunt, S., additional, Boccaletti, A., additional, Bohn, A., additional, Bolzer, M.-L., additional, Bonnefoy, M., additional, Bonnet, H., additional, Brandner, W., additional, Cantalloube, F., additional, Caselli, P., additional, Charnay, B., additional, Chauvin, G., additional, Choquet, E., additional, Christiaens, V., additional, Clénet, Y., additional, Coudé du Foresto, V., additional, Cridland, A., additional, Dembet, R., additional, Dexter, J., additional, de Zeeuw, P. T., additional, Drescher, A., additional, Duvert, G., additional, Eckart, A., additional, Eisenhauer, F., additional, Gao, F., additional, Garcia, P., additional, Garcia Lopez, R., additional, Gendron, E., additional, Genzel, R., additional, Gillessen, S., additional, Girard, J., additional, Haubois, X., additional, Heißel, G., additional, Henning, T., additional, Hinkley, S., additional, Hippler, S., additional, Horrobin, M., additional, Houllé, M., additional, Hubert, Z., additional, Jocou, L., additional, Keppler, M., additional, Kreidberg, L., additional, Lagrange, A.-M., additional, Lapeyrère, V., additional, Le Bouquin, J.-B., additional, Léna, P., additional, Lutz, D., additional, Maire, A.-L., additional, Mérand, A., additional, Monnier, J. D., additional, Mouillet, D., additional, Müller, A., additional, Ott, T., additional, Otten, G. P. P. L., additional, Paladini, C., additional, Paumard, T., additional, Perraut, K., additional, Perrin, G., additional, Pfuhl, O., additional, Pueyo, L., additional, Rameau, J., additional, Rodet, L., additional, Rousset, G., additional, Rustamkulov, Z., additional, Shangguan, J., additional, Shimizu, T., additional, Stadler, J., additional, Straub, O., additional, Straubmeier, C., additional, Sturm, E., additional, Tacconi, L. J., additional, van Dishoeck, E. F., additional, Vigan, A., additional, Vincent, F., additional, von Fellenberg, S. D., additional, Widmann, F., additional, Wieprecht, E., additional, Wiezorrek, E., additional, Woillez, J., additional, and Yazici, S., additional
Published: 2021
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37. Resolving the dynamical mass tension of the massive binary 9 Sagittarii

Author: Fabry, M., primary, Hawcroft, C., additional, Frost, A. J., additional, Mahy, L., additional, Marchant, P., additional, Le Bouquin, J.-B., additional, and Sana, H., additional
Published: 2021
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38. A near-infrared interferometric survey of debris-disk stars

Author: Absil, O., primary, Marion, L., additional, Ertel, S., additional, Defrère, D., additional, Kennedy, G. M., additional, Romagnolo, A., additional, Le Bouquin, J.-B., additional, Christiaens, V., additional, Milli, J., additional, Bonsor, A., additional, Olofsson, J., additional, Su, K. Y. L., additional, and Augereau, J.-C., additional
Published: 2021
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39. Large granulation cells on the surface of the giant star 1 Gruis

Author: Paladini, C., Baron, F., Jorissen, A., Le Bouquin, J.-B., Freytag, B., Van Eck, S., Wittkowski, M., Hron, J., Chiavassa, A., Berger, J.-P., Siopis, C., Mayer, A., Sadowski, G., Kravchenko, K., Shetye, S., Kerschbaum, F., Kluska, J., and Ramstedt, S.
Subjects: Observations, Stars -- Observations, Convection (Fluid dynamics) -- Observations
Abstract: Author(s): C. Paladini (corresponding author) [1, 2]; F. Baron [3]; A. Jorissen [1]; J.-B. Le Bouquin [4]; B. Freytag [5]; S. Van Eck [1]; M. Wittkowski [6]; J. Hron [7]; [...]
Published: 2018
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40. The ExoGRAVITY project: using single mode interferometry to characterize exoplanets

Author: Lacour, S., Wang, J.J., Nowak, M., Pueyo, L., Eisenhauer, F., Lagrange, A.-M., Mollière, P., Abuter, R., Amorin, A., Asensio-Torres, R., Bauböck, M., Benisty, M., Berger, J.P., Beust, H., Blunt, S., Boccaletti, A., Bohn, A., Bonnefoy, M., Bonnet, H., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V., Clénet, Y., Cridland, A., Zeeuw, P.T. de, Dembet, R., Dexter, J., Drescher, A., Duvert, G., Gao, F., Garcia, P., Garcia Lopez, R., Gardner, T., Gendron, E., Genzel, R., Gillessen, S., Girard, J.H., Haubois, X., Heißel, G., Henning, T., Hinkley, S., Hippler, S., Horrobin, M., Houllé, M., Hubert, Z., Jiménez-Rosales, A., Jocou, L., Kammerer, J., Keppler, M., Kervella, P., Kreidberg, L., Lapeyrère, V., Le Bouquin, J.-B., Léna, P., Lutz, D., Maire, A.-L., Mérand, A., Monnier, J.D., Mouillet, D., Muller, A., Nasedkin, E., Ott, T., Otten, G.P.P.L., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rameau, J., Rodet, L., Rodriguez-Coira, G., Rousset, G., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Stolker, T., Dishoeck, E.F. van, Vigan, A., Vincent, F., von Fellenberg, S.D., Ward-Duong, K., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Sallum, S., Tuthill, P.G., Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Tuthill, Peter G., Mérand, Antoine, Sallum, Stephanie, Sallum, S., and Tuthill, P.G.
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Orbital elements, Metallicity, Conjunction (astronomy), FOS: Physical sciences, Astronomy, Surface gravity, 01 natural sciences, Exoplanet, 010309 optics, Stars, 13. Climate action, Planet, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Adaptive optics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
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, H$_2$O, CH$_4$, CO$_2$). 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., SPIE 2020, invited talk
Published: 2020
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41. Carina High-contrast Imaging Project for massive Stars (CHIPS)

Author: Rainot, A., Reggiani, M., Sana, H., Bodensteiner, J., Gomez-Gonzalez, C. A., Absil, O., Christiaens, V., Delorme, P., Almeida, L. A., Caballero-Nieves, S., De Ridder, J., Kratter, K., Lacour, S., Le Bouquin, J.-B., Pueyo, L., Zinnecker, H., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: stars: massive, [PHYS]Physics [physics], stars: individual: QZ Car, Astrophysics - Solar and Stellar Astrophysics, binaries : close, Astrophysics::Solar and Stellar Astrophysics, techniques: high angular resolution, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, stars: early-type, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], binaries: visual, Astrophysics::Galaxy Astrophysics
Abstract: International audience; Context. Massive stars like company. However, low-mass companions have remained extremely difficult to detect at angular separations ( ρ ) smaller than 1″ (approx. 1000–3000 au, considering the typical distance to nearby massive stars) given the large brightness contrast between the companion and the central star. Constraints on the low-mass end of the companions mass-function for massive stars are needed, however, for helping, for example, to distinguish among the various scenarios that describe the formation of massive stars. Aims. With the aim of obtaining a statistically significant constraint on the presence of low-mass companions beyond the typical detection limit of current surveys (Δmag ≲ 5 at ρ ≲ 1″), we initiated a survey of O and Wolf-Rayet stars in the Carina region using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) coronagraphic instrument on the Very Large Telescope (VLT). In this, the first paper of the series, we aim to introduce the survey, to present the methodology and to demonstrate the capability of SPHERE for massive stars using the multiple system QZ Car. Methods. We obtained VLT-SPHERE snapshot observations in the IRDIFS_EXT mode, which combines the IFS and IRDIS sub-systems and simultaneously provides us four-dimensional (4D) data cubes in two different fields-of-view: 1.73″ × 1.73″ for IFS (39 spectral channels across the Y J H bands) and 12″ × 12″ for IRDIS (two spectral channels across the K band). Angular- and spectral-differential imaging techniques as well as PSF-fitting were applied to detect and measure the relative flux of the companions in each spectral channel. The latter were then flux-calibrated using theoretical SED models of the central object and compared to a grid of ATLAS9 atmosphere model and (pre-)main-sequence evolutionary tracks, providing a first estimate of the physical properties of the detected companions. Results. Detection limits of 9 mag at ρ > 200 mas for IFS, and as faint as 13 mag at ρ > 1.″8 for IRDIS (corresponding to sub-solar masses for potential companions), can be reached in snapshot observations of only a few minutes integration times, allowing us to detect 19 sources around the QZ Car system. All but two are reported here for the first time. With near-IR magnitude contrasts in the range of 4 to 7.5 mag, the three brightest sources (Ab, Ad, and E) are most likely to be physically bound. They have masses in the range of 2 to 12 M ⊙ and are potentially co-eval with QZ Car central system. The remaining sources have flux contrast of 1.5 × 10 5 to 9.5 × 10 6 (Δ K ≈ 11 to 13 mag). Their presence can be explained by the local source density and they are, thus, likely to be chance alignments. If they were members of the Carina nebula, they would be sub-solar-mass pre-main sequence stars. Conclusions. Based on this proof of concept, we show that the VLT/SPHERE allows us to reach the sub-solar mass regime of the companion mass function. It paves the way for this type of observation with a large sample of massive stars to provide novel constraints on the multiplicity of massive stars in a region of the parameter space that has remained inaccessible so far.
Published: 2020
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42. Constraining particle acceleration in Sgr A(*) with simultaneous GRAVITY, Spitzer, NuSTAR, and Chandra observations

Author: Abuter, R., Amorim, A., Bauboeck, M., Baganoff, F., Berger, J. P., Boyce, H., Bonnet, H., Brandner, W., Clenet, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Dallilar, Y., Drescher, A., Eckart, A., Eisenhauer, F., Fazio, G. G., Schreiber, N. M. Foerster, Foster, K., Gammie, C., Garcia, P., Gao, F., Gendron, E., Genzel, R., Ghisellini, G., Gillessen, S., Gurwell, M. A., Habibi, M., Haggard, D., Hailey, C., Harrison, F. A., Haubois, X., Heissel, G., Henning, T., Hippler, S., Hora, J. L., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lowrance, P. J., Lutz, D., Markoff, S., Mori, K., Morris, M. R., Neilsen, J., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Ponti, G., Pfuhl, O., Rabien, S., Rodriguez-Coira, G., Shangguan, J., Shimizu, T., Scheithauer, S., Smith, H. A., Stadler, J., Stern, D. K., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I, Widmann, F., Wieprecht, E., Wiezorrek, E., Willner, S. P., Witzel, G., Woillez, J., Yazici, S., Young, A., Zhang, S., Zins, G., Abuter, R., Amorim, A., Bauboeck, M., Baganoff, F., Berger, J. P., Boyce, H., Bonnet, H., Brandner, W., Clenet, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Dallilar, Y., Drescher, A., Eckart, A., Eisenhauer, F., Fazio, G. G., Schreiber, N. M. Foerster, Foster, K., Gammie, C., Garcia, P., Gao, F., Gendron, E., Genzel, R., Ghisellini, G., Gillessen, S., Gurwell, M. A., Habibi, M., Haggard, D., Hailey, C., Harrison, F. A., Haubois, X., Heissel, G., Henning, T., Hippler, S., Hora, J. L., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lowrance, P. J., Lutz, D., Markoff, S., Mori, K., Morris, M. R., Neilsen, J., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Ponti, G., Pfuhl, O., Rabien, S., Rodriguez-Coira, G., Shangguan, J., Shimizu, T., Scheithauer, S., Smith, H. A., Stadler, J., Stern, D. K., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I, Widmann, F., Wieprecht, E., Wiezorrek, E., Willner, S. P., Witzel, G., Woillez, J., Yazici, S., Young, A., Zhang, S., and Zins, G.
Abstract: We report the time-resolved spectral analysis of a bright near-infrared and moderate X-ray flare of Sgr A(*). We obtained light curves in the M, K, and H bands in the mid- and near-infrared and in the 2 - 8 keV and 2 - 70 keV bands in the X-ray. The observed spectral slope in the near-infrared band is nu L-nu proportional to proportional to nu(0.5 +/- 0.2); the spectral slope observed in the X-ray band is nu L-nu proportional to nu(-0.7 +/- 0.5). Using a fast numerical implementation of a synchrotron sphere with a constant radius, magnetic field, and electron density (i.e., a one-zone model), we tested various synchrotron and synchrotron self-Compton scenarios. The observed near-infrared brightness and X-ray faintness, together with the observed spectral slopes, pose challenges for all models explored. We rule out a scenario in which the near-infrared emission is synchrotron emission and the X-ray emission is synchrotron self-Compton. Two realizations of the one-zone model can explain the observed flare and its temporal correlation: one-zone model in which the near-infrared and X-ray luminosity are produced by synchrotron self-Compton and a model in which the luminosity stems from a cooled synchrotron spectrum. Both models can describe the mean spectral energy distribution (SED) and temporal evolution similarly well. In order to describe the mean SED, both models require specific values of the maximum Lorentz factor gamma(max), which differ by roughly two orders of magnitude. The synchrotron self-Compton model suggests that electrons are accelerated to gamma(max)similar to 500, while cooled synchrotron model requires acceleration up to gamma(max)similar to 5 x 10(4). The synchrotron self-Compton scenario requires electron densities of 10(10) cm(-3) that are much larger than typical ambient densities in the accretion flow. Furthermore, it requires a variation of the particle density that is inconsistent with the average mass-flow rate inferred from polarization measu
Published: 2021

43. The mass of beta Pictoris c from beta Pictoris b orbital motion

Author: Lacour, S., Wang, J. J., Rodet, L., Nowak, M., Shangguan, J., Beust, H., Lagrange, A-M, Abuter, R., Amorim, A., Asensio-Torres, R., Benisty, M., Berger, J-P, Blunt, S., Boccaletti, A., Bohn, A., Bolzer, M-L, Bonnefoy, M., Bonnet, H., Bourdarot, G., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V, Clenet, Y., du Foresto, V. Coude, Cridland, A., Dembet, R., Dexter, J., de Zeeuw, T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Gao, F., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Girard, J. H., Haubois, X., Heissel, G., Henning, Th, Hinkley, S., Hippler, S., Horrobin, M., Houlle, M., Hubert, Z., Jocou, L., Kammerer, J., Keppler, M., Kervella, P., Kreidberg, L., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Maire, A-L, Merand, A., Molliere, P., Monnier, J. D., Mouillet, D., Nasedkin, E., Ott, T., Otten, G. P. P. L., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rickman, E., Pueyo, L., Rameau, J., Rousset, G., Rustamkulov, Z., Samland, M., Shimizu, T., Sing, D., Stadler, J., Stolker, T., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., van Dishoeck, E. F., Vigan, A., Vincent, F., von Fellenberg, S. D., Ward-Duong, K., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., Lacour, S., Wang, J. J., Rodet, L., Nowak, M., Shangguan, J., Beust, H., Lagrange, A-M, Abuter, R., Amorim, A., Asensio-Torres, R., Benisty, M., Berger, J-P, Blunt, S., Boccaletti, A., Bohn, A., Bolzer, M-L, Bonnefoy, M., Bonnet, H., Bourdarot, G., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V, Clenet, Y., du Foresto, V. Coude, Cridland, A., Dembet, R., Dexter, J., de Zeeuw, T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Gao, F., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Girard, J. H., Haubois, X., Heissel, G., Henning, Th, Hinkley, S., Hippler, S., Horrobin, M., Houlle, M., Hubert, Z., Jocou, L., Kammerer, J., Keppler, M., Kervella, P., Kreidberg, L., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Maire, A-L, Merand, A., Molliere, P., Monnier, J. D., Mouillet, D., Nasedkin, E., Ott, T., Otten, G. P. P. L., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rickman, E., Pueyo, L., Rameau, J., Rousset, G., Rustamkulov, Z., Samland, M., Shimizu, T., Sing, D., Stadler, J., Stolker, T., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., van Dishoeck, E. F., Vigan, A., Vincent, F., von Fellenberg, S. D., Ward-Duong, K., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., and Young, A.
Abstract: Aims. We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from the astrometry of another exoplanet. Methods. We combined previous astrometry of beta Pictoris b with a new set of observations from the GRAVITY interferometer. The orbital motion of beta Pictoris b is fit using Markov chain Monte Carlo simulations in Jacobi coordinates. The inner planet, beta Pictoris c, was also reobserved at a separation of 96 mas, confirming the previous orbital estimations. Results. From the astrometry of planet b only, we can (i) detect the presence of beta Pictoris c and (ii) constrain its mass to 10.04(-3.10)(+4.53) M-Jup . If one adds the astrometry of beta Pictoris c, the mass is narrowed down to 9.15(-1.06)(+1.08) M-Jup. The inclusion of radial velocity measurements does not affect the orbital parameters significantly, but it does slightly decrease the mass estimate to 8.89(-0.75)(+0.75) M-Jup.With a semimajor axis of 2.68 +/- 0.02 au, a period of 1221 +/- 15 days, and an eccentricity of 0.32 +/- 0.02, the orbital parameters of beta Pictoris c are now constrained as precisely as those of beta Pictoris b. The orbital configuration is compatible with a high-order mean-motion resonance (7:1). The impact of the resonance on the planets' dynamics would then be negligible with respect to the secular perturbations, which might have played an important role in the eccentricity excitation of the outer planet.
Published: 2021

44. The GRAVITY young stellar object survey VIII. Gas and dust faint inner rings in the hybrid disk of HD141569

Author: Ganci, V., Labadie, L., Klarmann, L., de Valon, A., Perraut, K., Benisty, M., Brandner, W., Garatti, A. Caratti O., Dougados, C., Eupen, F., Garcia Lopez, R., Grellmann, R., Sanchez-Bermudez, J., Wojtczak, A., Garcia, P., Amorim, A., Baubock, M., Berger, J. -P., Caselli, P., Clenet, Y., Coude du Foresto, V., de Zeeuw, P. T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Hubert, Z., Jimenez-Rosales, A., Jocou, L., Kervella, P., Lacour, S., Lapeyrere, V., Le Bouquin, J-B., Lena, P., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Rousset, G., Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S. D., Widmann, F., Woillez, J., Ganci, V., Labadie, L., Klarmann, L., de Valon, A., Perraut, K., Benisty, M., Brandner, W., Garatti, A. Caratti O., Dougados, C., Eupen, F., Garcia Lopez, R., Grellmann, R., Sanchez-Bermudez, J., Wojtczak, A., Garcia, P., Amorim, A., Baubock, M., Berger, J. -P., Caselli, P., Clenet, Y., Coude du Foresto, V., de Zeeuw, P. T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Hubert, Z., Jimenez-Rosales, A., Jocou, L., Kervella, P., Lacour, S., Lapeyrere, V., Le Bouquin, J-B., Lena, P., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Rousset, G., Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S. D., Widmann, F., and Woillez, J.
Abstract: Context. The formation and evolution of planetary systems impact the evolution of the primordial accretion disk in its dust and gas content. HD 141569 is a peculiar object in this context as it is the only known pre-main sequence star characterized by a hybrid disk. Observations with 8 m class telescopes probed the outer-disk structure showing a complex system of multiple rings and outer spirals. Furthermore, interferometric observations attempted to characterize its inner 5 au region, but derived limited constraints. Aims. The goal of this work was to explore with new high-resolution interferometric observations the geometry, properties, and dynamics of the dust and gas in the internal regions of HD 141569. Methods. We observed HD 141569 on milliarcsecond scales with GRAVITY/VLTI in the near-infrared (IR) at low (R similar to 20) and high (R similar to 4000) spectral resolution. We interpreted the interferometric visibilities and spectral energy distribution with geometrical models and through radiative transfer techniques using the code MCMax to constrain the dust emission. We analyzed the high spectral resolution quantities (visibilities and differential phases) to investigate the properties of the Brackett-gamma (Br gamma) line emitting region. Results. Thanks to the combination of three different epochs, GRAVITY resolves the inner dusty disk in the K band with squared visibilities down to V-2 similar to 0.8. A differential phase signal is also detected in the region of the Br gamma line along most of the six baselines. Data modeling shows that an IR excess of about 6% is spatially resolved and that the origin of this emission is confined in a ring of material located at a radius of similar to 1 au from the star with a width less than or similar to 0.3 au. The MCMax modeling suggests that this emission could originate from a small amount (1.4 x 10(-8) M-circle plus) of quantum-heated particles, while large silicate grain models cannot reproduce at the same time
Published: 2021

45. Improved GRAVITY astrometric accuracy from modeling optical aberrations

Author: Abuter, R., Amorim, A., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Clenet, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Dallilar, Y., Drescher, A., Eckart, A., Eisenhauer, F., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Rodriguez-Coira, G., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I, Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., Zins, G., Abuter, R., Amorim, A., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Clenet, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Dallilar, Y., Drescher, A., Eckart, A., Eisenhauer, F., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Rodriguez-Coira, G., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I, Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Young, A., and Zins, G.
Abstract: The GRAVITY instrument on the ESO VLTI pioneers the field of high-precision near-infrared interferometry by providing astrometry at the 10-100 mu as level. Measurements at this high precision crucially depend on the control of systematic effects. We investigate how aberrations introduced by small optical imperfections along the path from the telescope to the detector affect the astrometry. We develop an analytical model that describes the effect of these aberrations on the measurement of complex visibilities. Our formalism accounts for pupil-plane and focal-plane aberrations, as well as for the interplay between static and turbulent aberrations, and it successfully reproduces calibration measurements of a binary star. The Galactic Center observations with GRAVITY in 2017 and 2018, when both Sgr A* and the star S2 were targeted in a single fiber pointing, are affected by these aberrations at a level lower than 0.5 mas. Removal of these effects brings the measurement in harmony with the dual-beam observations of 2019 and 2020, which are not affected by these aberrations. This also resolves the small systematic discrepancies between the derived distance R-0 to the Galactic Center that were reported previously.
Published: 2021

46. The GRAVITY young stellar object survey: IV. The CO overtone emission in 51 Oph at sub-au scales

Author: Koutoulaki, M., Lopez, R. Garcia, Natta, A., Fedriani, R., Garatti, A. Caratti O., Ray, T. P., Coffey, D., Brandner, W., Dougados, C., Garcia, P. J., V, Klarmann, L., Labadie, L., Perraut, K., Sanchez-Bermudez, J., Lin, C-C, Amorim, A., Bauboeck, M., Benisty, M., Berger, J. P., Buron, A., Caselli, P., Clenet, Y., du Foresto, V. Coude, de Zeeuw, P. T., Duvert, G., de Wit, W., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Habibi, M., Haubois, X., Haussmann, F., Henning, T., Hippler, S., Hubert, Z., Horrobin, M., Rosales, A. Jimenez, Jocou, L., Kervella, P., Kolb, J., Lacour, S., Le Bouquin, J-B, Lena, P., Linz, H., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Ramirez-Tannus, M. C., Rau, C., Rousset, G., Scheithauer, S., Shangguan, J., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Yazici, S., Zins, G., Koutoulaki, M., Lopez, R. Garcia, Natta, A., Fedriani, R., Garatti, A. Caratti O., Ray, T. P., Coffey, D., Brandner, W., Dougados, C., Garcia, P. J., V, Klarmann, L., Labadie, L., Perraut, K., Sanchez-Bermudez, J., Lin, C-C, Amorim, A., Bauboeck, M., Benisty, M., Berger, J. P., Buron, A., Caselli, P., Clenet, Y., du Foresto, V. Coude, de Zeeuw, P. T., Duvert, G., de Wit, W., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Habibi, M., Haubois, X., Haussmann, F., Henning, T., Hippler, S., Hubert, Z., Horrobin, M., Rosales, A. Jimenez, Jocou, L., Kervella, P., Kolb, J., Lacour, S., Le Bouquin, J-B, Lena, P., Linz, H., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Ramirez-Tannus, M. C., Rau, C., Rousset, G., Scheithauer, S., Shangguan, J., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Yazici, S., and Zins, G.
Abstract: Context. 51 Oph is a Herbig Ae/Be star that exhibits strong near-infrared CO ro-vibrational emission at 2.3 mu m, most likely originating in the innermost regions of a circumstellar disc.Aims. We aim to obtain the physical and geometrical properties of the system by spatially resolving the circumstellar environment of the inner gaseous disc.Methods. We used the second-generation Very Large Telescope Interferometer instrument GRAVITY to spatially resolve the continuum and the CO overtone emission. We obtained data over 12 baselines with the auxiliary telescopes and derive visibilities, and the differential and closure phases as a function of wavelength. We used a simple local thermal equilibrium ring model of the CO emission to reproduce the spectrum and CO line displacements.Results. Our interferometric data show that the star is marginally resolved at our spatial resolution, with a radius of similar to 10.58 2.65R(circle dot). The K-band continuum emission from the disc is inclined by 63 degrees +/- 1 degrees, with a position angle of 116 degrees +/- 1 degrees, and 4 +/- 0.8 mas (0.5 +/- 0.1 au) across. The visibilities increase within the CO line emission, indicating that the CO is emitted within the dust-sublimation radius. By modelling the CO bandhead spectrum, we derive that the CO is emitted from a hot (T = 1900-2800 K) and dense (N-CO = (0.9-9) x 10(21) cm(-2)) gas. The analysis of the CO line displacement with respect to the continuum allows us to infer that the CO is emitted from a region 0.10 +/- 0.02 au across, well within the dust-sublimation radius. The inclination and position angle of the CO line emitting region is consistent with that of the dusty disc.Conclusions. Our spatially resolved interferometric observations confirm the CO ro-vibrational emission within the dust-free region of the inner disc. Conventional disc models exclude the presence of CO in the dust-depleted regions of Herbig AeBe stars. Ad hoc models of the innermost disc regions, that
Published: 2021

47. Detection of faint stars near Sagittarius A* with GRAVITY

Author: Abuter, R., Amorim, A., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Clenet, Y., Dallilar, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Drescher, A., Eisenhauer, F., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V., Le Bouquin, J. -B., Lena, P., Lutz, D., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Rodriguez-Coira, G., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Zins, G., Abuter, R., Amorim, A., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Clenet, Y., Dallilar, Y., Davies, R., de Zeeuw, P. T., Dexter, J., Drescher, A., Eisenhauer, F., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V., Le Bouquin, J. -B., Lena, P., Lutz, D., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rabien, S., Rodriguez-Coira, G., Shangguan, J., Shimizu, T., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., and Zins, G.
Abstract: The spin of the supermassive black hole that resides at the Galactic Center can, in principle, be measured by accurate measurements of the orbits of stars that are much closer to Sgr A* than S2, the orbit of which recently provided the measurement of the gravitational redshift and the Schwarzschild precession. The GRAVITY near-infrared interferometric instrument combining the four 8m telescopes of the VLT provides a spatial resolution of 2-4 mas, breaking the confusion barrier for adaptive-optics-assisted imaging with a single 8-10m telescope. We used GRAVITY to observe Sgr A* over a period of six months in 2019 and employed interferometric reconstruction methods developed in radio astronomy to search for faint objects near Sgr A*. This revealed a slowly moving star of magnitude 18.9 in the K-band within 30 mas of Sgr A*. The position and proper motion of the star are consistent with the previously known star S62, which is at a substantially greater physical distance, but in projection passes close to Sgr A*. Observations in August and September 2019 detected S29 easily, with K-magnitude of 16.6, at approximately 130 mas from Sgr A*. The planned upgrades of GRAVITY, and further improvements in the calibration, offer greater chances of finding stars fainter than K-magnitude of 19.
Published: 2021

48. The GRAVITY young stellar object survey VII. The inner dusty disks of T Tauri stars

Author: Perraut, K., Labadie, L., Bouvier, J., Menard, F., Klarmann, L., Dougados, C., Benisty, M., Berger, J-P, Bouarour, Y-, I, Brandner, W., Garatti, A. Caratti o, Caselli, P., de Zeeuw, P. T., Garcia-Lopez, R., Henning, T., Sanchez-Bermudez, J., Sousa, A., van Dishoeck, E., Alecian, E., Amorim, A., Clenet, Y., Davies, R., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Foerster-Schreiber, N. M., Garcia, P., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Heissel, G., Hippler, S., Horrobin, M., Hubert, Z., Jocou, L., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Ott, T., Paumard, T., Perrin, G., Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L., Vincent, F., von Fellenberg, S., Widmann, F., Perraut, K., Labadie, L., Bouvier, J., Menard, F., Klarmann, L., Dougados, C., Benisty, M., Berger, J-P, Bouarour, Y-, I, Brandner, W., Garatti, A. Caratti o, Caselli, P., de Zeeuw, P. T., Garcia-Lopez, R., Henning, T., Sanchez-Bermudez, J., Sousa, A., van Dishoeck, E., Alecian, E., Amorim, A., Clenet, Y., Davies, R., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Foerster-Schreiber, N. M., Garcia, P., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Heissel, G., Hippler, S., Horrobin, M., Hubert, Z., Jocou, L., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Ott, T., Paumard, T., Perrin, G., Scheithauer, S., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L., Vincent, F., von Fellenberg, S., and Widmann, F.
Abstract: Context. T Tauri stars are surrounded by dust and gas disks. As material reservoirs from which matter is accreted onto the central star and planets are built, these protoplanetary disks play a central role in star and planet formation. Aims. We aim at spatially resolving at sub-astronomical unit (sub-au) scales the innermost regions of the protoplanetary disks around a sample of T Tauri stars to better understand their morphology and composition. Methods. Thanks to the sensitivity and the better spatial frequency coverage of the GRAVITY instrument of the Very Large Telescope Interferometer, we extended our homogeneous data set of 27 Herbig stars and collected near-infrared K-band interferometric observations of 17 T Tauri stars, spanning effective temperatures and luminosities in the ranges of similar to 4000-6000 K and similar to 0.4-10 L-circle dot, respectively. We focus on the continuum emission and develop semi-physical geometrical models to fit the interferometric data and search for trends between the properties of the disk and the central star. Results. As for those of their more massive counterparts, the Herbig Ae/Be stars, the best-fit models of the inner rim of the T Tauri disks correspond to wide rings. The GRAVITY measurements extend the radius-luminosity relation toward the smallest luminosities (0.4-10 L-circle dot). As observed previously, in this range of luminosities, the R proportional to L-1/2 trend line is no longer valid, and the K-band sizes measured with GRAVITY appear to be larger than the predicted sizes derived from sublimation radius computation. We do not see a clear correlation between the K-band half-flux radius and the mass accretion rate onto the central star. Besides, having magnetic truncation radii in agreement with the K-band GRAVITY sizes would require magnetic fields as strong as a few kG, which should have been detected, suggesting that accretion is not the main process governing the location of the half-flux radius of the inn
Published: 2021

49. GRAVITY K-band spectroscopy of HD 206893 B Brown dwarf or exoplanet

Author: Kammerer, J., Lacour, S., Stolker, T., Molliere, P., Sing, D. K., Nasedkin, E., Kervella, P., Wang, J. J., Ward-Duong, K., Nowak, M., Abuter, R., Amorim, A., Asensio-Torres, R., Baubock, M., Benisty, M., Berger, J-P, Beust, H., Blunt, S., Boccaletti, A., Bohn, A., Bolzer, M-L, Bonnefoy, M., Bonnet, H., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V, Clenet, Y., du Foresto, V. Coude, Cridland, A., Dembet, R., Dexter, J., de Zeeuw, P. T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Gao, F., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Girard, J., Haubois, X., Heissel, G., Henning, T., Hinkley, S., Hippler, S., Horrobin, M., Houlle, M., Hubert, Z., Jocou, L., Keppler, M., Kreidberg, L., Lagrange, A-M, Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Maire, A-L, Merand, A., Monnier, J. D., Mouillet, D., Muller, A., Ott, T., Otten, G. P. P. L., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Pueyo, L., Rameau, J., Rodet, L., Rousset, G., Rustamkulov, Z., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., van Dishoeck, E. F., Vigan, A., Vincent, F., von Fellenberg, S. D., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S., Kammerer, J., Lacour, S., Stolker, T., Molliere, P., Sing, D. K., Nasedkin, E., Kervella, P., Wang, J. J., Ward-Duong, K., Nowak, M., Abuter, R., Amorim, A., Asensio-Torres, R., Baubock, M., Benisty, M., Berger, J-P, Beust, H., Blunt, S., Boccaletti, A., Bohn, A., Bolzer, M-L, Bonnefoy, M., Bonnet, H., Brandner, W., Cantalloube, F., Caselli, P., Charnay, B., Chauvin, G., Choquet, E., Christiaens, V, Clenet, Y., du Foresto, V. Coude, Cridland, A., Dembet, R., Dexter, J., de Zeeuw, P. T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Gao, F., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Girard, J., Haubois, X., Heissel, G., Henning, T., Hinkley, S., Hippler, S., Horrobin, M., Houlle, M., Hubert, Z., Jocou, L., Keppler, M., Kreidberg, L., Lagrange, A-M, Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lutz, D., Maire, A-L, Merand, A., Monnier, J. D., Mouillet, D., Muller, A., Ott, T., Otten, G. P. P. L., Paladini, C., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Pueyo, L., Rameau, J., Rodet, L., Rousset, G., Rustamkulov, Z., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., van Dishoeck, E. F., Vigan, A., Vincent, F., von Fellenberg, S. D., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., and Yazici, S.
Abstract: Context. Near-infrared interferometry has become a powerful tool for studying the orbital and atmospheric parameters of substellar companions. Aims. We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion. Methods. We fit atmospheric models for giant planets and brown dwarfs and perform spectral retrievals with petitRADTRANS and ATMO on the observed GRAVITY, SPHERE, and GPI spectra of HD 206893 B. To recover its unusual spectral features, first and foremost its extremely red near-infrared color, we include additional extinction by high-altitude dust clouds made of enstatite grains in the atmospheric model fits. However, forsterite, corundum, and iron grains predict similar extinction curves for the grain sizes considered here. We also infer the orbital parameters of HD 206893 B by combining the similar to 100 mu as precision astrometry from GRAVITY with data from the literature and constrain the mass and position of HD 206893 C based on the Gaia proper motion anomaly of the system. Results. The extremely red color and the very shallow 1.4 mu m water absorption feature of HD 206893 B can be fit well with the adapted atmospheric models and spectral retrievals. By comparison with AMES-Cond evolutionary tracks, we find that only some atmosphericmodels predict physically plausible objects. Altogether, our analysis suggests an age of similar to 3-300 Myr and a mass of similar to 5-30 M-Jup for HD 206893 B, which is consistent with previous estimates but extends the parameter space to younger and lower-mass objects. The GRAVITY astrometry points to an eccentric orbit (e = 0.29(-0.11)(+0.06)) with a mutual inclination of <34.4 deg with respect to the debris disk of the system. Conclusions. While HD 206893 B could in principle be a planetary-mass companion, this possibility hinges on the unknown influence of the inner companion on the mass estimate o
Published: 2021

50. The GRAVITY young stellar object survey VI. Mapping the variable inner disk of HD 163296 at sub-au scales

Author: Sanchez-Bermudez, J., Garatti, A. Caratti O., Lopez, R. Garcia, Perraut, K., Labadie, L., Benisty, M., Brandner, W., Dougados, C., Garcia, P. J., V, Henning, Th, Klarmann, L., Amorim, A., Bauboeck, M., Berger, J. P., Le Bouquin, J. B., Caselli, P., Clenet, Y., du Foresto, V. Coude, de Zeeuw, P. T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Heissel, G., Horrobin, M., Hubert, Z., Jimenez-Rosales, A., Jocou, L., Kervella, P., Lacour, S., Lapeyrere, V, Lena, P., Ott, T., Paumard, T., Perrin, G., Pineda, J. E., Rodriguez-Coira, G., Rousset, G., Segura-Cox, D. M., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S. D., Widmann, F., Woillez, J., Sanchez-Bermudez, J., Garatti, A. Caratti O., Lopez, R. Garcia, Perraut, K., Labadie, L., Benisty, M., Brandner, W., Dougados, C., Garcia, P. J., V, Henning, Th, Klarmann, L., Amorim, A., Bauboeck, M., Berger, J. P., Le Bouquin, J. B., Caselli, P., Clenet, Y., du Foresto, V. Coude, de Zeeuw, P. T., Drescher, A., Duvert, G., Eckart, A., Eisenhauer, F., Filho, M., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Grellmann, R., Heissel, G., Horrobin, M., Hubert, Z., Jimenez-Rosales, A., Jocou, L., Kervella, P., Lacour, S., Lapeyrere, V, Lena, P., Ott, T., Paumard, T., Perrin, G., Pineda, J. E., Rodriguez-Coira, G., Rousset, G., Segura-Cox, D. M., Shangguan, J., Shimizu, T., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., van Dishoeck, E., Vincent, F., von Fellenberg, S. D., Widmann, F., and Woillez, J.
Abstract: Context. Protoplanetary disks drive some of the formation process (e.g., accretion, gas dissipation, formation of structures) of stars and planets. Understanding such physical processes is one of the most significant astrophysical questions. HD 163296 is an interesting young stellar object for which infrared and sub-millimeter observations have shown a prominent circumstellar disk with gaps plausibly created by forming planets. Aims. This study aims to characterize the morphology of the inner disk in HD 163296 with multi-epoch, near-infrared interferometric observations performed with GRAVITY at the Very Large Telescope Interferometer. Our goal is to depict the K-band (lambda(0) similar to 2.2 mu m) structure of the inner rim with milliarcsecond (sub-au) angular resolution. Our data is complemented with archival Precision Integrated-Optics Near-infrared Imaging ExpeRiment (H-band; lambda(0) similar to 1.65 mu m) data of the source. Methods. We performed a gradient descent parametric model fitting to recover the sub-au morphology of our source. Results. Our analysis shows the existence of an asymmetry in the disk surrounding the central star of HD 163296. We confirm variability of the disk structure in the inner similar to 2 mas (0.2 au). While variability of the inner disk structure in this source has been suggested by previous interferometric studies, this is the first time that it is confirmed in the H- and K-bands by using a complete analysis of the closure phases and squared visibilities over several epochs. Because of the separation from the star, position changes, and the persistence of this asymmetric structure on timescales of several years, we argue that it is probably a dusty feature (e.g., a vortex or dust clouds) made by a mixing of silicate and carbon dust and/or refractory grains, inhomogeneously distributed above the mid-plane of the disk.
Published: 2021

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