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11 results on '"Riggs, A. J. E."'

1. Hybrid propagation physics for the design and modeling of astronomical observatories: a coronagraphic example

Author

Ashcraft, Jaren N., Douglas, Ewan S., Kim, Daewook, and Riggs, A. J. E.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

For diffraction-limited optical systems an accurate physical optics model is necessary to properly evaluate instrument performance. Astronomical observatories outfitted with coronagraphs for direct exoplanet imaging require physical optics models to simulate the effects of misalignment and diffraction. Accurate knowledge of the observatory's PSF is integral for the design of high-contrast imaging instruments and simulation of astrophysical observations. The state of the art is to model the misalignment, ray aberration, and diffraction across multiple software packages, which complicates the design process. Gaussian Beamlet Decomposition (GBD) is a ray-based method of diffraction calculation that has been widely implemented in commercial optical design software. By performing the coherent calculation with data from the ray model of the observatory, the ray aberration errors can be fed directly into the physical optics model of the coronagraph, enabling a more integrated model of the observatory. We develop a formal algorithm for the transfer-matrix method of GBD, and evaluate it against analytical results and a traditional physical optics model to assess the suitability of GBD for high-contrast imaging simulations. Our GBD simulations of the observatory PSF, when compared to the analytical Airy function, have a sum-normalized RMS difference of ~10^-6. These fields are then propagated through a Fraunhofer model of a exoplanet imaging coronagraph where the mean residual numerical contrast is 4x10^-11, with a maximum near the inner working angle at 5x10^-9. These results show considerable promise for the future development of GBD as a viable propagation technique in high-contrast imaging. We developed this algorithm in an open-source software package and outlined a path for its continued development to increase the fidelity and flexibility of diffraction simulations using GBD., Comment: 58 pages, 15 figures, preprint version for article in press. Accepted to SPIE's Journal of Astronomical Telescopes, Instruments, and Systems on October 23 2023

Published
2023

2. Poke: An open-source ray-based physical optics platform

Author

Ashcraft, Jaren N., Douglas, Ewan S., Kim, Daewook, Riggs, A. J. E., Anche, Ramya, Brendel, Trent, Derby, Kevin, Dube, Brandon D., Jarecki, Quinn, Jenkins, Emory, and Milani, Kian

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Integrated optical models allow for accurate prediction of the as-built performance of an optical instrument. Optical models are typically composed of a separate ray trace and diffraction model to capture both the geometrical and physical regimes of light. These models are typically separated across both open-source and commercial software that don't interface with each other directly. To bridge the gap between ray trace models and diffraction models, we have built an open-source optical analysis platform in Python called Poke that uses commercial ray tracing APIs and open-source physical optics engines to simultaneously model scalar wavefront error, diffraction, and polarization. Poke operates by storing ray data from a commercial ray tracing engine into a Python object, from which physical optics calculations can be made. We present an introduction to using Poke, and highlight the capabilities of two new propagation physics modules that add to the utility of existing scalar diffraction models. Gaussian Beamlet Decomposition is a ray-based approach to diffraction modeling that allows us to integrate physical optics models with ray trace models to directly capture the influence of ray aberrations in diffraction simulations. Polarization Ray Tracing is a ray-based method of vector field propagation that can diagnose the polarization aberrations in optical systems. Poke has been recently used to study the next generation of astronomical observatories, including the ground-based Extremely Large Telescopes and a 6 meter space telescope early concept for NASA's Habitable Worlds Observatory., Comment: 11 Pages, 9 Figures, Published in Proceedings of SPIE Optical Modeling and Performance Predictions XIII Paper 12664-5

Published
2023

3. The Potential of Exozodiacal Disks Observations with the WFIRST Coronagraph Instrument

Author

Mennesson, B., Bailey, V., Kasdin, J., Trauger, J., Absil, O., Akeson, R., Armus, L., Baudino, J. L., Baudoz, P., Bellini, A., Bennett, D., Berriman, B., Boccaletti, A., Calchi-Novati, S., Carpenter, K., Chen, C., Danchi, W., Debes, J., Defrere, D., Ertel, S., Frerking, M., Gelino, C., Girard, J., Groff, T., Kane, S., Helou, G., Kalirai, J., Kral, Q., Krist, J., Kruk, J., Hasegawa, Y., Lagrange, A. M., Laine, S., Langlois, M., Lowrance, P., Maire, A. L., Malhotra, S., Mandell, A., Marshall, P., McElwain, M., Meshkat, T., Millan-Gabet, R., Moustakas, L., Nemati, B., Paladini, R., Postman, M., Pueyo, L., Quintana, E., Ramirez, S., Rhodes, J., Riggs, A. J. E., Rizzo, M., Rouan, D., Soummer, R., Stapelfeldt, K., Stark, C., Turnbull, M., van der Marel, R., Vigan, A., Ygouf, M., Wyatt, M., Zhao, F., and Zimmerman, N.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) will be the first high-performance stellar coronagraph using active wavefront control for deep starlight suppression in space, providing unprecedented levels of contrast, spatial resolution, and sensitivity for astronomical observations in the optical. One science case enabled by the CGI will be taking images and(R~50)spectra of faint interplanetary dust structures present in the habitable zone of nearby sunlike stars (~10 pc) and within the snow-line of more distant ones(~20pc), down to dust density levels commensurate with that of the solar system zodiacal cloud. Reaching contrast levels below~10-7 for the first time, CGI will cross an important threshold in debris disks physics, accessing disks with low enough optical depths that their structure is dominated by transport phenomena than collisions. Hence, CGI results will be crucial for determining how exozodiacal dust grains are produced and transported in low-density disks around mature stars. Additionally, CGI will be able to measure the brightness level and constrain the degree of asymmetry of exozodiacal clouds around individual nearby sunlike stars in the optical, at the ~10x solar zodiacal emission level. This information will be extremely valuable for optimizing the observational strategy of possible future exo-Earth direct imaging missions, especially those planning to operate at optical wavelengths, such as Habitable Exoplanet Observatory (HabEx) and the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR)., Comment: 6 pages, 2 figures

Published
2019

4. Simulations of a High-Contrast Single-Mode Fiber Coronagraphic Multi-Object Spectrograph for Future Space Telescopes

Author

Coker, Carl T., Shaklan, Stuart B., Riggs, A J E., and Ruane, Garreth

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Directly imaging and characterizing Earth-like exoplanets is a tremendously difficult instrumental challenge. Present coronagraphic systems have yet to achieve the required $10^{-10}$ broadband contrast in a laboratory environment, but promising progress towards this goal continues. A new approach to starlight suppression is the use of a single-mode fiber behind a coronagraph. By using deformable mirrors to create a mismatch between incoming starlight and the fiber mode, a single-mode fiber can be turned into an integral part of the starlight suppression system. In this paper, we present simulation results of a system with five single-mode fibers coupled to shaped pupil and vortex coronagraphs. We investigate the properties of the system, including its spectral bandwidth, throughput, and sensitivity to low-order aberrations. We also compare the performance of the single-mode fiber configuration with conventional imaging and multi-object modes, finding improved spectral bandwidth, raw contrast, background-limited SNR, and demonstrate a wavefront control algorithm which is robust to tip/tilt errors., Comment: 40 pages, 15 figures, 3 tables; final revised version for resubmission

Published
2019

5. Key Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument

Author

Bailey, Vanessa P., Armus, Lee, Balasubramanian, Bala, Baudoz, Pierre, Bellini, Andrea, Benford, Dominic, Berriman, Bruce, Bhattacharya, Aparna, Boccaletti, Anthony, Cady, Eric, Novati, Sebastiano Calchi, Carpenter, Kenneth, Ciardi, David, Crill, Brendan, Danchi, William, Debes, John, Demers, Richard, Dohlen, Kjetil, Effinger, Robert, Ferrari, Marc, Frerking, Margaret, Gelino, Dawn, Girard, Julien, Grady, Kevin, Groff, Tyler, Harding, Leon, Helou, George, Henning, Avenhaus, Janson, Markus, Kalirai, Jason, Kane, Stephen, Kasdin, N. Jeremy, Kenworthy, Matthew, Kern, Brian, Krist, John, Kruk, Jeffrey, Lagrange, Anne Marie, Laine, Seppo, Langlois, Maud, Coroller, Herve Le, Lindensmith, Chris, Lowrance, Patrick, Maire, Anne-Lise, Malhotra, Sangeeta, Mandell, Avi, McElwain, Michael, Prada, Camilo Mejia, Mennesson, Bertrand, Meshkat, Tiffany, Moody, Dwight, Morrissey, Patrick, Moustakas, Leonidas, N'Diaye, Mamadou, Nemati, Bijan, Noecker, Charley, Paladini, Roberta, Perrin, Marshall, Poberezhskiy, Ilya, Postman, Marc, Pueyo, Laurent, Ramirez, Solange, Ranc, Clement, Rhodes, Jason, Riggs, A. J. E., Rizzo, Maxime, Roberge, Aki, Rouan, Daniel, Schlieder, Joshua, Seo, Byoung-Joon, Shaklan, Stuart, Shi, Fang, Soummer, Remi, Spergel, David, Stapelfeldt, Karl, Stark, Christopher, Tamura, Motohide, Tang, Hong, Trauger, John, Turnbull, Margaret, van der Marel, Roeland, Vigan, Arthur, Williams, Benjamin, Wollack, Edward J., Ygouf, Marie, Zhao, Feng, Zhoud, Hanying, and Zimmerman, Neil

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post-processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures., Comment: Submitted in response to the 2018 NAS Exoplanet Science Strategy call. 5 pages, 2 figures

Published
2019

6. The low wind expansion velocity of metal-poor carbon stars in the Halo and the Sagittarius stream

Author

Lagadec, Eric, Zijlstra, Albert, Mauron, Nicolas, Fuller, Gary, Josselin, Eric, Sloan, G. C., and Riggs, A. J. E.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We report the detection, from observations using the James Clerk Maxwell Telescope, of CO J $=$ 3$\to$ 2 transition lines in six carbon stars, selected as members of the Galactic Halo and having similar infrared colors. Just one Halo star had been detected in CO before this work. Infrared observations show that these stars are red (J-K $>$3), due to the presence of large dusty circumstellar envelopes. Radiative transfer models indicates that these stars are losing mass with rather large dust mass-loss rates in the range 1--3.3 $\times$$10^{-8}$M$_{\odot}$yr$^{-1}$, similar to what can be observed in the Galactic disc. We show that two of these stars are effectively in the Halo, one is likely linked to the stream of the Sagittarius Dwarf Spheroidal galaxy (Sgr dSph), and the other three stars certainly belong to the thick disc. The wind expansion velocities of the observed stars are low compared to carbon stars in the thin disc and are lower for the stars in the Halo and the Sgr dSph stream than in the thick disc. We discuss the possibility that the low expansion velocities result from the low metallicity of the Halo carbon stars. This implies that metal-poor carbon stars lose mass at a rate similar to metal-rich carbon stars, but with lower expansion velocities, as predicted by recent theoretical models. This result implies that the current estimates of mass-loss rates from carbon stars in Local Group galaxies will have to be reconsidered., Comment: 10 pages, 7 figures, accepted for publication in MNRAS

Published
2009
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7. Key Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument

Author

Bailey, Vanessa P., Armus, Lee, Balasubramanian, Bala, Baudoz, Pierre, Bellini, Andrea, Benford, Dominic, Berriman, Bruce, Bhattacharya, Aparna, Boccaletti, Anthony, Cady, Eric, Novati, Sebastiano Calchi, Carpenter, Kenneth, Ciardi, David, Crill, Brendan, Danchi, William, Debes, John, Demers, Richard, Dohlen, Kjetil, Effinger, Robert, Ferrari, Marc, Frerking, Margaret, Gelino, Dawn, Girard, Julien, Grady, Kevin, Groff, Tyler, Harding, Leon, Helou, George, Henning, Avenhaus, Janson, Markus, Kalirai, Jason, Kane, Stephen, Kasdin, N. Jeremy, Kenworthy, Matthew, Kern, Brian, Krist, John, Kruk, Jeffrey, Lagrange, Anne Marie, Laine, Seppo, Langlois, Maud, Coroller, Herve Le, Lindensmith, Chris, Lowrance, Patrick, Maire, Anne-Lise, Malhotra, Sangeeta, Mandell, Avi, McElwain, Michael, Prada, Camilo Mejia, Mennesson, Bertrand, Meshkat, Tiffany, Moody, Dwight, Morrissey, Patrick, Moustakas, Leonidas, N'Diaye, Mamadou, Nemati, Bijan, Noecker, Charley, Paladini, Roberta, Perrin, Marshall, Poberezhskiy, Ilya, Postman, Marc, Pueyo, Laurent, Ramirez, Solange, Ranc, Clement, Rhodes, Jason, Riggs, A. J. E., Rizzo, Maxime, Roberge, Aki, Rouan, Daniel, Schlieder, Joshua, Seo, Byoung-Joon, Shaklan, Stuart, Shi, Fang, Soummer, Remi, Spergel, David, Stapelfeldt, Karl, Stark, Christopher, Tamura, Motohide, Tang, Hong, Trauger, John, Turnbull, Margaret, van der Marel, Roeland, Vigan, Arthur, Williams, Benjamin, Wollack, Edward J., Ygouf, Marie, Zhao, Feng, Zhoud, Hanying, Zimmerman, Neil, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], [SDU]Sciences of the Universe [physics], Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post-processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures., Submitted in response to the 2018 NAS Exoplanet Science Strategy call. 5 pages, 2 figures

Published
2020

8. The B-Star Exoplanet Abundance Study: a co-moving 16–25 M Jup companion to the young binary system HIP 79098

Author

Carbillet, M., Maurel, D., Origné, A., Rigal, F., Sevin, A., De Boer, J., van Holstein, R. G., Dohlen, K., Snik, F., Keller, C. U., Ginski, C., Stam, D. M., Wahhaj, Z., Kasper, M., Rabou, P., Hugot, E., Perret, D., Martinez, P., Pragt, J., Coroller, H. Le, Dominik, C., Turatto, M., Udry, S., Beuzit, J. -L., Le Coroller, H., Mennesson, B., Bailey, V., Kasdin, J., Trauger, J., Absil, O., Akeson, R., Armus, L., Baudoz, P., Bellini, A., Bennett, D., Berriman, B., Calchi-Novati, S., Carpenter, K., Chen, C., Danchi, W., Debes, J., Defrere, D., Ertel, S., Frerking, M., Gelino, C., Girard, J. H., Groff, T., Kane, S., Helou, G., Kalirai, J., Krist, J., Kruk, J., Hasegawa, Y., Laine, S., Lowrance, P., Malhotra, S., Mandell, A., Marshall, P., McElwain, M., Meshkat, T., Millan-Gabet, R., Moustakas, L., Nemati, B., Paladini, R., Postman, M., Pueyo, L., Quintana, E., Ramirez, S., Rhodes, J., Riggs, A. J. E., Rizzo, M., Soummer, R., Stapelfeldt, K., Stark, C., Turnbull, M., van der Marel, R., Ygouf, M., Wyatt, M., Zhao, F., Zimmerman, N., Loh, Alan, Messina, Sergio, Brandner, Wolfgang, Buenzli, Esther, Daemgen, Sebastien, Lagadec, Eric, Mouillet, David, Peretti, Sébastien, Janin-Potiron, Pierre, Salter, Graeme, Roux, Alain, Llored, Marc, Buey, Jean-Tristan, Pavlov, Alexei, Petit, C., Pawellek, Nicole, Moór, Attila, Milli, Julien, Kóspál, Ágnes, Olofsson, Johan, Ábrahám, Péter, Keppler, Miriam, Kral, Quentin, Pohl, Adriana, Augereau, Jean-Charles, Choquet, Elodie, Engler, Natalia, Lee, Eve J., Thebault, Philippe, Lee, Eve, Podio, L., Bacciotti, F., Antoniucci, S., Codella, C., Dougados, C., Nisini, B., Schmid, H. M., Stolker, T., Baudino, J. L., Biller, Beth, Bonavita, M., Galicher, R., Grandjean, A., Lagrange, Anne-Marie, Lannier, Justine, Maire, Anne-Lise, Perrot, Clément, Delboulbé, A., Mignant, D. Le, Fantinel, D., Moeller-Nilsson, O., Weber, Luc, Sauvage, J. -F., Le Mignant, D., Möller-Nilsson, O., Mesa, Dino, Garufi, A., D'Orazi, V., Flasseur, O., Barbieri, M., Benisty, M., Henning, Thomas, Ligi, R., Sissa, Elena, Zurlo, Alice, Boccaletti, Anthony, Cantalloube, F., Cheetham, Anthony, De Caprio, V., Feldt, Markus, Fusco, T., Gluck, L., Hagelberg, J., Lagrange, A. -M., Lazzoni, C., Madec, F., Maire, A. -L., Ménard, F., Meyer, M., Ramos, J., Rickman, E. L., Rouan, D., Schmidt, T., van der Plas, G., D’Orazi, V., De Caprio, V, Lagrange, A-M, Maire, A-L, Van der Plas, G, Janson, Markus, Asensio-Torres, Ruben, André, Damien, Bonnefoy, Mickaël, Delorme, Philippe, Reffert, Sabine, Desidera, Silvano, Langlois, M, Chauvin, G., Gratton, Raffaele, Bohn, Alexander J., Eriksson, Simon C., Marleau, Gabriel-Dominique, Mamajek, Eric E., Vigan, Arthur, Carson, Joseph C., Bohn, Alexander, Eriksson, Simon, Mamajek, Eric, Carson, Joseph, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], 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), Faculty of Aerospace Engineering [Delft], Delft University of Technology (TU Delft), Department of International Development, University of Oxford [Oxford], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY PASADENA USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), California Institute of Technology (CALTECH), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, 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), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), European Southern Observatory (ESO), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Roma (OAR), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Biochemistry and Molecular Biology, Mayo Clinic, INAF - Osservatorio Astronomico di Padova (OAPD), 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)-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), Collège de France (CdF (institution)), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Axe 4 : céramiques sous contraintes environnementales (SPCTS-AXE4), Science des Procédés Céramiques et de Traitements de Surface (SPCTS), Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Ecole Nationale Supérieure de Céramique Industrielle (ENSCI)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Stockholm University, Universität Heidelberg [Heidelberg] = Heidelberg University, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Departamento de Ingeniería Matemática [Santiago] (DIM), Universidad de Chile = University of Chile [Santiago] (UCHILE)-Centre National de la Recherche Scientifique (CNRS), Universiteit Leiden, Institut für Astronomie und Astrophysik [Tübingen] (IAAT), Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen, Department of Physics and Astronomy [Rochester], University of Rochester [USA], College of Charleston, ANR-10-LABX-0056,OSUG@2020,Innovative strategies for observing and modelling natural systems(2010), and European Project: 678194,H2020,ERC-2015-STG,FALCONER(2016)

Subjects
planets and satellites: detection, Proper motion, 010504 meteorology & atmospheric sciences, Stellar mass, Brown dwarf, FOS: Physical sciences, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Mass ratio, stars: early-type, Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Circumbinary planet, Astrophysics - Earth and Planetary Astrophysics, brown dwarfs
Abstract

Wide low-mass substellar companions are known to be very rare among low-mass stars, but appear to become increasingly common with increasing stellar mass. However, B-type stars, which are the most massive stars within ~150 pc of the Sun, have not yet been examined to the same extent as AFGKM-type stars in that regard. In order to address this issue, we launched the ongoing B-star Exoplanet Abundance Study (BEAST) to examine the frequency and properties of planets, brown dwarfs, and disks around B-type stars in the Scorpius-Centaurus (Sco-Cen) association; we also analyzed archival data of B-type stars in Sco-Cen. During this process, we identified a candidate substellar companion to the B9-type spectroscopic binary HIP 79098 AB, which we refer to as HIP 79098 (AB)b. The candidate had been previously reported in the literature, but was classified as a background contaminant on the basis of its peculiar colors. Here we demonstrate that the colors of HIP 79098 (AB)b are consistent with several recently discovered young and low-mass brown dwarfs, including other companions to stars in Sco-Cen. Furthermore, we show unambiguous common proper motion over a 15-year baseline, robustly identifying HIP 79098 (AB)b as a bona fide substellar circumbinary companion at a 345+/-6 AU projected separation to the B9-type stellar pair. With a model-dependent mass of 16-25 Mjup yielding a mass ratio of, 9 pages, 6 figures, accepted for publication in A&A

Published
2019
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9. A multi-object spectrograph using single-mode fibers with a coronagraph: progress towards laboratory results on the high-contrast testbed for segmented telescopes

Author

Shaklan, Stuart B., Coker, Carl T., Llop Sayson, Jorge, Shaklan, Stuart, Riggs, A. J. E., Mawet, Dimitri, Ruane, Garreth, Jovanovic, Nemanja, Echeverri, Daniel, Shaklan, Stuart B., Coker, Carl T., Llop Sayson, Jorge, Shaklan, Stuart, Riggs, A. J. E., Mawet, Dimitri, Ruane, Garreth, Jovanovic, Nemanja, and Echeverri, Daniel

Abstract

Using single-mode fibers (SMFs) in the image plane of coronagraphs allows access to a new wavefront control regime. By using deformable mirrors to create a mismatch between the incoming starlight and the fiber mode, SMFs can serve as integral parts of the light suppression ability of the coronagraph. Previous promising simulation results show increased spectral bandwidth and throughput when using SMFs in a multi-object role, and previous laboratory results have shown increased light suppression using a single SMF. We present an update on efforts to combine a multi-core SMF with a high-resolution spectrograph on the High Contrast Testbed for Segmented Telescopes (HCST) at Caltech. We present our planned experimental design, as well as simulations of expected performance when controlling multiple fiber cores on HCST. We will test the potential increase in spectral bandpass and throughput resulting from the switch to SMFs, as well as the stability of the wavefront control solution.

Published
2019

10. Mushy-layer dynamics in micro and hyper gravity

Author

O'Rourke, J. G., Riggs, A. J. E., Guertler, C. A., Miller, P. W., Padhi, C. M., Popelka, M. M., Wells, A. J., West, A. C., Zhong, J. -Q, Wettlaufer, John S., O'Rourke, J. G., Riggs, A. J. E., Guertler, C. A., Miller, P. W., Padhi, C. M., Popelka, M. M., Wells, A. J., West, A. C., Zhong, J. -Q, and Wettlaufer, John S.

Abstract

We describe the results of experiments on mushy layers grown from aqueous ammonium chloride solution in normal, micro, and hyper gravity environments. In the fully developed chimney state, the chimney plume dynamics differ strikingly when conditions change from micro to hyper gravity. In microgravity, we find fully arrested plume motion and suppressed convection. As gravity exceeds Earth conditions, we observe a host of phenomena, ranging from arched plumes that undergo forced Rayleigh-Taylor instabilities to in-phase multiple plume oscillatory behavior. For the same initial solute concentrations and fixed boundary cooling temperatures, we find that, in runs of over two hours, the averaged effects of microgravity and hypergravity result in suppressed growth of the mushy layers, a phenomenon caused by a net enhancement of convective heat and solute transport from the liquid to the mushy layers. These behaviors are placed in the context of the theory of convecting mushy layers as studied under normal laboratory conditions., AuthorCount:10

Published
2012
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