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Your search keyword '"Institut de Recherche sur les Exoplanètes (iREX)"' showing total 7 results
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7 results on '"Institut de Recherche sur les Exoplanètes (iREX)"'

1. The JCMT BISTRO Survey: Evidence for Pinched Magnetic Fields in Quiescent Filaments of NGC 1333

Author

Doi, Yasuo, Tomisaka, Kohji, Hasegawa, Tetsuo, Coudé, Simon, Arzoumanian, Doris, Bastien, Pierre, Matsumura, Masafumi, Tahani, Mehrnoosh, Sadavoy, Sarah, Hull, Charles L. H., Johnstone, Doug, Di Francesco, James, Shimajiri, Yoshito, Furuya, Ray S., Kwon, Jungmi, Tamura, Motohide, Ward-Thompson, Derek, Le Gouellec, Valentin J. M., Hoang, Thiem, Kirchschlager, Florian, Hwang, Jihye, Eswaraiah, Chakali, Koch, Patrick M., Whitworth, Anthony P., Pattle, Kate, Kwon, Woojin, Kang, Jihyun, Inutsuka, Shu-ichiro, Bourke, Tyler L., Tang, Xindi, Fanciullo, Lapo, Lee, Chang Won, Liu, Hong-Li, Lyo, A-Ran, Qiu, Keping, Lai, Shih-Ping, Department of Earth Science and Astronomy, The University of Tokyo (UTokyo), National Astronomical Observatory of Japan (NAOJ), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), 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), Université de Montréal (UdeM), Institut de Recherche sur les Exoplanètes (iREX), Kagawa University [Japan], National Research Council of Canada (NRC), Queen's University [Kingston, Canada], NRC Herzberg Astronomy and Astrophysics, Conseil National de Recherches Canada (CNRC), Tokushima University, Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Agence Spatiale Européenne = European Space Agency (ESA), Korea Astronomy and Space Science Institute (KASI), University College of London [London] (UCL), Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Academia Sinica, School of Physics and Astronomy [Cardiff], Cardiff University, Seoul National University [Seoul] (SNU), Nagoya City University [Nagoya, Japan], Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester [Manchester], Xinjiang Astronomical Observatory, Chinese Academy of Sciences [Beijing] (CAS), Yunnan Agricultural University, Nanjing University of Aeronautics and Astronautics [Nanjing] (NUAA), and National Tsing Hua University [Hsinchu] (NTHU)

Subjects
interstellar medium, Interstellar filaments (842), FOS: Physical sciences, Astronomy and Astrophysics, F500, Submillimeter astronomy (1647), Astrophysics::Cosmology and Extragalactic Astrophysics, submillimeter astronomy, Interstellar magnetic fields (845), Astrophysics - Astrophysics of Galaxies, star formation, interstellar magnetic fields, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), interstellar filaments, Polarimetry (1278), Star formation (1569), Interstellar medium (847), Astrophysics::Galaxy Astrophysics, polarimetry
Abstract

We investigate the internal 3D magnetic structure of dense interstellar filaments within NGC 1333 using polarization data at $850 \mu\mathrm{m}$ from the $B$-fields In STar-forming Region Observations survey at the James Clerk Maxwell Telescope. Theoretical models predict that the magnetic field lines in a filament will tend to be dragged radially inward (i.e., pinched) toward the central axis due to the filament's self-gravity. We study the cross-sectional profiles of the total intensity ($I$) and polarized intensity (PI) of dust emission in four segments of filaments unaffected by local star formation that are expected to retain a pristine magnetic field structure. We find that the filaments' FWHM in PI are not the same as those in $I$, with two segments being appreciably narrower in PI (FWHM ratio $\simeq 0.7-0.8$) and one segment being wider (FWHM ratio $\simeq 1.3$). The filament profiles of the polarization fraction ($P$) do not show a minimum at the spine of the filament, which is not in line with an anticorrelation between $P$ and $I$ normally seen in molecular clouds and protostellar cores. Dust grain alignment variation with density cannot reproduce the observed $P$ distribution. We demonstrate numerically that the $I$ and PI cross-sectional profiles of filaments in magnetohydrostatic equilibrium will have differing relative widths depending on the viewing angle. The observed variations of FWHM ratios in NGC 1333 are therefore consistent with models of pinched magnetic field structures inside filaments, and especially if they are magnetically near-critical or supercritical., Comment: Accepted for publication in ApJL

Published
2021

2. TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data

Author

Isabelle Boisse, Greg Olmschenk, Nicholas M. Law, P. Guerra, Jessie L. Christiansen, Michael B. Lund, A. Santerne, Ward S. Howard, Richard P. Schwarz, Roland Vanderspek, Jon M. Jenkins, Steve Majewski, Joshua E. Schlieder, Mitchell Yenawine, Samuel N. Quinn, K. I. Collins, Brian P. Powell, Eric B. Ting, Joshua N. Winn, Avi Shporer, John F. Kielkopf, Ravi Kumar Kopparapu, Robert M. Quimby, Jason F. Rowe, Caleb Ben Christiansen, Ethan Kruse, Eric L. N. Jensen, Michael Fausnaugh, Matthew R. Standing, David Wood, Nader Haghighipour, Phillip J. MacQueen, David R. Ciardi, Guillaume Hébrard, Coel Hellier, Denise C. Stephens, Knicole D. Colón, Robert F. Wilson, David J. James, Pat Boyce, Serge Bergeron, Thomas Barclay, Allyson Bieryla, Guillermo Torres, Jeffrey Herman, Elisa V. Quintana, Tsevi Mazeh, Matthew J. Nelson, Dennis M. Conti, Thomas G. Beatty, Karen A. Collins, William F. Welsh, Douglas A. Caldwell, George R. Ricker, Amaury H. M. J. Triaud, Eric Agol, Joshua Pepper, S. Otero, Keivan G. Stassun, Laurance R. Doyle, Edward Wiley, Scott Dixon, Sara Seager, Daniel J. Stevens, Magali Deleuil, David W. Latham, Robert Buchheim, Eric G. Hintz, Michael Endl, Veselin B. Kostov, Jerome A. Orosz, David P. Martin, Benjamin T. Montet, Bradley S. Walter, Lalitha Sairam, Gábor Fűrész, Richard C. Kidwell, Pierre F. L. Maxted, Joseph E. Rodriguez, Gongjie Li, Joe Ulowetz, Jack J. Lissauer, Michael Richmond, Emily A. Gilbert, Felipe Murgas, Billy Quarles, William D. Cochran, Stephen R. Kane, McDonald Observatory, University of Texas at Austin [Austin], Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Georgia Institute of Technology [Atlanta], Institute for Astronomy [Honolulu], University of Hawai‘i [Mānoa] (UHM), University of Washington [Seattle], NASA Goddard Space Flight Center (GSFC), Universities Space Research Association (USRA), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), Institut de Recherche sur les Exoplanètes (iREX), Université de Montréal (UdeM), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Harvard University [Cambridge]-Smithsonian Institution, Institut de Recherche Mathématique de Rennes (IRMAR), Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Nutrition, Métabolismes et Cancer (NuMeCan), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Genève (UNIGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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
Exoplanet astronomy, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Q1, Planet, Eclipsing binary stars, Binary star, QB460, Exoplanet detection methods, QA, QC, ComputingMilieux_MISCELLANEOUS, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Exoplanets, Astronomy, Astronomy and Astrophysics, Exoplanet, Space and Planetary Science, Circumbinary planet, QB799, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the first discovery of a transiting circumbinary planet detected from a single sector of TESS data. During Sector 21, the planet TIC 172900988b transited the primary star and then 5 days later it transited the secondary star. The binary is itself eclipsing, with a period of P = 19.7 days and an eccentricity of e = 0.45. Archival data from ASAS-SN, Evryscope, KELT, and SuperWASP reveal a prominent apsidal motion of the binary orbit, caused by the dynamical interactions between the binary and the planet. A comprehensive photodynamical analysis of the TESS, archival and follow-up data yields stellar masses and radii of M1 = 1.2384 +/- 0.0007 MSun and R1 = 1.3827 +/- 0.0016 RSun for the primary and M2 = 1.2019 +/- 0.0007 MSun and R2 = 1.3124 +/- 0.0012 RSun for the secondary. The radius of the planet is R3 = 11.25 +/- 0.44 REarth (1.004 +/- 0.039 RJup). The planet's mass and orbital properties are not uniquely determined - there are six solutions with nearly equal likelihood. Specifically, we find that the planet's mass is in the range of 824 < M3 < 981 MEarth (2.65 < M3 < 3.09 MJup), its orbital period could be 188.8, 190.4, 194.0, 199.0, 200.4, or 204.1 days, and the eccentricity is between 0.02 and 0.09. At a V = 10.141 mag, the system is accessible for high-resolution spectroscopic observations, e.g. Rossiter-McLaughlin effect and transit spectroscopy., 57 pages, 30 figures, 25 tables; Accepted AJ

Published
2021

3. An Exo-Kuiper Belt and An Extended Halo around HD 191089 in Scattered Light

Author

Pauline Arriaga, Bin Ren, Sloane Wiktorowicz, Alexandra Z. Greenbaum, Rémi Soummer, Arthur Vigan, Christophe Pinte, Robert J. De Rosa, Inseok Song, Laurent Pueyo, Jean-Baptiste Ruffio, Johan Mazoyer, Fredrik T. Rantakyrö, Juan Sebastián Bruzzone, Thomas M. Esposito, Tara Cotten, Patrick Ingraham, Travis Barman, Christopher C. Stark, Sandrine Thomas, J. Kent Wallace, Magaret Moerchen, Jeffrey Chilcote, Julien Rameau, Franck Marchis, Adam C. Schneider, Megan Ansdell, Malena Rice, Christian Marois, Li-Wei Hung, Stanimir Metchev, Lisa Poyneer, Bruce Macintosh, Charles A. Poteet, S. Mark Ammons, René Doyon, James E. Larkin, Kimberly Ward-Duong, Tushar Mittal, Pascale Hibon, Gaspard Duchene, Michael P. Fitzgerald, Quinn Konopacky, Maxwell A. Millar-Blanchaer, Glenn Schneider, Joanna Bulger, Jérôme Maire, Mamadou N'Diaye, Katherine B. Follette, Rebecca Oppenheimer, J. Brendan Hagan, James R. Graham, Eric L. Nielsen, Marie Ygouf, Christine Chen, Paul Kalas, Jennifer Patience, Abhijith Rajan, Marshall D. Perrin, Stephen J. Goodsell, Schuyler Wolff, Anand Sivaramakrishnan, Dean C. Hines, Vanessa P. Bailey, Dmitry Savransky, Elodie Choquet, D. M. Palmer, John H. Debes, Jason J. Wang, Francois Menard, Dominic M. Ryan, Colin Norman, Benjamin L. Gerard, Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Department of Mathematics and Statistics [Baltimore], Loyola University [Maryland, Baltimore], Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Space Telescope Science Institute (STSci), Department of Astronomy [Berkeley], University of California [Berkeley], University of California-University of California, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Yale University [New Haven], Steward Observatory, University of Arizona, Lawrence Livermore National Laboratory (LLNL), Department of Physics and Astronomy [UCLA, Los Angeles], University of California [Los Angeles] (UCLA), Lunar and Planetary Laboratory [Tucson] (LPL), University of Western Ontario (UWO), Subaru Telescope, National Astronomical Observatory of Japan (NAOJ), University of Notre Dame [Indiana] (UND), University of Georgia [USA], Institut de Recherche sur les Exoplanètes (iREX), Université de Montréal [Montréal], Amherst College, Gemini Observatory [Southern Operations Center], Association of Universities for Research in Astronomy (AURA), University of Victoria [Canada] (UVIC), National Research Council of Canada (NRC), Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Natural Sounds and Night Skies Division, Large Synoptic Survey Telescope (LSST), Search for Extraterrestrial Intelligence Institute (SETI), University of California [San Diego] (UC San Diego), University of California, Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford University [Stanford], Department of Physics and Astronomy [Stony Brook], Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), Department of Earth and Planetary Science [UC Berkeley] (EPS), American Geophysical Union, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), American Museum of Natural History (AMNH), Arizona State University [Tempe] (ASU), School of Physics and Astronomy [Clayton], Monash University [Clayton], Department of Astronomy [Ithaca], Cornell University, Department of Astronomy and Astrophysics [UCSC Santa Cruz], University of California [Santa Cruz] (UCSC), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Infrared Processing and Analysis Center (IPAC), 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), NASA-California Institute of Technology (CALTECH), 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]), Université de Montréal (UdeM), Stanford University, 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), Cornell University [New York], University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), University of California (UC), American Geophysical Union [Washington], Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), University of California [Santa Cruz] (UC Santa Cruz), and Universiteit Leiden

Subjects
010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Phase (waves), FOS: Physical sciences, techniques: image processing, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Ring (chemistry), stars: individual (HD 191089), 01 natural sciences, Power law, 0103 physical sciences, 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, Range (particle radiation), Scattering, protoplanetary disks, Astronomy and Astrophysics, stars: imaging, Astrophysics - Solar and Stellar Astrophysics, radiative transfer, 13. Climate action, Space and Planetary Science, Halo, Astrophysics::Earth and Planetary Astrophysics, Intensity (heat transfer), Astrophysics - Earth and Planetary Astrophysics
Abstract

We have obtained Hubble Space Telescope STIS and NICMOS, and Gemini/GPI scattered light images of the HD 191089 debris disk. We identify two spatial components: a ring resembling Kuiper Belt in radial extent (FWHM: ${\sim}$25 au, centered at ${\sim}$46 au), and a halo extending to ${\sim}$640 au. We find that the halo is significantly bluer than the ring, consistent with the scenario that the ring serves as the "birth ring" for the smaller dust in the halo. We measure the scattering phase functions in the 30{\deg}-150{\deg} scattering angle range and find the halo dust is both more forward- and backward-scattering than the ring dust. We measure a surface density power law index of -0.68${\pm}$0.04 for the halo, which indicates the slow-down of the radial outward motion of the dust. Using radiative transfer modeling, we attempt to simultaneously reproduce the (visible) total and (near-infrared) polarized intensity images of the birth ring. Our modeling leads to mutually inconsistent results, indicating that more complex models, such as the inclusion of more realistic aggregate particles, are needed., Comment: 29 pages, 18 figures, ApJ accepted

Published
2019

4. SPIRou input catalogue: activity, rotation and magnetic field of cool dwarfs

Author

Eder Martioli, Andoni Torres‐rivas, Élodie M. Hébrard, René Doyon, Étienne Artigau, Julien Morin, Lison Malo, C. Moutou, Pascal Fouqué, X. Delfosse, Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), 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), York University [Toronto], Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Exoplanètes (iREX), Université de Montréal (UdeM), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke (UdeS), Laboratório Nacional de Astrofísica, 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]), SPIRou Legacy Survey, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), 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), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Montréal [Montréal], Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke [Sherbrooke], Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, symbols.namesake, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Chromosphere, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Zeeman effect, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, Astronomy and Astrophysics, individual: GJ 1289, planet search-stars, Magnetic field, Radial velocity, low-mass stars, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, radial velocity, symbols, Astrophysics::Earth and Planetary Astrophysics, GJ 251, GJ 793, Astrophysics - Earth and Planetary Astrophysics
Abstract

Based on optical high-resolution spectra obtained with CFHT/ESPaDOnS, we present new measurements of activity and magnetic field proxies of 442 low-mass K5-M7 dwarfs. The objects were analysed as potential targets to search for planetary-mass companions with the new spectropolarimeter and high-precision velocimeter, SPIRou. We have analysed their high-resolution spectra in an homogeneous way: circular polarisation, chromospheric features, and Zeeman broadening of the FeH infrared line. The complex relationship between these activity indicators is analysed: while no strong connection is found between the large-scale and small-scale magnetic fields, the latter relates with the non-thermal flux originating in the chromosphere. We then examine the relationship between various activity diagnostics and the optical radial-velocity jitter available in the literature, especially for planet host stars. We use this to derive for all stars an activity merit function (higher for quieter stars) with the goal of identifying the most favorable stars where the radial-velocity jitter is low enough for planet searches. We find that the main contributors to the RV jitter are the large-scale magnetic field and the chromospheric non-thermal emission. In addition, three stars (GJ 1289, GJ 793, and GJ 251) have been followed along their rotation using the spectropolarimetric mode, and we derive their magnetic topology. These very slow rotators are good representatives of future SPIRou targets. They are compared to other stars where the magnetic topology is also known. The poloidal component of the magnetic field is predominent in all three stars., to be published in MNRAS

Published
2017

5. Time-series Analysis of Broadband Photometry of Neptune from K2

Author

Victor Silva Aguirre, François-Xavier Schmider, Patrick Gaulme, John E. Gizis, Sarah L. Casewell, Jason F. Rowe, Heidi B. Hammel, Knicole D. Colón, Mark S. Marley, Michael R. Haas, Othman Benomar, Rafael A. García, Jonathan J. Fortney, Benoit Mosser, Enrico Corsaro, William J. Chaplin, Thomas Barclay, Douglas A. Caldwell, Patrick Boumier, G. R. Davies, Jack J. Lissauer, Amy Simon, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Psychology, St John's University, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), University of California [Santa Cruz] (UCSC), University of California, Research institute of Computer Vision and Robotics [Girona] (VICOROB), Universitat de Girona (UdG), University of Delaware [Newark], Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Exoplanètes (iREX), Université de Montréal (UdeM), New Mexico State University, Apache point observatory, NASA Goddard Space Flight Center (GSFC), Association of Universities for Research in Astronomy (AURA), Stellar Astrophysics Centre [Aarhus] (SAC), Aarhus University [Aarhus], Bay Area Environmental Research Institute (BAER), NYUAD Center for Space Science, New York University [Abu Dhabi], NYU System (NYU)-NYU System (NYU), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Search for Extraterrestrial Intelligence Institute (SETI), Department of Physics and Astronomy [Leicester], University of Leicester, School of Physics and Astronomy [Birmingham], University of Birmingham [Birmingham], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Universidad de La Laguna [Tenerife - SP] (ULL), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and European Project: 267864,EC:FP7:ERC,ERC-2010-AdG_20100224,ASTERISK(2011)

Subjects
gaseous planets [planets and satellites], 010504 meteorology & atmospheric sciences, FOS: Physical sciences, 01 natural sciences, Photometry (optics), Neptune, Planet, 0103 physical sciences, Broadband, Astrophysics::Solar and Stellar Astrophysics, Time series, 010303 astronomy & astrophysics, planetary systems, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Spacecraft, business.industry, Astronomy, Astronomy and Astrophysics, planets and satellites: gaseous planets, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, Solar variation
Abstract

We report here on our search for excess power in photometry of Neptune collected by the K2 mission that may be due to intrinsic global oscillations of the planet Neptune. To conduct this search, we developed new methods to correct for instrumental effects such as intrapixel variability and gain variations. We then extracted and analyzed the time-series photometry of Neptune from 49 days of nearly continuous broadband photometry of the planet. We find no evidence of global oscillations and place an upper limit of $\sim$5 ppm at 1000 \uhz\ for the detection of a coherent signal. With an observed cadence of 1-minute and point-to-point scatter less than 0.01\%, the photometric signal is dominated by reflected light from the Sun, which is in turn modulated by atmospheric variability of Neptune at the 2\% level. A change in flux is also observed due to the increasing distance between Neptune and the K2 spacecraft, and solar variability with convection-driven solar p modes present., Comment: 31 pages, 6 figure, accepted for publication in AJ

Published
2017

6. Confirmation of the radial velocity super-Earth K2-18c with HARPS and CARMENES

Author

A. Wünsche, Francesco Pepe, Michel Mayor, Nuno C. Santos, Nicola Astudillo-Defru, Xavier Bonfils, Stéphane Udry, Felipe Murgas, François Bouchy, René Doyon, T. Forveille, Kristen Menou, X. Delfosse, C. Lovis, Ryan Cloutier, Jose-Manuel Almenara, Université du Québec à Rimouski (UQAR), Institut de Recherche sur les Exoplanètes (iREX), Université de Montréal (UdeM), Universidad de Concepción [Chile], 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]), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto [Porto], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Universidade do Porto

Subjects
planets and satellites: detection, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, 01 natural sciences, Signal, fundamental parameters -planets and satellites, Planet, radial velocities -planets and satellites, techniques: radial velocities, 0103 physical sciences, individual, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, Spectrograph, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, K2-18, Super-Earth, Astronomy and Astrophysics, planets and satellites: individual: K2-18, Planetary system, data analysis -planets and satellites, methods: data analysis, Radial velocity, detectionmethods, Wavelength, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, techniques, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

In an earlier campaign to characterize the mass of the transiting temperate super-Earth K2-18b with HARPS, a second, non-transiting planet was posited to exist in the system at $\sim 9$ days. Further radial velocity follow-up with the CARMENES spectrograph visible channel revealed a much weaker signal at 9 days which also appeared to vary chromatically and temporally leading to the conclusion that the origin of the 9 day signal was more likely to be related to stellar activity than to being planetary. Here we conduct a detailed re-analysis of all available RV time-series, including a set of 31 previously unpublished HARPS measurements, to investigate the effects of time-sampling and of simultaneous modelling of planetary + activity signals on the existence and origin of the curious 9 day signal. We conclude that the 9 day signal is real and was initially seen to be suppressed in the CARMENES data due to a small number of anomalous measurements, although the exact cause of these anomalies remains unknown. Investigation of the signal's evolution in time, with wavelength, and detailed model comparison reveals that the 9 day signal is most likely planetary in nature. By this analysis, we reconcile the conflicting HARPS and CARMENES results and measure precise and self-consistent planet masses of $m_{p,b} = 8.63 \pm 1.35$ and $m_{p,c}\sin{i_c}=5.62 \pm 0.84$ M$_{\oplus}$. This work, along with the previously published RV papers on the K2-18 planetary system, highlight the importance of understanding one's time-sampling and of simultaneous planet + stochastic activity modelling, particularly when searching for sub-Neptune-sized planets with radial velocities., 19 pages, 10 figures (including 9 interactive figures when viewed in Adobe Acrobat), accepted for publication in Astronomy & Astrophysics

Published
2019

7. Asymmetry in the triplet 3p-4s Mg lines in cool DZ white dwarfs

Author

Thierry Leininger, V. Brousseau-Couture, Nicole Allard, Patrick Dufour, Florent Xavier Gadéa, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Département de Physique [Montréal], Université de Montréal (UdeM), Institut de Recherche sur les Exoplanètes (iREX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse)

Subjects
Physics, media_common.quotation_subject, Ab initio, chemistry.chemical_element, White dwarf, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Potential energy, Asymmetry, Spectral line, Wavelength, chemistry, Space and Planetary Science, 0103 physical sciences, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Helium, media_common, Line (formation)
Abstract

7 pages; International audience; The purpose of the present work is to make an exhaustive study of the line shape of the triplet 3p-4s Mg line (Mgb triplet), which is perturbed by He in the extreme physical conditions found in the cool atmosphere of DZ white dwarfs. This study is undertaken by inferring both a unified theory of spectral line broadening and ab initio potential energies. Cool white dwarfs require a specific treatment for line broadening owing to the high helium densities that are involved. Beyond the conventional symmetrical Lorentzian core at low density, we show that the line profiles are asymmetrical and have significant additional contributions on the short wavelength side. This blue asymmetry is a consequence of low maxima in the corresponding Mg-He potential energy difference curves at short and intermediate internuclear distances. The new profiles are shown to provide a good fit to an SDSS (Sloan Digital Sky Survey) observation.

Published
2016

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