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Your search keyword '"Lynne Hillenbrand"' showing total 4 results
Start Over Author "Lynne Hillenbrand" Topic astrophysics::galaxy astrophysics
4 results on '"Lynne Hillenbrand"'

1. Building galaxies, stars, planets and the ingredients for life between the stars. The science behind the European Ultraviolet-Visible Observatory

Author

Ana I. Gómez de Castro, Thierry Appourchaux, Martin A. Barstow, Mathieu Barthelemy, Frederic Baudin, Stefano Benetti, Pere Blay, Noah Brosch, Emma Bunce, Domitilla de Martino, Jean-Michel Deharveng, Roger Ferlet, Kevin France, Miriam García, Boris Gänsicke, Cecile Gry, Lynne Hillenbrand, Eric Josselin, Carolina Kehrig, Laurent Lamy, Jon Lapington, Alain Lecavelier des Etangs, Frank LePetit, Javier López-Santiago, Bruno Milliard, Richard Monier, Giampiero Naletto, Yael Nazé, Coralie Neiner, Jonathan Nichols, Marina Orio, Isabella Pagano, Céline Peroux, Gregor Rauw, Steven Shore, Marco Spaans, Gagik Tovmassian, Asif ud-Doula, José Vilchez, Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), 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), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-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 Joseph Fourier - Grenoble 1 (UJF)-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), The Wise Observatory and The Raymond & Beverly Sackler School of Physics and Astronomy, Tel Aviv University [Tel Aviv], 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 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), Center for Astrophysics and Space Astronomy [Boulder] (CASA), University of Colorado [Boulder], Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), Groupe de Recherche en Astronomie et Astrophysique du Languedoc (GRAAL), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre de Recherche en Économie et Statistique (CREST), Ecole Nationale de la Statistique et de l'Analyse de l'Information [Bruz] (ENSAI)-École polytechnique (X)-École Nationale de la Statistique et de l'Administration Économique (ENSAE Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Pennsylvania State University (Penn State), Penn State System, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-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 Joseph Fourier - Grenoble 1 (UJF)-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)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Tel Aviv University (TAU), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Padova = University of Padua (Unipd), and Kapteyn Astronomical Institute

Subjects
Solar System, 7. Clean energy, Ultraviolet: solar system, Astrobiology, Instrumentation: telescopes, Observatory, Planet, Astrophysics::Solar and Stellar Astrophysics, Ultraviolet: general, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Ultraviolet: ISM, Planetary habitability, Astronomy and Astrophysics, Planetary system, Exoplanet, Galaxy, Ultraviolet: stars, 13. Climate action, Space and Planetary Science, Ultraviolet: galaxies, Extraterrestrial life, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Instrumentation: miscellaneous
Abstract

This contribution gathers the contents of the white paper submitted by the UV community to the Call issued by the European Space Agency in March 2013, for the definition of the L2 and L3 missions in the ESA science program. We outlined the key science that a large UV facility would make possible and the instrumentation to be implemented. The growth of luminous structures and the building blocks of life in the Universe began as primordial gas was processed in stars and mixed at galactic scales. The mechanisms responsible for this development are not well-understood and have changed over the intervening 13 billion years. To follow the evolution of matter over cosmic time, it is necessary to study the strongest (resonance) transitions of the most abundant species in the Universe. Most of them are in the ultraviolet (UV; 950 Å–3000 Å) spectral range that is unobservable from the ground. A versatile space observatory with UV sensitivity a factor of 50–100 greater than existing facilities will revolutionize our understanding of the Universe. Habitable planets grow in protostellar discs under ultraviolet irradiation, a by-product of the star-disk interaction that drives the physical and chemical evolution of discs and young planetary systems. The electronic transitions of the most abundant molecules are pumped by this UV field, providing unique diagnostics of the planet-forming environment that cannot be accessed from the ground. Earth’s atmosphere is in constant interaction with the interplanetary medium and the solar UV radiation field. A 50–100 times improvement in sensitivity would enable the observation of the key atmospheric ingredients of Earth-like exoplanets (carbon, oxygen, ozone), provide crucial input for models of biologically active worlds outside the solar system, and provide the phenomenological baseline to understand the Earth atmosphere in context.

Published
2014
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2. Stellar Age Estimation from 3 Myr to 3 Gyr

Author

Lynne Hillenbrand, Eric Mamajek, John Stauffer, David Soderblom, John Carpenter, Michael Meyer, Eric Stempels, and Stempels, Eric

Subjects
Physics, Astrophysics (astro-ph), FOS: Physical sciences, myr, Astrophysics, Stellar age estimation, Stars, Age estimation, Physics::Space Physics, Random error, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present recent progress on quantitative estimation of stellar ages using ind icators such as theoretical evolutionary tracks, rotation, rotation-driven chrom ospheric and coronal activity, and lithium depletion. Our focus is on roughly so lar-mass and solar-metallicity stars younger than the Sun. We attempt to charac terize the systematic and random error sources and then derive "best" ages alo ng with the dispersion in age arising among the various age estimation methods. Our main application of these techniques is to the evolution of debris disks., Comment: 4 pages; to appear in "Cool Stars XV" published by AIP Conference Series (online only)

Published
2009
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3. DIRECT MEASUREMENT OF INTERSTELLAR EXTINCTION TOWARD YOUNG STARS USING ATOMIC HYDROGEN Lyα ABSORPTION

Author

Matthew McJunkin, Kevin France, P. C. Schneider, Gregory J. Herczeg, Alexander Brown, Lynne Hillenbrand, Rebecca N. Schindhelm, and Suzan Edwards

Subjects
Physics, Line-of-sight, Astrophysics::High Energy Astrophysical Phenomena, Extinction (astronomy), Astronomy and Astrophysics, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Protoplanetary disk, Astrophysics - Astrophysics of Galaxies, T Tauri star, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Protoplanet, Absorption (electromagnetic radiation), Astrophysics::Galaxy Astrophysics
Abstract

Interstellar reddening corrections are necessary to reconstruct the intrinsic spectral energy distributions (SEDs) of accreting protostellar systems. The stellar SED determines the heating and chemical processes that can occur in circumstellar disks. Measurement of neutral hydrogen absorption against broad Lyman-$\alpha$ emission profiles in young stars can be used to obtain the total H I column density (N(H I)) along the line of sight. We measure N(H I) with new and archival ultraviolet observations from the Hubble Space Telescope ($HST$) of 31 classical T Tauri and Herbig Ae/Be stars. The H I column densities range from log$_{10}$(N(H I)) $\approx 19.6 - 21.1$, with corresponding visual extinctions of A$_{V}$ $= 0.02 - 0.72$ mag, assuming an R$_{V}$ of 3.1. We find that the majority of the H I absorption along the line of sight likely comes from interstellar rather than circumstellar material. Extinctions derived from new $HST$ blue-optical spectral analyses, previous IR and optical measurements, and new X-ray column densities on average overestimate the interstellar extinction toward young stars compared to the N(H I) values by $\sim 0.6$ mag. We discuss possible explanations for this discrepancy in the context of a protoplanetary disk geometry., Comment: 20 pages, 10 figures

Published
2013
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4. NEAR-ULTRAVIOLET EXCESS IN SLOWLY ACCRETING T TAURI STARS: LIMITS IMPOSED BY CHROMOSPHERIC EMISSION

Author

Laura Ingleby, Nuria Calvet, Edwin Bergin, Gregory Herczeg, Alexander Brown, Richard Alexander, Suzan Edwards, Catherine Espaillat, Kevin France, Scott G. Gregory, Lynne Hillenbrand, Evelyne Roueff, Jeff Valenti, Frederick Walter, Christopher Johns-Krull, Joanna Brown, Jeffrey Linsky, Melissa McClure, David Ardila, Hervé Abgrall, Thomas Bethell, Gaitee Hussain, and Hao Yang

Subjects
Physics, Cosmic Origins Spectrograph, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Photoevaporation, Accretion (astrophysics), Stars, T Tauri star, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Emission spectrum, 010303 astronomy & astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics, Space Telescope Imaging Spectrograph
Abstract

Young stars surrounded by disks with very low mass accretion rates are likely in the final stages of inner disk evolution and therefore particularly interesting to study. We present ultraviolet (UV) observations of the ~5-9 Myr old stars RECX-1 and RECX-11, obtained with the Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph on the Hubble Space Telescope, as well as optical and near-infrared spectroscopic observations. The two stars have similar levels of near-UV emission, although spectroscopic evidence indicates that RECX-11 is accreting and RECX-1 is not. The line profiles of Hα and He I λ10830 in RECX-11 show both broad and narrow redshifted absorption components that vary with time, revealing the complexity of the accretion flows. We show that accretion indicators commonly used to measure mass accretion rates, e.g., U-band excess luminosity or the Ca II triplet line luminosity, are unreliable for low accretors, at least in the middle K spectral range. Using RECX-1 as a template for the intrinsic level of photospheric and chromospheric emission, we determine an upper limit of 3 × 10^(–10) M_☉ yr–1 for RECX-11. At this low accretion rate, recent photoevaporation models predict that an inner hole should have developed in the disk. However, the spectral energy distribution of RECX-11 shows fluxes comparable to the median of Taurus in the near-infrared, indicating that substantial dust remains. Fluorescent H2 emission lines formed in the innermost disk are observed in RECX-11, showing that gas is present in the inner disk, along with the dust.

Published
2011
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