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101. Stellar activity of planetary host star HD 189733

Author: François Bouchy, Nuno C. Santos, Isabelle Boisse, Jason F. Rowe, C. Lovis, Jaymie M. Matthews, C. Perrier, D. Queloz, G. Hebrard, Anne-Marie Lagrange, D. Segransan, Stéphane Udry, B. Loeillet, T. Forveille, Francesco Pepe, C. Moutou, Alfred Vidal-Madjar, M. Mayor, M. Desort, X. Bonfils, Bryce Croll, Frederic Pont, X. Delfosse, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010308 nuclear & particles physics, Stellar rotation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Orbital period, 01 natural sciences, Spectral line, Radial velocity, Orbit, Space and Planetary Science, Planet, 0103 physical sciences, Orbital motion, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Planetary mass
Abstract: Extra-solar planet search programs require high-precision velocity measurements. They need to study how to disentangle radial-velocity variations due to Doppler motion from the noise induced by stellar activity. We monitored the active K2V star HD 189733 and its transiting planetary companion that has a 2.2-day orbital period. We used the high-resolution spectograph SOPHIE mounted on the 1.93-m telescope at the Observatoire de Haute-Provence to obtain 55 spectra of HD 189733 over nearly two months. We refined the HD 189733b orbit parameters and put limits on the eccentricity and on a long-term velocity gradient. After subtracting the orbital motion of the planet, we compared the variability of spectroscopic activity indices to the evolution of the radial-velocity residuals and the shape of spectral lines. The radial velocity, the spectral-line profile and the activity indices measured in HeI (5875.62 \AA), Halpha (6562.81 \AA) and the CaII H&K lines (3968.47 \AA and 3933.66 \AA, respectively) show a periodicity around the stellar rotation period and the correlations between them are consistent with a spotted stellar surface in rotation. We used such correlations to correct for the radial-velocity jitter due to stellar activity. This results in achieving high precision on the orbit parameters, with a semi-amplitude K = 200.56 \pm 0.88 m.s-1 and a derived planet mass of M_{P}=1.13 \pm 0.03 M$_{Jup}$., Comment: 9 pages, 2 tables, 9 figures, accepted for publication in A&A on 20/11/2008
Published: 2008
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102. Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud

Author: M. Gros, J. B. Marquette, Y. R. Rahal, E. Maurice, David S. Graff, J. de Kat, Andrew Gould, J. N. Albert, Pascal Fouqué, Alfred Vidal-Madjar, E. Lesquoy, V. Doublier, Patrick Tisserand, J. F. Glicenstein, Ch. Coutures, C. Hamadache, R. Ansari, L. Le Guillou, Roger Ferlet, P. Bareyre, Éric Aubourg, Anaëlle Maury, A. Schwarzenberg-Czerny, M. Moniez, Johannes Andersen, Michel Spiro, J. Pritchard, X. Charlot, J. Haissinski, J. Rich, A. Milsztajn, P. François, C. Magneville, Jean-Philippe Beaulieu, Bertrand Goldman, C. Afonso, Nathalie Palanque-Delabrouille, S. Zylberajch, O. Perdereau, C. Loup, 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), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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), 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), European Southern Observatory (ESO), ANR-06-BLAN-0416,HOLMES,HOLMES (Hunting cOol Low Mass Extrasolar PlanetS)(2006), 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 Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), and 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)
Subjects: Proper motion, Cepheid variable, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Metallicity, FOS: Physical sciences, Astrophysics, Cepheids, 01 natural sciences, Galaxy: disk, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Magellanic Clouds, 010303 astronomy & astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), stars: peculiar, Astronomy and Astrophysics, Astrometry, Light curve, Radial velocity, Space and Planetary Science, Small Magellanic Cloud, Variable star
Abstract: For seven years, the EROS-2 project obtained a mass of photometric data on variable stars. We present a peculiar Cepheid-like star, in the direction of the Small Magellanic Cloud, which demonstrates unusual photometric behaviour over a short time interval. We report on data of the photometry acquired by the MARLY telescope and spectroscopy from the EFOSC instrument for this star, called EROS2 J005135-714459(sm0060n13842), which resembles the unusual Cepheid HR 7308. The light curve of our target is analysed using the Analysis of Variance method to determine a pulsational period of 5.5675 days. A fit of time-dependent Fourier coefficients is performed and a search for proper motion is conducted. The light curve exhibits a previously unobserved and spectacular change in both mean magnitude and amplitude, which has no clear theoretical explanation. Our analysis of the spectrum implies a radial velocity of 104 km s$^{-1}$ and a metallicity of -0.4$\pm$0.2 dex. In the direction of right ascension, we measure a proper motion of 17.4$\pm$6.0 mas yr$^{-1}$ using EROS astrometry, which is compatible with data from the NOMAD catalogue. The nature of EROS2 J005135-714459(sm0060n13842) remains unclear. For this star, we may have detected a non-zero proper motion for this star, which would imply that it is a foreground object. Its radial velocity, pulsational characteristics, and photometric data, however, suggest that it is instead a Cepheid-like object located in the SMC. In such a case, it would present a challenge to conventional Cepheid models., Comment: Correction of typos in the abstract
Published: 2008
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103. The FIRST project: a single-mode fiber-based very high-dynamic range diffraction-limited imaging instrument at visible to near-infrared wavelengths

Author: Sylvestre Lacour, Jean-Philippe Berger, Alain Lecavelier, Pierre Kervella, Takayuki Kotani, Pierre Fedou, Olivier Chesneau, Julien Woillez, Daniel Rouan, Stephen T. Ridgway, Olivier Lai, Pascal Bordé, Guy Perrin, Alfred Vidal-Madjar, Éric Thiébaut, 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, 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), Centre de Recherche Astrophysique de Lyon (CRAL), 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), W. M. Keck Observatory, Institut d'astrophysique spatiale (IAS), 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), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), 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), Sorbonne Université (SU), and National Optical Astronomy Observatory, Tucson (NOAO)
Subjects: Physics, Diffraction, business.industry, Near-infrared spectroscopy, Astrophysics::Instrumentation and Methods for Astrophysics, Single-mode optical fiber, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, Wavelength, Interferometry, Optics, Planet, law, Optoelectronics, Astrophysics::Earth and Planetary Astrophysics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, High dynamic range
Abstract: International audience; We describe the present status of the development of a very high-dynamic range, diffraction limited imaging instrument FIRST (Fibered Imager foR Single Telescope), among which goals is the detection of nearby extra-solar planets at visible to near-infrared wavelengths from the ground. We have started to develop a prototype system which consists of a number of novel designs such as a segmented micro mirror array and silicon micro machined single-mode fiber arrays. Furthermore, we have proposed to build a FIRST instrument for the CFHT, which will be complementary to high-dynamic range instruments developed for 8m class telescopes at near-infrared wavelengths.
Published: 2008
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104. Determining atmospheric conditions at the terminator of the hot-Jupiter HD209458b

Author: David K. Sing, A. Lecavelier des Etangs, Alfred Vidal-Madjar, David Ehrenreich, Jean-Michel Desert, Gilda E. Ballester, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Sodium, FOS: Physical sciences, chemistry.chemical_element, Astrophysics, 01 natural sciences, Molecular physics, Spectral line, Altitude, Ionization, 0103 physical sciences, Hot Jupiter, Physics::Atomic and Molecular Clusters, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Physics, Atmospheric escape, Atmospheric models, Astrophysics (astro-ph), Astronomy and Astrophysics, chemistry, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Thermosphere
Abstract: We present a theoretical model fit to the HST/STIS optical transit transmission spectrum of HD209458b. In our fit, we use the sodium absorption line profile along with the Rayleigh scattering by H_2 to help determine the average temperature-pressure profile at the planetary terminator, and infer the abundances of atomic and molecular species. The observed sodium line profile spans an altitude range of ~3,500 km, corresponding to pressures between ~0.001 and 50 mbar in our atmospheric models. We find that the sodium line profile requires either condensation into sodium sulfide or ionization, necessary to deplete atomic sodium only at high altitudes below pressures of ~3 mbar. The depletion of sodium is supported by an observed sudden abundance change, from 2 times solar abundance in the lower atmosphere to 0.2 solar or lower in the upper atmosphere. Our findings also indicate the presence of a hot atmosphere near stratospheric altitudes corresponding to pressures of 33 mbar, consistent with that of the observed dayside temperature inversion. In addition, we find a separate higher altitude temperature rise is necessary within both the condensation and ionization models, corresponding to pressures below ~0.01 mbar. This hot higher altitude temperature indicates that absorption by atomic sodium can potentially probe the bottom of the thermosphere, and is possibly sensitive to the temperature rise linked to atmospheric escape., 11 pages, 4 figures, accepted to Astrophysical Journal
Published: 2008
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105. ELODIE metallicity-biased search for transiting Hot Jupiters. V. An intermediate-period Jovian planet orbiting HD 45652

Author: Dominique Naef, Isabelle Boisse, François Bouchy, D. Queloz, G. Hebrard, X. Delfosse, Shay Zucker, Frederic Pont, M. Desort, R. da Silva, Anne-Marie Lagrange, Alfred Vidal-Madjar, X. Bonfils, T. Forveille, C. Perrier, D. Segransan, Francesco Pepe, B. Loeillet, C. Moutou, Nuno C. Santos, C. Lovis, M. Mayor, Stéphane Udry, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Metallicity, Astrophysics (astro-ph), Giant planet, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Orbital period, 01 natural sciences, Jovian, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Jupiter mass, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract: We present the detection of a 0.47 Jupiter mass planet in a 44-day period eccentric trajectory (e=0.39) orbiting the metal-rich star HD45652. This planet, the seventh giant planet discovered in the context of the ELODIE metallicity-biased planet search program, is also confirmed using higher precision radial-velocities obtained with the CORALIE and SOPHIE spectrographs. The orbital period of HD45652b places it in the middle of the "gap" in the period distribution of extra-solar planets., 5 pages, 4 figures, Astronomy & Astrophysics, in press; Replaced after minor language corrections and typo correction in Table 3
Published: 2008
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106. Misaligned spin-orbit in the XO-3 planetary system?

Author: Alfred Vidal-Madjar, Thierry Forveille, Nuno C. Santos, Damien Ségransan, C. Perrier, Didier Queloz, Michel Mayor, C. Lovis, Francesco Pepe, Frederic Pont, B. Loeillet, Anne-Marie Lagrange, X. Bonfils, Guillaume Hébrard, Isabelle Boisse, A. Eggenberger, François Bouchy, M. Desort, Markus Rabus, Stéphane Udry, David Ehrenreich, Xavier Delfosse, C. Moutou, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Orbital plane, 530 Physics, FOS: Physical sciences, Orbital eccentricity, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, Spin-½, Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Planetary system, Light curve, Exoplanet, Radial velocity, Orbit, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Orbit (control theory)
Abstract: The transiting extrasolar planet XO-3b is remarkable, with a high mass and eccentric orbit. The unusual characteristics make it interesting to test whether its orbital plane is parallel to the equator of its host star, as it is observed for other transiting planets. We performed radial velocity measurements of XO-3 with the SOPHIE spectrograph at the 1.93-m telescope of Haute-Provence Observatory during a planetary transit, and at other orbital phases. This allowed us to observe the Rossiter-McLaughlin effect and, together with a new analysis of the transit light curve, to refine the parameters of the planet. The unusual shape of the radial velocity anomaly during the transit provides a hint for a nearly transverse Rossiter-McLaughlin effect. The sky-projected angle between the planetary orbital axis and the stellar rotation axis should be lambda = 70 +/- 15 degrees to be compatible with our observations. This suggests that some close-in planets might result from gravitational interaction between planets and/or stars rather than migration due to interaction with the accretion disk. This surprising result requires confirmation by additional observations, especially at lower airmass, to fully exclude the possibility that the signal is due to systematic effects., Comment: 8 pages, 8 figures, 3 tables, to be published in A&A
Published: 2008
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107. Extrasolar Comets

Author: Roger Ferlet, Jérémie Boissier, Alain Lecavelier des Etangs, and Alfred Vidal-Madjar
Published: 2008
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108. Commission 53: Extrasolar Planets

Author: Michel Mayor, Alan P. Boss, Paul R. Butler, William B. Hubbard, Philip A. Ianna, Martin Kürster, Jack J. Lissauer, Karen J. Meech, François Mignard, Alan J. Penny, Andreas Quirrenbach, Jill C. Tarter, Alfred Vidal-Madjar, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), 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, and 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)
Subjects: 010504 meteorology & atmospheric sciences, Space and Planetary Science, 0103 physical sciences, Astronomy and Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Commission 53 on Extrasolar Planets was created at the 2006 Prague General Assembly of the IAU, in recognition of the outburst of astronomical progress in the field of extrasolar planet discovery, characterization, and theoretical work that has occurred since the discovery of the pulsar planets in 1992 and the discovery of the first planet in orbit around a solar-type star in 1995. Commission 53 is the logical successor to the IAU Working Group on Extrasolar Planets WG-ESP, which ended its six years of existence in August 2006. The founding president of Commission 53 is Michael Mayor, in honor of his seminal contributions to this new field of astronomy. The vice-president is Alan Boss, the former chair of the WG-ESP, and the members of the Commission 53 Organizing Committee are the other former members of the WG-ESP.
Published: 2008
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109. Molecular hydrogen in the circumstellar environments of Herbig Ae/Be stars probed by FUSE

Author: C. Martin-Zaidi, Alfred Vidal-Madjar, J. Le Bourlot, Leonardo Testi, A. Lecavelier des Etangs, Cornelis P. Dullemond, Paul D. Feldman, J. C. Bouret, Aki Roberge, Magali Deleuil, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010308 nuclear & particles physics, Be star, Molecular cloud, Photodissociation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Photodissociation region, 01 natural sciences, Spectral line, Interstellar medium, Stars, 13. Climate action, Space and Planetary Science, Excited state, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: We observed molecular hydrogen around a sample of pre-main sequence stars in order to better characterize their gaseous CS environments. We analyzed the FUSE (Far Ultraviolet Spectroscopic Explorer) spectra of a sample of Herbig Ae/Be stars (HAeBes) covering a broad spectral range, including the main-sequence A5 star Beta-Pictoris. To better diagnose the origin of the detected H2 and its excitation conditions, we used a model of a photodissociation region. Our analysis demonstrates that the excitation of H2 is clearly different around most of the HAeBes compared to the interstellar medium. Moreover, the characteristics of H2 around Herbig Ae and Be stars give evidence for different excitation mechanisms. For the most massive stars of our sample (B8 to B2 type), the excitation diagrams are reproduced well by a model of photodissociation regions (PDR). Our results favor an interpretation in terms of large CS envelopes, remnants of the molecular clouds in which the stars were formed. On the other hand, the group of Ae stars (later than B9 type) known to possess disks is more inhomogeneous. In most cases, when CS H2 is detected, the lines of sight do not pass through the disks. The excitation conditions of H2 around Ae stars cannot be reproduced by PDR models and correspond to warm and/or hot excited media very close to the stars. In addition, no clear correlation has been found between the ages of the stars and the amount of circumstellar H2. Our results suggest structural differences between Herbig Ae and Be star environments. Herbig Be stars do evolve faster than Ae stars, and consequently, most Herbig Be stars are younger than Ae ones at the time we observe them. It is thus more likely to find remnants of their parent cloud around them., Comment: 23 pages (including on-line material), accepted for publication in A&A
Published: 2008
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110. R Coronae Borealis stars in the Galactic Bulge discovered by EROS-2

Author: Johannes Andersen, Michel Spiro, Bertrand Goldman, M. Gros, A. Milsztajn, J. N. Albert, Nathalie Palanque-Delabrouille, S. Zylberajch, L. Le Guillou, O. Perdereau, J. de Kat, Anaëlle Maury, P. Bareyre, E. Maurice, Patrick Tisserand, M. Moniez, C. Hamadache, Peter R. Wood, Jean-Philippe Beaulieu, Roger Ferlet, Éric Aubourg, Andrew Gould, J. B. Marquette, R. Ansari, C. Magneville, C. Afonso, J. Rich, Alfred Vidal-Madjar, Y. R. Rahal, Pascal Fouqué, J. F. Glicenstein, Ch. Coutures, X. Charlot, E. Lesquoy, J. Haissinski, C. Loup, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), Département de Physique des Particules (ex SPP) (DPhP), 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, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), APC - Cosmologie, 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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Service Détecteurs (SERVICE DéTECTEURS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), 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), Services communs OMP (UMS 831), 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), European Southern Observatory (ESO), EROS-2, Département de Physique des Particules (ex SPP) (DPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-AstroParticule et Cosmologie (APC (UMR_7164)), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Services communs OMP - UMS 831 (UMS 831), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Toulouse III - Paul Sabatier (UT3), 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), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-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-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and 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)
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Luminosity, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Bulge, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics, Physics, Spiral galaxy, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Stars, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Variable star, Supergiant
Abstract: Rare types of variable star may give unique insight into short-lived stages of stellar evolution. The systematic monitoring of millions of stars and advanced light curve analysis techniques of microlensing surveys make them ideal for discovering also such rare variable stars. One example is the R Coronae Borealis (RCB) stars, a rare type of evolved carbon-rich supergiant. We have conducted a systematic search of the EROS-2 database for the Galactic catalogue Bulge and spiral arms to find Galactic RCB stars. The light curves of $\sim$100 million stars, monitored for 6.7 years (from July 1996 to February 2003), have been analysed to search for the main signature of RCB stars, large and rapid drops in luminosity. Follow-up spectroscopy has been used to confirm the photometric candidates. We have discovered 14 new RCB stars, all in the direction of the Galactic Bulge, bringing the total number of confirmed Galactic RCB stars to about 51. After reddening correction, the colours and absolute magnitudes of at least 9 of the stars are similar to those of Magellanic RCB stars. This suggests that these stars are in fact located in the Galactic Bulge, making them the first RCB stars discovered in the Bulge. The localisation of the 5 remaining RCBs is more uncertain: 4 are either located behind the Bulge at an estimated maximum distance of 14 kpc or have an unusual thick circumstellar shell; the other is a DY Per RCB which may be located in the Bulge, even if it is fainter than the known Magellanic DY Per. From the small scale height found using the 9 new Bulge RCBs, $61, Comment: 20 pages, 26 figures, Accepted in A&A
Published: 2008
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111. Atmospheric composition and structure of HD209458b

Author: Alfred Vidal-Madjar, Guillaume Hébrard, David K. Sing, Roger Ferlet, David Ehrenreich, A. Lecavelier des Etangs, and Jean-Michel Desert
Subjects: Physics, Astrophysics (astro-ph), Broad band, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Spectral line, Atmosphere, Atmospheric composition, symbols.namesake, Space and Planetary Science, Planet, symbols, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Astrophysics::Earth and Planetary Astrophysics, Rayleigh scattering, Spectroscopy, Physics::Atmospheric and Oceanic Physics
Abstract: Transiting planets like HD209458b offer a unique opportunity to scrutinize their atmospheric composition and structure. Transit spectroscopy probes the transition region between the day and night sides, called limb. We present a re-analysis of existing archived HST/STIS transmission spectra of HD209458b's atmosphere. From these observations we: Identify H2 Rayleigh scattering, derive the absolute Sodium abundance and quantify its depletion in the upper atmosphere, extract a stratospheric T-P profile with a temperature inversion and explain broad band absorptions with the presence of TiO and VO molecules in the atmosphere of this planet., Comment: 4 pages, 2 figures. To appear in the Proceedings of the 253rd IAU Symposium: "Transiting Planets", May 2008, Cambridge, MA
Published: 2008
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112. Is there room for changed dark matter?

Author: R. Mochkovitch, J. Rich, J.L. Basdevant, Michel Spiro, and Alfred Vidal-Madjar
Subjects: Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Astrophysics::High Energy Astrophysical Phenomena, Hot dark matter, Dark matter, Scalar field dark matter, Astrophysics::Cosmology and Extragalactic Astrophysics, Halo, Astrophysics, Light dark matter, Charged particle
Abstract: It has recently been suggested that galactic dark matter halos could be made of very heavy charged particles (20–1000 TeV). We show that present observations and experimental limits are hardly compatible with such a scenario. The best chance, if any, would be in the upper mass range near or above 1000 TeV which can be unambiguously explored by specific experiments that we discuss.
Published: 1990
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113. Refined parameters and spectroscopic transit of the super-massive planet HD147506b

Author: Tsevi Mazeh, François Bouchy, Isabelle Boisse, C. Lovis, D. Queloz, N. C. Santos, A. Ecuvillon, T. Forveille, B. Loeillet, X. Delfosse, M. Desort, M. Mayor, A. Shporer, C. Perrier, R. da Silva, Alexandre Gallenne, J. L. Beuzit, Francesco Pepe, G. Hebrard, Stéphane Udry, C. Moutou, D. Segransan, Alfred Vidal-Madjar, Jean-Pierre Sivan, F. Galland, Anne-Marie Lagrange, X. Bonfils, Frederic Pont, Y. Tsodikovich, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Orbital elements, Physics, Orbital plane, 010308 nuclear & particles physics, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Orbital eccentricity, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Orbital period, 01 natural sciences, Exoplanet, Radial velocity, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Orbital motion, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: In this paper, we report a refined determination of the orbital parameters and the detection of the Rossiter-McLaughlin effect of the recently discovered transiting exoplanet HD147506b (HAT-P-2b). The large orbital eccentricity at the short orbital period of this exoplanet is unexpected and is distinguishing from other known transiting exoplanets. We performed high-precision radial velocity spectroscopic observations of HD147506 (HAT-P-2) with the new spectrograph SOPHIE, mounted on the 1.93 m telescope at the Haute-Provence observatory (OHP). We obtained 63 new measurements, including 35 on May 14 and 20 on June 11, when the planet was transiting its parent star. The radial velocity (RV) anomaly observed illustrates that HAT-P-2b orbital motion is set in the same direction as its parent star spin. The sky-projected angle between the normal of the orbital plane and the stellar spin axis, \lambda = 0.2 +12.2 -12.5 deg, is consistent with zero. The planetary and stellar radii were re-determined, yielding R_p = 0.951 +0.039 -0.053 R_Jup, R_s = 1.416 +0.040 -0.062 R_Sun. The mass M_p = 8.62 +0.39 -0.55 M_Jup and radius of HAT-P-2b indicate a density of 12.5 +2.6 -3.6 g cm^{-3}, suggesting an object in between the known close-in planets with typical density of the order of 1 g cm^{-3}, and the very low-mass stars, with density greater than 50 g cm^{-3}., Comment: Submitted to A&A; V2: Replaced by accepted version
Published: 2007
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114. Elodie metallicity-biased search for transiting Hot Jupiters IV. Intermediate period planets orbiting the stars HD43691 and HD132406

Author: François Bouchy, Shay Zucker, X. Delfosse, D. Segransan, N. C. Santos, Frederic Pont, B. Loeillet, Stéphane Udry, G. Hebrard, F. Galland, C. Lovis, M. Mayor, Anne-Marie Lagrange, J. L. Beuzit, X. Bonfils, T. Forveille, D. Queloz, M. Desort, Alfred Vidal-Madjar, Jean-Pierre Sivan, C. Moutou, C. Perrier, R. F. Da Silva, Francesco Pepe, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), 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), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire 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), Centro de Astronomia e Astrofísica da Universidade de Lisboa (CAAUL), Universidade de Lisboa (ULISBOA), Université de Genève = University of Geneva (UNIGE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Universidade de Lisboa = University of Lisbon (ULISBOA)
Subjects: Period (periodic table), Metallicity, media_common.quotation_subject, FOS: Physical sciences, Minimum mass, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Planet, 0103 physical sciences, Hot Jupiter, techniques: radial velocities, Astrophysics::Solar and Stellar Astrophysics, Eccentricity (behavior), 010303 astronomy & astrophysics, Spectrograph, planetary systems, Astrophysics::Galaxy Astrophysics, media_common, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Stars, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, stars: individual: HD&thinsp
Abstract: We report here the discovery of two planet candidates as a result of our planet-search programme biased in favour of high-metallicity stars, using the ELODIE spectrograph at the Observatoire de Haute Provence. One of them has a minimum mass m_2\sin{i} = 2.5 M_Jup and is orbiting the metal-rich star HD43691 with period P = 40 days and eccentricity e = 0.14. The other planet has a minimum mass m_2\sin{i} = 5.6 M_Jup and orbits the slightly metal-rich star HD132406 with period P = 974 days and eccentricity e = 0.34. Both stars were followed up with additional observations using the new SOPHIE spectrograph that replaces the ELODIE instrument, allowing an improved orbital solution for the systems., 6 pages, 4 figures, to be published in A&A
Published: 2007
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115. Spectropolarimetric observations of the transiting planetary system of the K dwarf HD 189733

Author: Stéphane Udry, Jean-François Donati, A. Collier Cameron, Alfred Vidal-Madjar, R. Savalle, Evelyne Alecian, François Bouchy, C. Catala, G. A. J. Hussain, C. Moutou, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), 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), School of Physics and Astronomy, University of St Andrews, 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Department of Physics, Royal Military College of Canada, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de l'Université de Genève, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of St Andrews [Scotland], Laboratoire d'Astrophysique de Toulouse-Tarbes, École normale supérieure - Lyon (ENS Lyon)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: FOS: Physical sciences, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], symbols.namesake, Planet, 0103 physical sciences, Differential rotation, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Physics, Photosphere, Zeeman effect, 010308 nuclear & particles physics, Stellar rotation, Astrophysics (astro-ph), Giant planet, Astronomy and Astrophysics, Planetary system, Orbital period, 13. Climate action, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: With a Jupiter-mass planet orbiting at a distance of only 0.031 AU, the active K2 dwarf HD 189733 is a potential candidate in which to study the magnetospheric interactions of a cool star with its recently-discovered close-orbiting giant planet. We decided to explore the strength and topology of the large-scale magnetosphere of HD 189733, as a future benchmark for quantitative studies for models of the star/planet magnetic interactions. To this end, we used ESPaDOnS, the new generation spectropolarimeter at the Canada-France-Hawaii 3.6m telescope, to look for Zeeman circular polarisation signatures in the line profiles of HD 189733 in 2006 June and August. Zeeman signatures in the line profiles of HD 189733 are clearly detected in all spectra, demonstrating that a field is indeed present at the surface of the star. The Zeeman signatures are not modulated with the planet's orbital period but apparently vary with the stellar rotation cycle. The reconstructed large-scale magnetic field, whose strength reaches a few tens of G, is significantly more complex than that of the Sun; it involves in particular a significant toroidal component and contributions from magnetic multipoles of order up to 5. The CaII H & K lines clearly feature core emission, whose intensity is apparently varying mostly with rotation phase. Our data suggest that the photosphere and magnetic field of HD 189733 are sheared by a significant amount of differential rotation. Our initial study confirms that HD 189733 is an optimal target for investigating activity enhancements induced by closely orbiting planets. More data are needed, densely covering both the orbital and rotation cycles, to investigate whether and how much the planet contributes to the overall activity level of HD 189733., Accepted in Astronomy and Astrophysics, 12 pages
Published: 2007
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116. Interstellar abundances in the neutral and ionized gas of NGC 604

Author: J. Lequeux, Jean-Michel Desert, A. Lecavelier des Etangs, Vianney Lebouteiller, G. Hebrard, D. Kunth, Alessandra Aloisi, Alfred Vidal-Madjar, 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), 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), Departement de Radioastronomie Millimétrique (DEMIRM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Spiral galaxy, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010504 meteorology & atmospheric sciences, Absorption spectroscopy, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Plasma, Astrophysics, 01 natural sciences, Spectral line, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, Ionization, Phase (matter), 0103 physical sciences, Optical emission spectroscopy, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Line (formation)
Abstract: We present FUSE spectra of the giant HII region NGC604 in the spiral galaxy M33. Chemical abundances are derived from far-UV absorption lines and are compared to those derived from optical emission lines. We derived the column densities of HI, NI, OI, SiII, PII, ArI, and FeII, fitting the line profiles with either a single component or several components. Our net results, assuming a single component, show that N, O, Si, and Ar are apparently underabundant in the neutral phase by a factor of 10 or more with respect to the ionized phase, while Fe is the same. However, we discuss the possibility that the absorption lines are made of individual unresolved components, and find that only PII, ArI, and FeII lines should not be affected by the presence of hidden saturated components, while NI, OI, and SiII might be much more affected. If N, O, and Si are actually underabundant in the neutral gas of NGC604 with respect to the ionized gas, this would confirm earlier results obtained for the blue compact dwarfs. However, a deeper analysis focused on P, Ar, and Fe mitigates the above conclusion and indicates that the neutral gas and ionized gas could have similar abundances., Comment: Accepted for publication in A&A
Published: 2006
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117. Planetary transits: a first direct vision of extrasolar planets

Author: Alain Lecavelier des Etangs and Alfred Vidal-Madjar
Published: 2006
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118. Zeeman effect

Author: Alfred Vidal-Madjar
Published: 2006
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119. Lyman alpha

Author: Alfred Vidal-Madjar
Published: 2006
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120. Galactic Bulge Microlensing Optical Depth from EROS-2

Author: J. B. Marquette, L. Le Guillou, P. Bareyre, E. Maurice, C. Magneville, Y. R. Rahal, P. Tisserand, J. Rich, C. Hamadache, A. Milsztajn, J. N. Albert, Roger Ferlet, Bertrand Goldman, E. Lesquoy, David S. Graff, Johannes Andersen, Michel Spiro, Andrew Gould, Jean-Philippe Beaulieu, X. Charlot, C. Loup, J. Haissinski, Anaëlle Maury, Pascal Fouqué, J. F. Glicenstein, Ch. Coutures, Reza Ansari, O. Perdereau, L. Vigroux, C. Afonso, Marc Moniez, M. Gros, Nathalie Palanque-Delabrouille, S. Zylberajch, Alfred Vidal-Madjar, Éric Aubourg, J. de Kat, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), EROS, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Gravitational microlensing, 01 natural sciences, Einstein radius, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Bulge, 0103 physical sciences, Optical depth (astrophysics), Galaxy:stellar contents, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Galaxy:bar, Physics, Cosmology:gravitational lensing, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Light curve, Galaxy:structure, Stars, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics
Abstract: We present a new EROS-2 measurement of the microlensing optical depth toward the Galactic Bulge. Light curves of $5.6\times 10^{6}$ clump-giant stars distributed over $66 \deg^2$ of the Bulge were monitored during seven Bulge seasons. 120 events were found with apparent amplifications greater than 1.6 and Einstein radius crossing times in the range $5 {\rm d}, Comment: accepted A&A, minor revisions
Published: 2006
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121. Qualitative Physics on a Macroscopic Scale

Author: Alfred Vidal-Madjar
Subjects: Physics, Qualitative physics, Neutron star, Macroscopic scale, White dwarf, Gravitational interaction, Astrophysics, Statistical physics, Gravitational energy
Published: 2005
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122. FUSE observations of molecular hydrogen on the line of sight towards HD141569A

Author: P. D. Feldman, Theodore Simon, A. Lecavelier des Etangs, Jean-Claude Bouret, Aki Roberge, C. Martin-Zaidi, Alfred Vidal-Madjar, Magali Deleuil, Faure, Alexandre, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Mean kinetic temperature, Extinction (astronomy), Interstellar cloud, FOS: Physical sciences, Astrophysics, stars: pre-main sequence, 01 natural sciences, ISM: clouds, Spectral line, ISM: abundances, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Envelope (waves), Physics, stars: individual: HD 141569A, Line-of-sight, Astrophysics (astro-ph), Astronomy and Astrophysics, Radial velocity, Interstellar medium, Space and Planetary Science, stars: circumstellar matter
Abstract: We present an analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of HD141569A, a transitional object known to possess a circumstellar disk. We observe two components of gas at widely different temperatures along the line of sight. We detect cold H2, which is thermalized up to J=2 at a kinetic temperature of 51K. Such low temperatures are typical of the diffuse interstellar medium. Since the line of sight to HD141569A does not pass through its disk, it appears that we are observing the cold H2 in a low extinction envelope associated with the high Galactic latitude dark cloud complex L134N, which is in the same direction and at nearly the same distance as HD141569A. The column densities of the higher J-levels of H2 suggest the presence of warm gas along the line of sight. The excitation conditions do not seem to be consistent with what is generally observed in diffuse interstellar clouds. The observed radial velocity of the gas implies that the UV spectral lines we observe are likely interstellar in origin rather than circumstellar, although our absorption line study does not definitely rule out the possibility that the warm gas is close to the star. The discovery of such warm gas along the line of sight may provide evidence for turbulent phenomena in the dark cloud L134N., accepted for publication in A&A
Published: 2005
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123. New insights in the FUV into the activity of the Herbig Ae star <ASTROBJ>HD 163296</ASTROBJ>

Author: Roger Ferlet, Alfred Vidal-Madjar, Aki Roberge, C. Catala, J. C. Bouret, Paul D. Feldman, A. Lecavelier des Etangs, C. Martin, Magali Deleuil, 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), Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Terrestrial Magnetism, Carnegie Institution of Washington, and Department of Physics and Astronomy, Johns Hopkins University
Subjects: Physics, Photosphere, Spectral signature, Astronomy, Astronomy and Astrophysics, Astrophysics, Herbig Ae/Be star, Accretion (astrophysics), Spectral line, Space and Planetary Science, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Chromosphere, Line (formation)
Abstract: International audience; We present an analysis of the FUSE spectra of HD 163296, a young isolated Herbig Ae star. The spectra in the far UV spectral range are dominated by strong emission lines of C III and O VI, which exhibit broad and complex asymmetric profiles with wings extending over more than 1000 km s-1. The H I Ly alpha and the C III emission profiles show evidence for an outflow with a terminal velocity of 270 km s-1. We also identified several narrower emission lines due to fluorescent decays in Fe II. Using an HST/STIS archive spectrum, we checked that the H I Ly alpha line, which has a clear type III P Cygni emission profile, is broad enough to provide the photons required to photo-excite the Fe II upper levels. As previously explored for the well-known Herbig Ae star AB Aur, most of the spectral features including the fluorescent lines are consistent with the presence of a chromosphere above the photosphere. However, the over-ionized species cannot be produced in this region alone and we discuss two alternative mechanisms to explain such spectral signatures: magnetospheric accretion and a magnetically confined wind. Both interpretations involve a large-scale magnetic field whose detection is now a challenge for the new generation of spectropolarimeters such as ESPaDOnS.
Published: 2005
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124. The transmission spectrum of Earth-size transiting planets

Author: Alain Lecavelier des Etangs, Franck Selsis, Alfred Vidal-Madjar, Giovanna Tinetti, David Ehrenreich, 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), 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), NASA Astrobiology Institute (NAI), Centre de Recherche Astrophysique de Lyon (CRAL), 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), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: transits, Solar System, spectroscopy, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, Astrobiology, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Planet, extrasolar planets, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Near-infrared spectroscopy, Astrophysics (astro-ph), Astronomy and Astrophysics, Exoplanet, Stars, 13. Climate action, Space and Planetary Science, atmospheres, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics
Abstract: A variety of terrestrial planets with different physical parameters and exotic atmospheres might plausibly exist outside our Solar System, waiting to be detected by the next generation of space-exploration missions. Some of these planets might transit their parent star. We present here the first study of atmospheric signatures of transiting Earth-size exoplanets. We focus on a limited number of significant examples, for which we discuss the detectability of some of the possible molecules present in their atmospheres, such as water, carbon dioxide, ozone or molecular oxygen. To this purpose, we developed a model to simulate transmission spectra of Earth-size exoplanets from the ultraviolet to the near infrared. According to our calculations, the signatures of planetary atmospheres represent an absorption of a few parts-per-million (ppm) in the stellar flux. The atmospheres of a few Earth-like planets can be detected with a 30-40m telescope. The detection of the extensive atmospheres of tens of small satellites of giant exoplanets and hundreds of hypothetical ocean-planets can be achieved with 20-30m and 10-20m instruments, respectively, provided all these planets are frequent and they are efficiently surveyed. We also found that planets around K stars are favored, mainly because these stars are more numerous and they are smaller compared to G or F stars. While not addressed in this study, limitations might come from the stellar photometric micro-variability., Comment: Accepted in A&A (29/09/2005)
Published: 2005
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125. Velocity Dispersion of the High Rotational Levels of H2

Author: Roger Ferlet, V. Ziskin, Alfred Vidal-Madjar, Sylvestre Lacour, M. K. André, G. Hebrard, Cristina Oliveira, Department of Physics and Astronomy, Johns Hopkins University, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and AZimov Association
Subjects: Physics, Stars, Amplitude, Space and Planetary Science, Turbulence, Excited state, Velocity dispersion, Astronomy and Astrophysics, Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation, Line (formation), Magnetic field
Abstract: International audience; We present a study of the high rotational bands (J>=2) of H2 toward four early-type Galactic stars: HD 73882, HD 192639, HD 206267, and HD 207538. In each case, the velocity dispersion, characterized by the spectrum fitting parameter b, increases with the level of excitation, a phenomenon that has previously been detected by the Copernicus and IMAPS observatories. In particular, we show with 4 sigma confidence that for HD 192639 it is not possible to fit all J levels with a single b-value and that higher b-values are needed for the higher levels. The amplitude of the line broadening, which can be as high as 10 km s-1, makes explanations such as inhomogeneous spatial distribution unlikely. We investigate a mechanism in which the broadening is due to the molecules that are rotationally excited through the excess energy acquired after their formation on a grain (H2 formation pumping). We show that different dispersions would be a natural consequence of this mechanism. We note, however, that such a process would require a formation rate 10 times higher than what was inferred from other observations. In view of this result, and of the difficulty in accounting for the velocity dispersion as thermal broadening (T would be around 10,000 K), we conclude then that we are most certainly observing some highly turbulent warm layer associated with the cold diffuse cloud. Embedded in a magnetic field, it could be responsible for the high quantities of CH+ measured in the cold neutral medium.
Published: 2005
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126. FUSE observations of the $\ion{H}{I}$ interstellar gas of I Zw 18

Author: Roger Ferlet, A. Lecavelier des Etangs, D. Kunth, G. Hebrard, Jean-Michel Desert, Alfred Vidal-Madjar, Vianney Lebouteiller, G. Callejo, 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), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Argon, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010308 nuclear & particles physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], chemistry.chemical_element, Lower edge, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Oxygen, Nitrogen, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], chemistry, Space and Planetary Science, Ionization, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Dwarf galaxy
Abstract: We present the analysis of FUSE observations of the metal-deficient dwarf galaxy IZw18. We measured column densities of HI, NI, OI, ArI, SiII, and FeII. The OI/HI ratio (log(OI/HI)=-4.7^{+0.8}_{-0.6}) is consistent with the O/H ratio observed in the HII regions (all uncertainties are 2-sigma). If the oxygen is depleted in the HI region compared to the HII regions, the depletion is at most 0.5dex. This is also consistent with the log(O/H) ratios ~-5 measured with FUSE in the HI regions of other blue compact dwarf galaxies. With log(NI/OI)=-2.4^{+0.6}_{-0.8}, the measured NI/OI ratio is lower than expected for primary nitrogen. The determination of the NII column density is needed to discriminate between a large ionization of NI or a possible nitrogen deficiency. The neutral argon is also apparently underabundant, indicating that ionization into ArII is likely important. The column densities of the other alpha-chain elements SiII and ArI favor the lower edge of the permitted range of OI column density, log(N(OI))~16.3.
Published: 2004
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127. Detection of oxygen and carbon in the hydrodynamically escaping atmosphere of the extrasolar planet HD209458b

Author: A. Lecavelier des Etangs, G. Hebrard, Christopher D. Parkinson, Roger Ferlet, G. E. Ballester, J. C. McConnell, Jean-Michel Desert, M. Mayor, David Ehrenreich, and Alfred Vidal-Madjar
Subjects: Physics, Astrophysics (astro-ph), chemistry.chemical_element, FOS: Physical sciences, Astronomy and Astrophysics, Lyman-alpha line, Astrophysics, Oxygen, Exoplanet, Atmosphere, chemistry, Space and Planetary Science, Planet, Roche lobe, Absorption (electromagnetic radiation), Hydrodynamic escape
Abstract: Four transits of the planet orbiting the star HD209458 were observed with the STIS spectrograph on board HST. The wavelength domain (1180-1710A) includes HI as well as CI, CII, CIV, NV, OI, SI, SiII, SiIII and SiIV lines. During the transits, absorptions are detected in HI, OI and CII (5+/-2%, 13+/-4.5% and 7.5+/-3.5%, respectively). No absorptions are detected for other lines. The 5% mean absorption over the whole HI Lyman alpha line is consistent with the previous detection at higher resolution (Vidal-Madjar et al. 2003). The absorption depths in OI and CII show that oxygen and carbon are present in the extended upper atmosphere of HD209458b. These species must be carried out up to the Roche lobe and beyond, most likely in a state of hydrodynamic escape., Comment: 6 pages, 4 figures, 1 table, submitted to ApJ Letters, revised version with slightly revisited absorption depth estimates
Published: 2004
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128. Evidence for wind and accretion in the Herbig Be star <ASTROBJ>HD 100546</ASTROBJ> from FUSE observations

Author: Roger Ferlet, Aki Roberge, Alfred Vidal-Madjar, Paul D. Feldman, Jean-Claude Bouret, C. Martin, Magali Deleuil, A. Lecavelier des Etangs, 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), Aix Marseille Université (AMU), Institut d'Astrophysique de Paris (IAP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Spectral signature, Absorption spectroscopy, Be star, Astronomy, Magnetosphere, stars: emission-line, Astronomy and Astrophysics, Be, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, stars: pre-main sequence, Herbig Ae/Be star, Spectral line, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Solar and Stellar Astrophysics, stars: individual: HD 100546, Astrophysics::Earth and Planetary Astrophysics, Emission spectrum, stars: circumstellar matter, Basso continuo, Astrophysics::Galaxy Astrophysics
Abstract: International audience; We present the first far-UV spectra of the Herbig Be star HD 100546, observed by the Far Ultraviolet Spectroscopic Explorer (FUSE) as part of the Circumstellar Disks team program. We identified and analyzed numerous narrow absorption lines of circumstellar origin. Intense, broad and fairly asymmetric emission lines of C II, C III, O VI and S II were also detected, spanning temperatures up to 3× 105 K. Comparison of the spectra recorded two years apart reveals strong spectral variations, not only in the emission lines but also in the circumstellar lines of N I, N II, O I, Ar I and Fe II. The varying absorption lines of N I and O I exhibit the largest velocity width, from -200 to +320 km s-1, relative to the star's rest-frame. Variations on a timescale of an hour occurred only in the N I resonance triplet and O I (1D) lines. The spectroscopic variability highlighted by these two observations and the line profile analysis reveal signatures of both outflow and infall processes, which appear to be related in this system. We suggest that these spectral signatures originate in a stellar magnetosphere, which likely interacts with the innermost part of the star's circumstellar disk. This interpretation can account for the main features observed in the spectrum of HD 100546: variable emission and absorption lines as well as suspected continuum variation.
Published: 2004
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129. Tiny-scale molecular structures in the Magellanic Clouds. I. FUSE, HST and VLT observations

Author: E. Roueff, F. Lepetit, Alfred Vidal-Madjar, Jean-Michel Desert, Kuassivi-Andre, Sylvestre Lacour, Paule Sonnentrucker, T. Civeit, Roger Ferlet, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), 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), Onsala Space Observatory, Chalmers University of Technology (OSO), Johns Hopkins University (JHU), 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, Pôle Astronomie du LESIA, and 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris
Subjects: Physics, Stars, Deuterium, Space and Planetary Science, Photodissociation, Flux, Astronomy and Astrophysics, Scale (descriptive set theory), Small Magellanic Cloud, Astrophysics, Large Magellanic Cloud, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The objective of this series of two papers is to investigate small-scale molecular structures in the Magellanic Clouds (hereafter MCs). We report on the FUSE detections of the HD and CO molecules on the lines of sight towards three Large Magellanic stars: Sk -67D05, Sk -68D135, and Sk -69D246. HD is also detected for the first time on the lines of sight towards two Small Magellanic Cloud stars: AV 95 and Sk 159. While the HD and CO abundances are expected to be lower in the Large Magellanic Cloud where molecular fractions are a third of the Galactic value and where the photodissociation flux is up to thousands of times as large, we report an average HD/H2 ratio of 1.4±0.5 ppm and a CO/H2 ratio ranging from 0.8 to 2.7 ppm similar to the Galactic values. We tentatively identify a deuterium reservoir (hereafter D-reservoir) towards the Small Magellanic Cloud, along the light path to AV 95. We derive a D/H ratio ranging from 1.× 10-6 to 1.1× 10-5. Combining FUSE and HST/STIS data we also analyzed the H2, Cl I, Cl II, Fe II, S II, C I, C I*, and C I** content, when available. High resolution VLT observations of Na I, Ca II, and Ca I were obtained in support of the lower resolution FUSE and STIS data for three targets in order to unravel the sightline velocity structures. These observations form the only such set of detections in the Magellanic Clouds to date and allow us to investigate in detail some of the physical properties of the intervening molecular gas. Our detection of the HD and CO molecules in the Magellanic Clouds is an argument for the existence of dense (nH > 100 cm-3) components. Furthermore, we demonstrate that these components are probably extremely small molecular clumps (possibly as small as 10-2 pc) or filaments similar to the tiny-scale atomic structures (TSAS) recently observed in the halo of our Galaxy by Richter et al. (\cite{Richter2003}). For these five sightlines, we also detected molecular hydrogen originating in the Galactic disk. From these observations we conclude that tiny-scale molecular filamentary structures are present in the disk of the Galaxy as well.
Published: 2004
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130. Type Ia supernova rate at a redshift of ~ 0.1

Author: A. Milsztajn, F. Derue, G. Garavini, A. Kim, Tomas Dahlen, C. Magneville, Ariel Goobar, Gastón Folatelli, Alexis Amadon, P. Tisserand, C. Loup, E. Maurice, Nicholas A. Walton, C. Afonso, Y. R. Rahal, Guillermo A. Blanc, S. Nobili, D. Hardin, Heidi Jo Newberg, J. F. Glicenstein, L. Prevot, Johannes Andersen, Michel Spiro, Ch. Coutures, Nathalie Palanque-Delabrouille, Bertrand Goldman, C. Hamadache, Jean-Philippe Beaulieu, Anaëlle Maury, S. Zylberajch, P. Bareyre, Thierry Lasserre, L. LeGuillou, Roger Ferlet, O. Perdereau, J. N. Albert, Pascal Fouqué, J. B. Marquette, Xiaohui Fan, Alex Conley, C. Alard, R. Ansari, J. deKat, Alfred Vidal-Madjar, David S. Graff, J. Rich, M. Mouchet, Christophe Balland, Éric Aubourg, Nicolas Regnault, I. M. Hook, L. Vigroux, Pilar Ruiz-Lapuente, X. Charlot, M. Gros, Andrew Gould, Greg Aldering, Stephen M. Kent, M. Moniez, J. Haissinski, E. Lesquoy, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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 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), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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), Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), EROS, Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Services communs OMP - UMS 831 (UMS 831), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), 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), 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), and 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)
Subjects: Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Supernova, 010308 nuclear & particles physics, Monte Carlo method, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Type (model theory), 01 natural sciences, Redshift, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, Rate measurement, 0103 physical sciences, 010303 astronomy & astrophysics
Abstract: We present the type Ia rate measurement based on two EROS supernova search campaigns (in 1999 and 2000). Sixteen supernovae identified as type Ia were discovered. The measurement of the detection efficiency, using a Monte Carlo simulation, provides the type Ia supernova explosion rate at a redshift ~ 0.13. The result is $0.125^{+0.044+0.028}_{-0.034-0.028} h_{70}^2$ SNu where 1 SNu = 1 SN / $10^{10} L_{sun}^B$ / century. This value is compatible with the previous EROS measurement (Hardin et al. 2000), done with a much smaller sample, at a similar redshift. Comparison with other values at different redshifts suggests an evolution of the type Ia supernova rate., Comment: Accepted for publication in Astronomy & Astrophysics (15 pages, 16 figures)
Published: 2004
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131. Oxygen Gas Phase Abundance Revisited

Author: Roger Ferlet, A. Lecavelier des Etangs, M. K. André, Cristina Oliveira, Sylvestre Lacour, H. W. Moos, Alfred Vidal-Madjar, Jean-Michel Desert, J. C. Howk, Guillaume Hébrard, 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), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and arXiv, Import
Subjects: Physics, 010504 meteorology & atmospheric sciences, Hydrogen, Abundance (chemistry), Star (game theory), Astrophysics (astro-ph), FOS: Physical sciences, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Oxygen, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Stars, chemistry, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 13. Climate action, Space and Planetary Science, Phase (matter), 0103 physical sciences, Content (measure theory), Oxygen gas, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We present new measurements of the interstellar gas-phase oxygen abundance along the sight lines towards 19 early-type galactic stars at an average distance of 2.6 kpc. We derive O {\small I} column densities from {\it HST}/STIS observations of the weak 1355 \AA intersystem transition. We derive total hydrogen column densities [N(H {\small I})+2N(H$_2$)] using {\it HST}/STIS observations of \lya and {\it FUSE} observations of molecular hydrogen. The molecular hydrogen content of these sight lines ranges from f(H$_2$) = 2N(H$_2$)/[N(H {\small I})+2N(H$_2$)] = 0.03 to 0.47. The average $$ of 6.3$\times10^{21}$ cm$^{-2}$ mag$^{-1}$ with a standard deviation of 15% is consistent with previous surveys. The mean oxygen abundance along these sight lines, which probe a wide range of galactic environments in the distant ISM, is 10$^6$ \oh = $408 \pm 13$ (1 $\sigma$ in the mean). %$({\rm O/H})_{gas} = 408 \pm 14$(1 $\sigma$). We see no evidence for decreasing gas-phase oxygen abundance with increasing molecular hydrogen fraction and the relative constancy of \oh suggests that the component of dust containing the oxygen is not readily destroyed. We estimate that, if 60% of the dust grains are resilient against destruction by shocks, the distant interstellar total oxygen abundance can be reconciliated with the solar value derived from the most recent measurements %by Holweger and by Allende Prieto, Lambert & Asplund: of 10$^6$ \oh$_\odot$ = 517 $\pm$ 58 (1 $\sigma$). We note that the smaller oxygen abundances derived for the interstellar gas within 500 pc %by Meyer, Cardelli & Jura or from nearby B star surveys are consistent with a local elemental deficit., Comment: 9 figures, 37 pages
Published: 2003

132. Limits on Galactic Dark Matter with 5 Years of EROS SMC Data

Author: C. Hamadache, L. Le Guillou, P. Fouque, Alfred Vidal-Madjar, Y. R. Rahal, L. Prevot, Andrew Gould, F. Couchot, R. Ansari, J. F. Glicenstein, Ch. Coutures, E. Maurice, P. Tisserand, Christophe Magneville, Thierry Lasserre, S. Zylberajch, David S. Graff, Jean-Philippe Beaulieu, É. Lesquoy, X. Charlot, Anaëlle Maury, J. Rich, C. Loup, C. Afonso, J. N. Albert, Roger Ferlet, Bertrand Goldman, M. Moniez, P. Bareyre, G. Blanc, J. Haissinski, A. Milsztajn, M. Gros, Éric Aubourg, J. B. Marquette, Nathalie Palanque-Delabrouille, O. Perdereau, J. de Kat, L. Vigroux, Johannes Andersen, Michel Spiro, Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), 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), 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), EROS, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Physics, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Dark matter, Population, Astrophysics (astro-ph), Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Gravitational microlensing, 01 natural sciences, Cosmology, Galactic halo, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Gravitational lens, Space and Planetary Science, 0103 physical sciences, Halo, Small Magellanic Cloud, education, 010303 astronomy & astrophysics
Abstract: Five years of EROS data towards the Small Magellanic Cloud have been searched for gravitational microlensing events, using a new, more accurate method to assess the impact of stellar blending on the efficiency. Four long-duration candidates have been found which, if they are microlensing events, hint at a non-halo population of lenses. Combined with results from other EROS observation programs, this analysis yields strong limits on the amount of Galactic dark matter made of compact objects. Less than 25% of a standard halo can be composed of objects with a mass between 2 10^-7 Msol and 1 Msol at the 95% C.L., 6 pages, 3 figures. Accepted for publication in A&A
Published: 2003
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133. Lyman Gamma Satellites Due to H-H+ Collisions: Application to FUSE Observations of Hot White Dwarfs

Author: Guillaume Hébrard, John F. Kielkopf, Ivan Hubeny, Roger Ferlet, Nicole F. Allard, Alfred Vidal-Madjar, Jean-Michel Desert, S. Bourdreux, and J. M. Peek
Subjects: Physics, Feature (computer vision), Fuse (electrical), Brown dwarf, Astronomy, White dwarf, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Blue dwarf
Abstract: New theoretical calculations of Lyman 7 profiles perturbed by protons allow us to identificate a large feature near 995 A in FUSE observations of hot white dwarfs. This feature is due to quasi-molecular Lyman γ satellites due to H-H+ collisions near 991 and 996 A.
Published: 2003
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134. An extended upper atmosphere around the extrasolar planet HD209458b

Author: Alfred Vidal-Madjar, Roger Ferlet, Gilda E. Ballester, A. Lecavelier des Etangs, Jean-Michel Desert, M. Mayor, and Guillaume Hébrard
Subjects: Physics, Multidisciplinary, Gas giant, Atmosphere, Astronomy, Planets, Lyman-alpha line, Astrophysics, Exoplanet, Radial velocity, Planet, Hot Jupiter, Roche limit, Astrophysics::Earth and Planetary Astrophysics, Gases, Hydrogen
Abstract: The planet in the system HD209458 is the first one for which repeated transits across the stellar disk have been observed1,2. Together with radial velocity measurements3, this has led to a determination of the planet's radius and mass, confirming it to be a gas giant. But despite numerous searches for an atmospheric signature4,5,6, only the dense lower atmosphere of HD209458b has been observed, through the detection of neutral sodium absorption7. Here we report the detection of atomic hydrogen absorption in the stellar Lyman α line during three transits of HD209458b. An absorption of 15 ± 4% (1σ) is observed. Comparison with models shows that this absorption should take place beyond the Roche limit and therefore can be understood in terms of escaping hydrogen atoms.
Published: 2002

135. ARAGO: a robotic observatrory for the variable sky

Author: Gilles Buchholtz, Marc Ferrari, Carole Thiebaut, Alain Klotz, François Colas, N. Dolez, Pierre Jean, Jean Schneider, Driss Kouach, Roger Ferlet, Lionel Provost, Alain Lecavelier des Etangs, Richard Verchere, J. Eysseric, Sylvie Roques, Magali Deleuil, Jean-Pierre Meunier, Michel Dennefeld, Jean-Luc Atteia, Jean-Babtiste Marquette, Agnes Acker, Robert Mochkovitch, Caroline Soubiran, A. Marcowith, Gérard Vauclair, Roger Pinna, Michel Boer, L. Parès, Reynald Pain, Gerard R. Lemaitre, Alfred Vidal-Madjar, Henri Pinna, Jean-Michel Desert, Jean-Pierre Sivan, CNRS/ULP, UMR 7175-LC1, Ecole Supérieure de Biotechnologie de Strasbourg, Bld. Sébastien Brandt BP. 10413, F-67412 Illkirch, France., Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), 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), Institut national des sciences de l'Univers (INSU - CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de Marseille Provence (OAMP), Université de Provence - Aix-Marseille 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Tyson, J. Anthony, Wolff, and Sidney
Subjects: Physics, COSMIC cancer database, media_common.quotation_subject, Astronomy, Astrophysics, Gravitational microlensing, Exoplanet, law.invention, Telescope, Observatory, Sky, Planet, law, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], media_common, Space debris
Abstract: International audience; We present the Advanced Robotic Agile Observatory (ARAGO), a project for a large variability survey of the sky, in the range 10-8Hz (year) to 1Hz. Among its scientific objectives are the detection of cosmic gamma-ray bursts, both on alert and serendipitously, orphan afterglows, extrasolar planets, AGNs, quasar microlensing, variable and flare stars, trans-neptunian asteroids, Earth-grazers, orbital debris, etc. A large Education and Public Outreach program will be an important part of the project. The telescope itself will be made of Silicon Carbide, allowing, among other advantages, a very light weight and agile capabilities. ARAGO will be fully autonomous, i.e. there will be no human intervention from the request to the data processing and result dissemination, nor to assist night or day operations. ARAGO will start routine observation by mid-2005.
Published: 2002
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136. Hydrogen column density evaluations toward Capella: consequences on the interstellar deuterium abundance

Author: Roger Ferlet and Alfred Vidal-Madjar
Subjects: Systematic error, Physics, Line-of-sight, Hydrogen, Astrophysics (astro-ph), chemistry.chemical_element, Sigma, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Galaxy, Interstellar medium, chemistry, Deuterium, Space and Planetary Science, Abundance (ecology)
Abstract: The deuterium abundance evaluation in the direction of Capella has for a long time been used as a reference for the local interstellar medium (ISM) within our Galaxy. We show here that broad and weak HI components could be present on the Capella line of sight, leading to a large new additional systematic uncertainty on the N(HI) evaluation. The D/H ratio toward Capella is found to be equal to 1.67 (+/-0.3)x10^-5 with almost identical chi^2 for all the fits (this range includes only the systematic error; the 2 sigma statistical one is almost negligible in comparison). It is concluded that D/H evaluations over HI column densities below 10^19 cm^-2 (even perhaps below 10^20 cm^-2 if demonstrated by additional observations) may present larger uncertainties than previously anticipated. It is mentionned that the D/O ratio might be a better tracer for DI variations in the ISM as recently measured by the Far Ultraviolet Spectroscopic Explorer (FUSE)., Accepted for publication in the Astrophysical Journal Letters
Published: 2002

137. FUSE observations towards the pole-on Be star HR 5223

Author: Anne-Marie Hubert, Jean-Michel Desert, Juan Zorec, Alfred Vidal-Madjar, Y. Frémat, René D. Rohrmann, R. Ferlet, and Lydia Sonia Cidale
Subjects: Ciencias Astronómicas, Stars: emission-line, Be, Rotation, Be star, Ciencias Físicas, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), fundamental parameters [Stars], ISM: abundances, Spectral line, Gravitation, purl.org/becyt/ford/1 [https], Astrophysics::Solar and Stellar Astrophysics, HD 120991 (estrella), Stars: distances, Stars: individual: HR 5223, Stars: fundamental parameters, Astrophysics::Galaxy Astrophysics, Line (formation), abundances [ISM], Physics, Photosphere, individual: HR 5223 [Stars], Stars: rotation, Astronomy, Astronomy and Astrophysics, Circumstellar envelope, purl.org/becyt/ford/1.3 [https], distances [Stars], Stars, Astronomía, rotation [Stars], Interstellar medium, Emission line, emission-line, Be [Stars], Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, CIENCIAS NATURALES Y EXACTAS
Abstract: New spectra have been obtained for the pole-on Be star HR 5223 (HD 120991) using the Far Ultraviolet Satellite Explorer (FUSE). We give a complete description of the far-UV spectral range (920 to 1180 Å). The spectra are affected by strong blends with interstellar lines and molecular bands that also significantly lower the energy distribution of the star. We produce a synthetic spectrum of the interstellar medium (ISM) to determine the column densities of several elements (H2, H I, N I, O I ...) seen towards HR 5223 and to disentangle the components due to the ISM, the photosphere and/or to the circumstellar envelope. The line identification list is available at the CDS. Using the obtained column densities, we determine the reddening of the star due to the ISM only and locate the star relative to the nearby IS clouds. The fit of the dereddened UV flux distribution with models that account for the gravitational darkening due to the stellar fast rotation allowed us to estimate the stellar fundamental parameters (Teff = 22 000 K; log g = 3.7) and its distance (d = 834 ± 20 pc). The distance obtained, which has to be considered as the most accurate available at the moment, is in agreement with the characteristics of the ISM matter distribution that affects the observed spectrum of the star and with the detecting limits of the HIPPARCOS satellite., Facultad de Ciencias Astronómicas y Geofísicas
Published: 2002

138. A chromospheric scenario for the activity of beta Pictoris, as revealed by FUSE

Author: Alfred Vidal-Madjar, A. Lecavelier des Etangs, A. Roberge, Magali Deleuil, Thierry Lanz, Jean-Claude Bouret, 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), Aix Marseille Université (AMU), Institut d'Astrophysique de Paris (IAP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Photosphere, stars: chromospheres, Astronomy, Astronomy and Astrophysics, line: profiles, Astrophysics, outflows, Stars, T Tauri star, Space and Planetary Science, [SDU]Sciences of the Universe [physics], stars: winds, stars: atmospheres, stars: activity, Radiative transfer, Beta Pictoris, Emission spectrum, Line (formation), Exocomet
Abstract: International audience; We investigate a chromospheric scenario to explain the characteristics of the far-UV emission lines of beta Pictoris, revealed by FUSE spectra of this famous circumstellar disk system. The model assumes a thin region heated up to a few 105 K located close to the stellar photosphere. The resonance lines of C III at 977 Å and O VI at 1032-1037 Å, seen in emission, are produced in this chromosphere-transition region complex. Using complementary data in the mid and near UV (specifically, a resonance doublet of C IV at 1548-1550 Å and Mg II h & k), we show that the whole dataset is remarquably well reproduced by the model. In addition, we investigate the properties of the C III* multiplet at 1176 Å and conclude that this line likely forms in a weak warm wind, originating from the prominent circumstellar disk of beta Pictoris. Finally, radiative losses have been calculated and have provided estimates of the amount of non radiative energy dissipated in the external atmosphere of beta Pictoris, which is a measure of the star's activity level. Such behavior for an A5 V star presents a challenge for both evolution and activity models since the former predict that main-sequence A stars should not be active, while the latter are unable to quantitatively account for the characteristics of the chromospheric heating of beta Pictoris.
Published: 2002
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139. A Far Ultraviolet Spectroscopic Explorer Survey of Interstellar Molecular Hydrogen in Translucent Clouds

Author: Edward B. Jenkins, J. Michael Shull, Paule Sonnentrucker, Blair D. Savage, Cecile Gry, Scott D. Friedman, Roger Ferlet, Donald C. Morton, Jason Tumlinson, Brian L. Rachford, Alfred Vidal-Madjar, Theodore P. Snow, Donald G. York, William P. Blair, Daniel E. Welty, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Range (particle radiation), Ultraviolet: ISM, Line-of-sight, Hydrogen, Mean kinetic temperature, Extinction (astronomy), Hydrogen molecule, ISM: Clouds, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, Kinetic energy, chemistry, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Molecule, ISM: Molecules, ISM: Abundances, ISM: Lines and Bands
Abstract: International audience; We report the first ensemble results from the Far Ultraviolet Spectroscopic Explorer survey of molecular hydrogen in lines of sight with AV>~1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column densities for J=0 and J=1, which contain >~99% of the total H2. From these column densities and ancillary data we have derived the total H2 column densities, hydrogen molecular fractions, and kinetic temperatures for 23 lines of sight. This is the first significant sample of molecular hydrogen column densities of ~1021 cm-2, measured through UV absorption bands. We have also compiled a set of extinction data for these lines of sight, which sample a wide range of environments. We have searched for correlations of our H2-related quantities with previously published column densities of other molecules and extinction parameters. We find strong correlations between H2 and molecules such as CH, CN, and CO, in general agreement with predictions of chemical models. We also find the expected correlations between hydrogen molecular fraction and various density indicators such as kinetic temperature, CN abundance, the steepness of the far-UV extinction rise, and the width of the 2175 Å bump. Despite the relatively large molecular fractions, we do not see the values greater than 0.8 expected in translucent clouds. With the exception of a few lines of sight, we see little evidence for the presence of individual translucent clouds in our sample. We conclude that most of the lines of sight are actually composed of two or more diffuse clouds similar to those found toward targets like ζ Oph. We suggest a modification in terminology to distinguish between a ``translucent line of sight'' and a ``translucent cloud.''
Published: 2002
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140. The Mg i line: a new probe of the atmospheres of evaporating exoplanets

Author: Alfred Vidal-Madjar, Vincent Bourrier, and A. Lecavelier des Etangs
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Atmospheric escape, Exoplanetology, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Exoplanet, Atmosphere, Stars, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Transit (astronomy), 010306 general physics, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, Line (formation)
Abstract: Transit observations of HD209458b in the UV revealed signatures of neutral magnesium escaping the planet's upper atmosphere. The absorption detected in the MgI line provides unprecedented information on the physical conditions at the altitude where the atmospheric blow-off takes place. Here we use a 3D model of atmospheric escape to estimate the transit absorption signatures in the MgI line of their host stars. The detectability of these signatures depends on the brightness of the star and the escape rate of neutral magnesium. We identify a sample of potentially evaporating exoplanets that covers a wide range of stellar and planetary properties, and whose extended exospheres might be detected through MgI line observations with current UV facilities, allowing further steps in comparative exoplanetology., Comment: 4 pages, 2 figures
Published: 2014
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141. Modeling magnesium escape from HD 209458b atmosphere

Author: A. Lecavelier des Etangs, Vincent Bourrier, and Alfred Vidal-Madjar
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Electron density, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, 7. Clean energy, 01 natural sciences, Spectral line, Atmosphere, Radiation pressure, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract: Transit observations in the MgI line of HD209458b revealed signatures of neutral magnesium escaping the upper atmosphere of the planet, while no atmospheric absorption was found in the MgII doublet. Here we present a 3D particle model of the dynamics of neutral and ionized magnesium populations, coupled with an analytical modeling of the atmosphere below the exobase. Theoretical MgI absorption line profiles are directly compared with the absorption observed in the blue wing of the line during the planet transit. Observations are well-fitted with an escape rate of neutral magnesium in the range 2x10^7-3.4x10^7 g/s, an exobase close to the Roche lobe (Rexo in the range 2.1-4.3 Rp, where Rp is the planet radius) and a planetary wind velocity at the exobase vpl=25km/s. The observed velocities of the planet-escaping magnesium up to -60km/s are well explained by radiation pressure acceleration, provided that UV-photoionization is compensated for by electron recombination up to about 13Rp. If the exobase properties are constrained to values given by theoretical models of the deeper atmosphere (Rexo=2Rp and vpl=10km/s), the best fit to the observations is found at a similar electron density and escape rate within 2 sigma. In all cases, the mean temperature of the atmosphere below the exobase must be higher than about 6100 K. Simulations predict a redward expansion of the absorption profile from the beginning to the end of the transit. The spatial and spectral structure of the extended atmosphere is the result of complex interactions between radiation pressure, planetary gravity, and self-shielding, and can be probed through the analysis of transit absorption profiles in the MgI line., Comment: 16 pages, 24 figures
Published: 2014
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142. The Earth as an extrasolar transiting planet

Author: Roger Ferlet, Luc Arnold, David Ehrenreich, Xavier Dumusque, Richard Querel, C. Moutou, Christian Nitschelm, D. Crooker, C. Lovis, Jérôme Berthier, Alfred Vidal-Madjar, and Pascal Hedelt
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, 7. Clean energy, Earth radius, Exoplanet, Atmosphere, Atmosphere of Earth, 13. Climate action, Space and Planetary Science, Planet, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Transit (astronomy), Spectral resolution, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: The atmospheric composition of transiting exoplanets can be characterized during transit by spectroscopy. For the transit of an Earth twin, models predict that biogenic $O_2$ and $O_3$ should be detectable, as well as water vapour, a molecule linked to habitability as we know it on Earth. The aim is to measure the Earth radius versus wavelength $\lambda$ - or the atmosphere thickness $h(\lambda)$ - at the highest spectral resolution available to fully characterize the signature of Earth seen as a transiting exoplanet. We present observations of the Moon eclipse of 21-12-2010. Seen from the Moon, the Earth eclipses the Sun and opens access to the Earth atmosphere transmission spectrum. We used HARPS and UVES spectrographs to take penumbra and umbra high-resolution spectra from 3100 to 10400 Ang. A change of the quantity of water vapour above the telescope compromised the quality of the UVES data. We corrected for this effect in the data processing. We analyzed the data by 3 different methods. The 1st method is based on the analysis of pairs of penumbra spectra. The 2nd makes use of a single penumbra spectrum, and the 3rd of all penumbra and umbra spectra. Profiles $h(\lambda)$ are obtained with the three methods for both instruments. The 1st method gives the best result, in agreement with a model. The second method seems to be more sensitive to the Doppler shift of solar spectral lines with respect to the telluric lines. The 3rd method makes use of umbra spectra which bias the result, but it can be corrected for this a posteriori from results with the first method. The 3 methods clearly show the spectral signature of the Rayleigh scattering in the Earth atmosphere and the bands of H$_2$O, O$_2$, and O$_3$. Sodium is detected. Assuming no atmospheric perturbations, we show that the E-ELT is theoretically able to detect the $O_2$ A-band in 8~h of integration for an Earth twin at 10pc., Comment: Final version accepted for publication in A&A - 21 pages, 27 figures. Abstract above slightly shortened wrt the original. The ArXiv version has low resolution figures, but a version with full resolution figures is available here: http://www.obs-hp.fr/~larnold/publi_to_download/eclipse2010_AA_v5_final.pdf
Published: 2014
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143. Exocomets in the circumstellar gas disk of HD 172555

Author: Jean-Charles Augereau, Flavien Kiefer, Anne-Marie Lagrange, Hervé Beust, Alain Lecavelier des Etangs, and Alfred Vidal-Madjar
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Debris disk, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Star (graph theory), 01 natural sciences, Spectral line, Radial velocity, Space and Planetary Science, 0103 physical sciences, Ultrafast laser spectroscopy, Angstrom, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract: The source HD172555 is a young A7V star surrounded by a debris disk with a gaseous component. Here, we present the detection of variable absorption features detected simultaneously in the Ca II K and H doublet lines (at 3,933 and 3,968 Angstrom). We identified the presence of these absorption signatures at four different epochs in the 129 HARPS high-resolution spectra gathered between 2004 and 2011. These transient absorption features are most likely due to Falling Evaporating Bodies (FEBs, or exocomets) that produce absorbing gas observed transiting in front of the central star. We also detect a stable Ca II absorption component at the star's radial velocity. With no corresponding detection in the Na I line, the resulting very low upper limit for the NaI/CaII ratio suggests that this absorption is due to circumstellar gas., Comment: Accepted for publication in Astronomy&Astrophysics Letters
Published: 2014
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144. Blue irregular variable stars in the Small Magellanic Cloud from EROS2 : Herbig Ae/Be or classical Be stars ?

Author: Alfred Vidal-Madjar, F. Derue, Roger Ferlet, Marc Moniez, Bertrand Goldman, F. Bauer, S. Totor, C. Afonso, Jean-Christophe Hamilton, L. Prevot, J. Rich, C. Loup, David S. Graff, S. Zylberajch, W. J. de Wit, E. Maurice, Pascal Fouqué, J. F. Glicenstein, Ch. Coutures, Reza Ansari, F. Couchot, O. Perdereau, J. N. Albert, G. Blanc, Éric Aubourg, J. B. Marquette, J. P. Beaulieu, H. J. G. L. M. Lamers, J. Haissinski, Christophe Magneville, B. Mansoux, J. de Kat, Nathalie Palanque-Delabrouille, É. Lesquoy, N. Regnault, L. Vigroux, P. Bareyre, X. Charlot, M. Gros, P. Leisy, T. Lasserre, A. Milsztajn, Johannes Andersen, Michel Spiro, C. Alard, D. Hardin, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), EROS, Lantz, Simone, and Fouqué, Pascal
Subjects: Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Gravitational microlensing, 01 natural sciences, Accretion (astrophysics), Luminosity, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Stars, Gravitational lens, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, 0103 physical sciences, Small Magellanic Cloud, Emission spectrum, Variable star, 010303 astronomy & astrophysics
Abstract: Using data from the EROS2 microlensing survey, we report the discovery of two blue objects with irregular photometric behaviour of $\Delta V \sim 0.1$-0.4 mag on time scales of 20 to 200 days. They show a bluer when fainter behaviour. Subsequent spectra taken with the ESO 3.6m telescope show spectral type B4eIII and B2eIV-V with strong $H \alpha$ emission. These objects resemble the Herbig AeBe but also classical Be stars. At this stage, it is not possible to distinguish unambiguously between pre-main sequence and classical Be nature. If we favour the pre-main sequence interpretation, they are more luminous than the luminosity upper limit for Galactic HAeBe stars. The same was found for the HAeBe candidates in the LMC. This might be due to a shorter accretion time scale ($\tau = M_*/\dot{M}$), or the smaller dust content during the pre-main sequence evolution of SMC and LMC stars., Comment: : 9 pages, LaTeX, 7 figures. Accepted for publications in AA
Published: 2001

145. Deficiency of molecular hydrogen in the disk of beta Pictoris

Author: Alfred Vidal-Madjar, A. Roberge, Guillaume Hébrard, Jean-Michel Desert, Jean-Claude Bouret, Roger Ferlet, Martin Lemoine, Paul D. Feldman, Scott D. Friedman, William P. Blair, H. W. Moos, M. Andre, M. Deleuil, and A. Lecavelier des Etangs
Subjects: Planetesimal, Debris disk, Carbon Monoxide, Multidisciplinary, Extraterrestrial Environment, Chemistry, Astronomy, Astronomical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Planetary system, Stars, Planet, Astrophysics::Solar and Stellar Astrophysics, Beta Pictoris, Spectrophotometry, Ultraviolet, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Main sequence, Exocomet, Hydrogen
Abstract: Molecular hydrogen (H2) is by far the most abundant material from which stars, protoplanetary disks and giant planets form, but it is difficult to detect directly. Infrared emission lines from H2 have recently been reported towards beta Pictoris, a star harbouring a young planetary system. This star is surrounded by a dusty 'debris disk' that is continuously replenished either by collisions between asteroidal objects or by evaporation of ices on Chiron-like objects. A gaseous disk has also been inferred from absorption lines in the stellar spectrum. Here we present the far-ultraviolet spectrum of beta Pictoris, in which H2 absorption lines are not seen. This allows us to set a very low upper limit on the column density of H2: N(H2)/= 1018 cm-2. This non-detection is puzzling when compared to the quantity of H2 inferred from the infrared observations, but it does show that H2 is not in the disk on the direct line of sight. Carbon monoxide (CO) has been seen in absorption against the star, yielding a ratio of CO/H26 x 10-4. As CO would be destroyed under ambient conditions in about 200 years (refs 9, 11), our result demonstrates that the CO in the disk arises from evaporation of planetesimals.
Published: 2001

146. Observations of O VI Emission from the Diffuse Interstellar Medium

Author: Edward B. Jenkins, Donald G. York, J. M. Shull, B-G Andersson, Cecile Gry, William P. Blair, William V. Dixon, H. W. Moos, Blair D. Savage, Alex W. Fullerton, Robin L. Shelton, William R. Oegerle, Jerry Edelstein, Kenneth R. Sembach, David J. Sahnow, Edward M. Murphy, J. C. Howk, Katherine C. Roth, M. S. Oey, Jeffrey L. Linsky, O. H. W. Siegmund, Alfred Vidal-Madjar, Ravi Sankrit, Barry Y. Welsh, Jeffrey W. Kruk, 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), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Ultraviolet: ISM, Electron density, Galaxy: General, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Interstellar medium, Supernova, Local Bubble, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Thick disk, ISM: General, Emission spectrum, Halo, ISM: Structure, Galaxy: Halo, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract: We report the first Far Ultraviolet Spectroscopic Explorer (FUSE) measurements of diffuse O VI (lambda,lambda 1032,1038) emission from the general diffuse interstellar medium outside of supernova remnants or superbubbles. We observed a 30arcsec x 30arcsec region of the sky centered at l = 315 and b = -41. From the observed intensities (2930+/-290(random)+/-410(systematic) and 1790+/-260(random)+/-250(systematic) photons/cm/cm/s/sr in the 1032 and 1038 Angstrom emission lines, respectively), derived equations, and assumptions about the source location, we calculate the intrinsic intensity, electron density, thermal pressure, and emitting depth. The intensities are too large for the emission to originate solely in the Local Bubble. Thus, we conclude that the Galactic thick disk and lower halo also contribute. High velocity clouds are ruled out because there are none near the pointing direction. The calculated emitting depth is small, indicating that the O VI-bearing gas fills a small volume. The observations can also be used to estimate the cooling rate of the hot interstellar medium and constrain models. The data also yield the first intensity measurement of the C II 3s2 S1/2 to 2p2 P3/2 emission line at 1037 Angstroms and place upper limits on the intensities of ultraviolet line emission from C I, C III, Si II, S III, S IV, S VI, and Fe III., 30 pages including 5 figures and 5 tables; submitted to ApJ, October 2000; accepted by ApJ, May 2001
Published: 2001
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147. Is β Pictoris an Active Star?

Author: M. Andre, William P. Blair, H. W. Moos, A. Roberge, Paul D. Feldman, Roger Ferlet, Jean-Claude Bouret, A. Lecavelier des Etangs, Magali Deleuil, Alfred Vidal-Madjar, Scott D. Friedman, 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), Aix Marseille Université (AMU), Institut d'Astrophysique de Paris (IAP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Accretion, Far ultraviolet, Stars: Activity, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Stars: Chromospheres, Stars: Circumstellar Matter, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Ionization, Accretion Disks, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Stars: Individual: Constellation Name: β Pictoris, Astrophysics::Earth and Planetary Astrophysics, Emission spectrum, Chromosphere, Astrophysics::Galaxy Astrophysics, Active star
Abstract: International audience; We present the first emission-line spectrum of β Pictoris, as revealed by the Far Ultraviolet Spectroscopic Explorer satellite. Broad emission lines due to highly ionized species, C III and O VI, are well detected above the very low continuum level. The mere presence of such lines in the β Pic spectrum is evidence of a complex stellar environment, including dense and hot regions. We argue that these spectral features may originate from a solar-like extended chromosphere or from magnetospheric accretion.
Published: 2001
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148. Observation of microlensing toward the galactic spiral arms. EROS II 3 year survey

Author: Franz E. Bauer, A. Milsztajn, N. Regnault, A. Bouquet, Cristina Afonso, X. Charlot, T. Lasserre, J. Haissinski, J. Rich, A. Kim, F. Couchot, David S. Graff, Johannes Andersen, Michel Spiro, J. de Kat, Roger Ferlet, S. Zylberajch, Andrew Gould, C. Loup, D. Hardin, G. Blanc, Marc Moniez, J. P. Beaulieu, L. Vigroux, Christophe Magneville, E. Maurice, Éric Aubourg, J. B. Marquette, M. Gros, Jean-Christophe Hamilton, C. Alard, J. F. Glicenstein, C. Coutures, O. Perdereau, N. Palanque-Delabrouille, L. Le Guillou, P. Fouque, Bertrand Goldman, P. Bareyre, L. Prevot, Alfred Vidal-Madjar, F. Derue, E. Lesquoy, S. Char, B. Mansoux, Reza Ansari, J. N. Albert, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris, Université Paris sciences et lettres (PSL), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Departement de recherche SPAtiale (DESPA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Observatoire Astronomique de Marseille Provence (OAMP), Université de Provence - Aix-Marseille 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and EROS
Subjects: Physics, GALAXY: KINEMATICS AND DYNAMICS, Spiral galaxy, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, GRAVITATIONAL LENSING, Galactic plane, Gravitational microlensing, Galactic tide, Galaxy, Galactic halo, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, Bulge, Galactic corona, Astrophysics::Earth and Planetary Astrophysics, GALAXY: STELLAR CONTENT, GALAXY: STRUCTURE, Astrophysics::Galaxy Astrophysics, GALAXY: BAR
Abstract: International audience; We present an analysis of the light curves of 9.1 million stars observed during three seasons by EROS (Expérience de Recherche d'Objets Sombres), in the Galactic plane away from the bulge. Seven stars exhibit luminosity variations compatible with gravitational microlensing effects due to unseen objects. The corresponding optical depth, averaged over four directions, is bar tau = 0.43 +/- 0.2\ x\ 10-6. While this value is compatible with expectations from simple Galactic models under reasonable assumptions on the target star distances, we find an excess of events with short timescales toward the direction closest to the Galactic centre. We discuss a possible interpretation involving the contribution of an elongated bar. This work is based on observations made with the MARLY telescope at the European Southern Observatory, La Silla, Chile.
Published: 2001
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149. FUSE and Deuterated Molecular Hydrogen

Author: Roger Ferlet, G. Pineau des Forêts, E. Roueff, G. Hebrard, Alfred Vidal-Madjar, M. Andre, A. Lecavelier, and Martin Lemoine
Subjects: Physics, Fuse (automotive), Deuterium, Chemical physics, Hydrogen molecule, Astrophysics, Space (mathematics)
Published: 2000
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150. Deuterium abundances

Author: Roger Ferlet, Edward B. Jenkins, Martin Lemoine, D. G. York, K. R. Sembach, W. Moos, L. Ben Jaffel, George Sonneborn, Jean Audouze, Alfred Vidal-Madjar, C. Mallouris, P. D. Feldman, and G. Hebrard
Subjects: Physics, Solar System, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Redshift, Interstellar medium, Deuterium, Space and Planetary Science, Abundance (ecology), Astrophysics::Solar and Stellar Astrophysics, Instrumentation, Astrophysics::Galaxy Astrophysics
Abstract: We discuss the measurements of deuterium abundances in high redshift quasar absorbers, in the solar system and in the interstellar medium. We present new results that indicate spatial variations of the deuterium abundance in the interstellar medium at the level of 50% over scales possibly as small as 10 pc, and discuss plausible causes for the origin of these variations., 19 pages, 1 figure. To appear in New Astronomy, for the David N. Schramm memorial volume
Published: 1999

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