Conclusions: CoRoT observations are supplying seismic constraints for the most populated class of He-burning stars in the galactic disk. This opens a new access gate to probing the properties of red-giant stars that, coupled with classical observations, promises to extend our knowledge of these advanced phases of stellar evolution and to add relevant constraints to models of composite stellar populations in the Galaxy. The CoRoT space mission was developed and is operated by the French space agency CNES, with the participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. [less ▲]Detailed reference viewed: 14 (0 ULg) Asteroseismology of red-clump stars with CoRoT and KeplerMiglio, Andrea ; Montalban Iglesias, Josefa ; Eggenberger, P. et alin AIP Conference Proceedings (2009), 1170The availability of asteroseismic constraints for a large number of red giants with CoRoT and, in the near future with Kepler, paves the way for detailed studies of populations of galactic-disk red giants ... [more ▼]The availability of asteroseismic constraints for a large number of red giants with CoRoT and, in the near future with Kepler, paves the way for detailed studies of populations of galactic-disk red giants. We investigate which information on the observed population can be recovered by the distribution of the observed seismic constraints: the frequency of maximum power of solar-like oscillations (νmax) and the large frequency separation (Δν). We use the distribution of νmax and of Δν observed by CoRoT in nearly 800 red giants in the first long observational run, as a tool to investigate the properties of galactic red-giant stars through the comparison with simulated distributions based on synthetic stellar populations. We can clearly identify the bulk of the red giants observed by CoRoT as red-clump stars, i.e. post-flash core-He-burning stars. The distribution of νmax and of Δν give us access to the distribution of the stellar radius and mass, and thus represent a most promising probe of the age and star formation rate of the disk, and of the mass-loss rate during the red-giant branch. This approach will be of great utility also in the interpretation of forthcoming surveys of variability of red giants with CoRoT and Kepler. In particular, an asteroseismic mass estimate of clump stars in the old-open clusters observed by Kepler, would represent a most valuable observational test of the poorly known mass-loss rate on the giant branch, and of its dependence on metallicity. [less ▲]Detailed reference viewed: 11 (0 ULg) Decoding of the light changes in eclipsing Wolf-Rayet binaries. I. A non-classical approach to the solution of light curvesPerrier, C.; Breysacher, J.; Rauw, Grégor in Astronomy and Astrophysics (2009), 503Aims. We present a technique to determine the orbital and physical parameters of eclipsing eccentric Wolf-Rayet + O-star binaries, where one eclipse is produced by the absorption of the O-star light by ... [more ▼]Aims. We present a technique to determine the orbital and physical parameters of eclipsing eccentric Wolf-Rayet + O-star binaries, where one eclipse is produced by the absorption of the O-star light by the stellar wind of the W-R star. Methods: Our method is based on the use of the empirical moments of the light curve that are integral transforms evaluated from the observed light curves. The optical depth along the line of sight and the limb darkening of the W-R star are modelled by simple mathematical functions, and we derive analytical expressions for the moments of the light curve as a function of the orbital parameters and the key parameters of the transparency and limb-darkening functions. These analytical expressions are then inverted in order to derive the values of the orbital inclination, the stellar radii, the fractional luminosities, and the parameters of the wind transparency and limb-darkening laws. Results: The method is applied to the SMC W-R eclipsing binary HD 5980, a remarkable object that underwent an LBV-like event in August 1994. The analysis refers to the pre-outburst observational data. A synthetic light curve based on the elements derived for the system allows a quality assessment of the results obtained. [less ▲]Detailed reference viewed: 21 (8 ULg) Optical spectroscopy of X-Mega targets in the Carina nebula - VII. On the multiplicity of Tr16-112, HD93343 and HD93250Rauw, Grégor ; Nazé, Yaël ; Fernández Lajús, E. et alin Monthly Notices of the Royal Astronomical Society (2009), 398We present the results of a spectroscopic monitoring campaign devoted to three O-type stars in the Carina nebula. We derive the full SB2 orbital solution of the binary system Tr16-112, an exceptional ... [more ▼]We present the results of a spectroscopic monitoring campaign devoted to three O-type stars in the Carina nebula. We derive the full SB2 orbital solution of the binary system Tr16-112, an exceptional dissymmetrical system consisting of an O5.5-6V((f[SUP]+[/SUP]?p)) primary and a B2V-III secondary. We also report on low-amplitude brightness variations in Tr16-112 that are likely due to the ellipsoidal shape of the O5.5-6 primary revolving in an eccentric orbit around the system's centre of mass. We detect for the first time a clear SB2 binary signature in the spectrum of HD93343 (O8 + O8), although our data are not sufficient to establish an orbital solution. This system also displays low-amplitude photometric modulations. On the other hand, no indication of multiplicity is found in the optical spectra of HD93250. Finally, we discuss the general properties of multiple massive stars in the Carina OB1 association. Based on observations collected at the European Southern Observatory (La Silla, Chile), at Complejo Astronómico El Leoncito (Argentina), at the Cerro Tololo Inter-American Observatory (CTIO) and with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). E-mail: rauw@astro.ulg.ac.be â ¡ Research Associate FRS/FNRS (Belgium). § Postdoctoral Researcher FRS/FNRS (Belgium). ¶ Senior Research Associate FRS/FNRS (Belgium). [less ▲]Detailed reference viewed: 47 (10 ULg) Multi-wavelength observations of afterglow of GRB 080319B and the modeling constraintsPandey, S. B.; Castro-Tirado, A. J.; Jelínek, M. et alin Astronomy and Astrophysics (2009), 504(1), 45-51We present observations of the afterglow of GRB 080319B at optical, mm and radio frequencies from a few hours to 67 days after the burst. Present observations along with other published multi-wavelength ... [more ▼]We present observations of the afterglow of GRB 080319B at optical, mm and radio frequencies from a few hours to 67 days after the burst. Present observations along with other published multi-wavelength data have been used to study the light-curves and spectral energy distributions of the burst afterglow. The nature of this brightest cosmic explosion has been explored based on the observed properties and it's comparison with the afterglow models. Our results show that the observed features of the afterglow fits equally good with the Inter Stellar Matter and the Stellar Wind density profiles of the circum-burst medium. In case of both density profiles, location of the maximum synchrotron frequency $\nu_m$ is below optical and the value of cooling break frequency $\nu_c$ is below $X-$rays, $\sim 10^{4}$s after the burst. Also, the derived value of the Lorentz factor at the time of naked eye brightness is $\sim 300$ with the corresponding blast wave size of $\sim 10^{18}$ cm. The numerical fit to the multi-wavelength afterglow data constraints the values of physical parameters and the emission mechanism of the burst. [less ▲]Detailed reference viewed: 107 (6 ULg) A Fuzzy Metric for Assessing the Producibility of Straightening in Early DesignCaprace, Jean-David ; Aracil Fernandez, Francisco; Losseau, Nicolas et alin The 14th International Conference on Computer Applications in Shipbuilding (ICCAS) (2009, September 01)Since several years, the large shipyards use more and more thin plates to build up stiffened panels in order to decrease the structural weight. The major problem relating to the utilization of thin plates ... [more ▼]Since several years, the large shipyards use more and more thin plates to build up stiffened panels in order to decrease the structural weight. The major problem relating to the utilization of thin plates is the occurrence of welding distortions that have to be eliminated for esthetical and service reasons. This straightening operation involves significant costs and it seems thus important to characterize its economical impact on the global hull fabrication. This paper presents a way to minimize cost in shipbuilding industry by the implementation of a producibility fuzzy metric in order to obtain a better knowledge of the straightening process. Attention has been focused on the definition of fuzzy rules by experts but also on the optimisation of the decision surface to reduce the error compared to actual measurement points. [less ▲]Detailed reference viewed: 106 (16 ULg) WASP-16b: A New Jupiter-Like Planet Transiting a Southern Solar AnalogLister, T. A.; Anderson, D. R.; Gillon, Michaël et alin Astrophysical Journal (2009), 703We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity ... [more ▼]We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity spectroscopic data leads to a planet with R [SUB]p[/SUB] = 1.008 ± 0.071 R [SUB]Jup[/SUB] and M [SUB]p[/SUB] = 0.855 ± 0.059 M [SUB]Jup[/SUB], orbiting a host star with R [SUB]*[/SUB] = 0.946 ± 0.054 R [SUB]sun[/SUB] and M [SUB]*[/SUB] = 1.022 ± 0.101 M [SUB]sun[/SUB]. Comparison of the high resolution stellar spectrum with synthetic spectra and stellar evolution models indicates the host star is a near-solar metallicity ([Fe/H] =0.01 ± 0.10) solar analog (T [SUB]eff[/SUB] = 5700 ± 150 K and log g = 4.5 ± 0.2) of intermediate age (tau = 2.3[SUP]+5.8[/SUP] [SUB]--2.2[/SUB] Gyr). [less ▲]Detailed reference viewed: 58 (1 ULg) X-ray spectroscopy of starsGuedel, Manuel; Nazé, Yaël in Astronomy and Astrophysics Review (2009), 17Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Their X-ray spectra have been important in constraining physical processes that heat plasma in stellar environments to ... [more ▼]Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Their X-ray spectra have been important in constraining physical processes that heat plasma in stellar environments to temperatures exceeding one million degrees. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense, of X-ray spectra from the solar corona. The Sun itself as a typical example of a main-sequence cool star has been a pivotal testbed for physical models to be applied to cool stars. X-ray emission from cool stars is indeed ascribed to magnetically trapped hot gas analogous to the solar coronal plasma, although plasma parameters such as temperature, density, and element abundances vary widely. Coronal structure, its thermal stratification and geometric extent can also be interpreted based on various spectral diagnostics. New features have been identified in pre-main sequence stars; some of these may be related to accretion shocks on the stellar surface, fluorescence on circumstellar disks due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot stars clearly dominate the interaction with the galactic interstellar medium: they are the main sources of ionizing radiation, mechanical energy and chemical enrichment in galaxies. High-energy emission permits to probe some of the most important processes at work in these stars, and put constraints on their most peculiar feature: the stellar wind. Medium and high- resolution spectroscopy have shed new light on these objects as well. Here, we review recent advances in our understanding of cool and hot stars through the study of X-ray spectra, in particular high-resolution spectra now available from XMM -Newton and Chandra. We address issues related to coronal structure, flares, the composition of coronal plasma, X-ray production in accretion streams and outflows, X-rays from single OB-type stars, massive binaries, magnetic hot objects and evolved WR stars. [less ▲]Detailed reference viewed: 25 (2 ULg) Concurrent observations of the ultraviolet nitric oxide and infrared O[SUB]2[/SUB] nightglow emissions with Venus ExpressGérard, Jean-Claude ; Cox, Cédric ; Soret, Lauriane et alin Journal of Geophysical Research. Planets (2009), 114Two prominent features of the Venus nightside airglow are the nitric oxide delta and gamma bands produced by radiative association of O and N atoms in the lower thermosphere and the O[SUB]2[/SUB] infrared ... [more ▼]Two prominent features of the Venus nightside airglow are the nitric oxide delta and gamma bands produced by radiative association of O and N atoms in the lower thermosphere and the O[SUB]2[/SUB] infrared emission generated by three-body recombination of oxygen atoms in the upper mesosphere. The O[SUB]2[/SUB] airglow has been observed from the ground, during the Cassini flyby, and with VIRTIS on board Venus Express. It now appears that the global structure of the two emissions shows some similarities, but the statistical location of the region of strongest emission is not coincident. The Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) ultraviolet spectrograph has collected a large number of spectra of the Venus nitric oxide nightside airglow. Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) images have been obtained at the limb and in the nadir-viewing mode and have provided new information on the horizontal and vertical distribution of the emission. We present the first concurrent observations of the two emissions observed with Venus Express. We show that nadir observations generally indicate a low degree of correlation between the two emissions observed quasi-simultaneously at a common location. A statistical study of limb profiles indicates that the altitude and the brightness of the two airglow layers generally do not covary. We suggest that this lack of correlation is explained by the presence of strong horizontal winds in the mesosphere-thermosphere transition region. They carry the downflowing atoms over large distances in such a way that regions of enhanced NO emission generally do not coincide with zones of bright O[SUB]2[/SUB] airglow. [less ▲]Detailed reference viewed: 33 (16 ULg) The Enigma of B-type Pulsators in the SMCSalmon, Sébastien ; Montalban Iglesias, Josefa ; Miglio, Andrea et alin AIP Conference Proceedings (2009, September 01), 1170Since the early nineties it is accepted that the excitation mechanism of B-type pulsators on the main sequence is due to the opacity peak in the iron-group elements at T~200,000 K. The Fe content plays ... [more ▼]Since the early nineties it is accepted that the excitation mechanism of B-type pulsators on the main sequence is due to the opacity peak in the iron-group elements at T~200,000 K. The Fe content plays then a major role in the excitation of β Cep and SPB pulsations. While theoretical non-adiabatic computations predict no β Cep pulsators and only a small number of SPBs for low metallicity environments such as that of the Magellanic Clouds (MCs), recent variability surveys of B stars in the SMC have reported the detection of a significant number of SPB and β Cep candidates. Since the SMC is the metal poorest (Z~0001-0.004) of the MCs, it constitutes an interesting object for investigating the disagreement between theory and observations. We approach the problem by calling into question some of the hypotheses made in previous studies: given the different chemical evolution of the SMC compared with our local galactic environment, is it appropriate to describe the chemical composition of SMC B stars by scaling the solar mixture to lower Z? Is that composition uniform in space and time? In this paper we present the results of a stability analysis of B-type stellar models computed with a revised chemical composition and metallicity specific to the SMC. [less ▲]Detailed reference viewed: 52 (14 ULg) Le chant comme support à l’acquisition du langage : Effets de l’expertise musicale ou linguistiqueLarrouy, Pauline Master's dissertation (2009)Le chant, omniprésent dans notre vie, constitue également un matériel écologique et multidimensionnel qui allie les dimensions musicale et linguistique. Il offre ainsi un outil privilégié pour observer ... [more ▼]Le chant, omniprésent dans notre vie, constitue également un matériel écologique et multidimensionnel qui allie les dimensions musicale et linguistique. Il offre ainsi un outil privilégié pour observer les relations entre la musique et le langage. Afin d’examiner la spécificité du traitement des informations langagières et musicales dans le chant, nous avons étudié l’influence de l’expertise musicale ou langagière sur l’utilisation des probabilités transitionnelles, un type d’apprentissage statistique implicite particulièrement important dans le développement langagier. Dans le but d’étudier l’intervention de modulations fréquentielles dans l’utilisation des propriétés statistiques des syllabes, Schön, Boyer, Moreno, Besson, Peretz et Kolinsky (2008) avaient mis au point une méthode astucieuse et ont ouvert la voie à l’expérimentation du bénéfice du chant dans l’acquisition du langage. Grâce à leur matériel et à la conception d’une expérience exploratoire, nous avons comparé les performances de sujets non-experts, experts en musique et experts en langage dans l’utilisation des probabilités transitionnelles d’un matériel linguistique et musical. Schön et al (2008) avaient mis en évidence le bénéfice des propriétés structurales et motivationnelles de la musique contenues dans le chant. Nos résultats ne répliquent pas cette étude chez des non-experts mais une interaction significative apparaît entre les expériences proposées et le type d’expertise. Les experts en musique semblent bénéficier des informations musicales et linguistiques pour l’apprentissage statistique lorsqu’elles sont présentées de manière congruente. Par ailleurs, une incongruité entre l’information linguistique et musicale aiderait les experts en langage à utiliser des probabilités transitionnelles de la parole. Les différentes analyses ont guidé notre réflexion sur la spécificité du traitement des paroles et de la mélodie contenues dans le chant. La discussion relative aux effets observés permet d’envisager de futures recherches dans ce domaine et l’exploration de la musicalité de la parole dans une perspective de clinique logopédique. [less ▲]Detailed reference viewed: 328 (2 ULg) Expression of aryl hydrocarbon receptor (AHR) and AHR-interacting protein in pituitary adenomas: pathological and clinical implications.Jaffrain-Rea, M. L.; Angelini, M.; Gargano, D. et alin Endocrine-Related Cancer (2009), 16(3), 1029-1043Germline mutations of the aryl hydrocarbon receptor (AHR)-interacting protein (AIP) gene confer a predisposition to pituitary adenomas (PA), usually in the setting of familial isolated PA. To provide ... [more ▼]Germline mutations of the aryl hydrocarbon receptor (AHR)-interacting protein (AIP) gene confer a predisposition to pituitary adenomas (PA), usually in the setting of familial isolated PA. To provide further insights into the possible role of AIP in pituitary tumour pathogenesis, the expression of AIP and AHR was determined by real-time RT-PCR and/or immunohistochemistry (IHC) in a large series of PA (n=103), including 17 with AIP mutations (AIP(mut)). Variable levels of AIP and AHR transcripts were detected in all PA, with a low AHR expression (P<0.0001 versus AIP). Cytoplasmic AIP and AHR were detected by IHC in 84.0 and 38.6% of PA respectively, and significantly correlated with each other (P=0.006). Nuclear AHR was detected in a minority of PA (19.7%). The highest AIP expression was observed in somatotrophinomas and non-secreting (NS) PA, and multivariate analysis in somatotrophinomas showed a significantly lower AIP immunostaining in invasive versus non-invasive cases (P=0.019). AIP expression was commonly low in other secreting PA. AIP immunostaining was abolished in a minority of AIP(mut) PA, with a frequent loss of cytoplasmic AHR and no evidence of nuclear AHR. In contrast, AIP overexpression in a subset of NS PA could be accompanied by nuclear AHR immunopositivity. We conclude that down-regulation of AIP and AHR may be involved in the aggressiveness of somatotrophinomas. Overall, IHC is a poorly sensitive tool for the screening of AIP mutations. Data obtained on AHR expression suggest that AHR signalling may be differentially affected according to PA phenotype. [less ▲]Detailed reference viewed: 40 (10 ULg)