2,178 research outputs found

    In Search of the Anglophone Doctor in Jacques Ferron’s Story “Le petit William”

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    The story of ‘Le Petit William’ (Contes anglais, 1964) is based on Ferron’s experiences as a general practitioner in the GaspĂ© in 1946. A medical event, use of the maternal left lateral position by a sage-femme to deliver a baby boy, becomes allegory. The sage-femme had learned the technique from a visiting Anglophone doctor. A simple joke, which superficially appears to be the story’s culmination, takes on a sombre political tone when considered in the light of the Latin epigraph. Trips to the GaspĂ©, a review of the history of obstetrics and speculation are used in this paper to understand the realities upon which Ferron’s fantastic literature is based. A la recherche du mĂ©decin « anglais » dans ‘Le petit William’ de Jacques Ferron L\u27histoire de « Le Petit William » (Contes anglais,1964) est basĂ©e sur les expĂ©riences de Ferron comme mĂ©decin de campagne en GaspĂ©sie en 1946. Un Ă©vĂ©nement mĂ©dical, l\u27usage de la posture obstĂ©tricale « position latĂ©rale gauche » par une sage-femme lors de la naissance d’un petit garçon, donne lieu Ă  une allĂ©gorie. La sage-femme avait appris la technique d\u27un accoucheur « anglais», de passage dans la rĂ©gion. Une plaisanterie simple, qui semble Ă  premiĂšre vue ĂȘtre la culmination de l\u27histoire, prend un ton politique plutĂŽt sombre quand on la considĂšre Ă  la lumiĂšre de l\u27Ă©pigraphe latine. Partant de renseignements recueillis lors de voyages en GaspĂ©sie, d’une revue de l\u27histoire obstĂ©tricale, et de la spĂ©culation, nous essaierons de comprendre les rĂ©alitĂ©s sur lesquelles la littĂ©rature fantastique de Ferron est basĂ©e

    Speckle and Spectroscopic Orbits of the Early A-Type Triple System in Virginis

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    Eta Virginis is a bright (V = 3.89) triple system of composite spectral type A2 IV that has been observed for over a dozen years with both spectroscopy and speckle interferometry. Analysis of the speckle observations results in a long period of 13.1 yr. This period is also detected in residuals from the spectroscopic observations of the 71.7919 day short-period orbit. Elements of the long-period orbit were determined separately using the observations of both techniques. The more accurate elements from the speckle solution have been assumed in a simultaneous spectroscopic determination of the short- and long-period orbital elements. The magnitude difference of the speckle components suggests that lines of the third star should be visible in the spectrum

    The Past and Future History of Regulus

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    We show how the recent discovery of a likely close white dwarf companion to the well known star Regulus, one of the brightest stars in the sky, leads to considerable insight into the prior evolutionary history of this star, including the cause of its current rapid rotation. We infer a relatively narrow range for the initial masses of the progenitor system: M_{10} = 2.3 +/- 0.2 M_sun and M_{20} = 1.7 +/- 0.2 M_sun, where M_{10} and M_{20} are the initial masses of the progenitors of the white dwarf and Regulus, respectively. In this scenario, the age of the Regulus system would exceed 1 Gyr. We also show that Regulus, with a current orbital period of 40 days, has an interesting future ahead of it. This includes (i) a common envelope phase, and, quite possibly, (ii) an sdB phase, followed by (iii) an AM CVn phase with orbital periods < 1 hr. Binary evolution calculations are presented in support of this scenario. We also discuss alternative possibilities, emphasizing the present uncertainties in binary evolution theory. Thus, this one particular star system illustrates many different aspects of binary stellar evolution.Comment: PDFLaTeX, 9 pages with 8 figure

    Structural Properties and Relative Stability of (Meta)Stable Ordered, Partially-ordered and Disordered Al-Li Alloy Phases

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    We resolve issues that have plagued reliable prediction of relative phase stability for solid-solutions and compounds. Due to its commercially important phase diagram, we showcase Al-Li system because historically density-functional theory (DFT) results show large scatter and limited success in predicting the structural properties and stability of solid-solutions relative to ordered compounds. Using recent advances in an optimal basis-set representation of the topology of electronic charge density (and, hence, atomic size), we present DFT results that agree reasonably well with all known experimental data for the structural properties and formation energies of ordered, off-stoichiometric partially-ordered and disordered alloys, opening the way for reliable study in complex alloys.Comment: 7 pages, 2 figures, 2 Table

    Separated Fringe Packet Observations with the CHARA Array II: ω\omega Andromeda, HD 178911, and {\xi} Cephei

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    When observed with optical long-baseline interferometers (OLBI), components of a binary star which are sufficiently separated produce their own interferometric fringe packets; these are referred to as Separated Fringe Packet (SFP) binaries. These SFP binaries can overlap in angular separation with the regime of systems resolvable by speckle interferometry at single, large-aperture telescopes and can provide additional measurements for preliminary orbits lacking good phase coverage, help constrain elements of already established orbits, and locate new binaries in the undersampled regime between the bounds of spectroscopic surveys and speckle interferometry. In this process, a visibility calibration star is not needed, and the separated fringe packets can provide an accurate vector separation. In this paper, we apply the SFP approach to {\omega} Andromeda, HD 178911, and {\xi} Cephei with the CLIMB three-beam combiner at the CHARA Array. For these systems we determine component masses and parallax of 0.963±{\pm}0.049 M⊙M_{\odot} and 0.860±{\pm}0.051 M⊙M_{\odot} and 39.54±{\pm}1.85 milliarcseconds (mas) for {\omega} Andromeda, for HD 178911 of 0.802±{\pm}0.055 M⊙M_{\odot} and 0.622±{\pm}0.053 M⊙M_{\odot} with 28.26±{\pm}1.70 mas, and masses of 1.045±{\pm}0.031 M⊙M_{\odot} and 0.408±{\pm}0.066 M⊙M_{\odot} and 38.10±{\pm}2.81 mas for {\xi} Cephei.Comment: 28 pages, 4 tables, 6 figures, accepted to AJ May 201

    Radial Structure in the TW Hya Circumstellar Disk

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    We present new near-infrared interferometric data from the CHARA array and the Keck Interferometer on the circumstellar disk of the young star, TW Hya, a proposed "transition disk." We use these data, as well as previously published, spatially resolved data at 10 ÎŒm and 7 mm, to constrain disk models based on a standard flared disk structure. We find that we can match the interferometry data sets and the overall spectral energy distribution with a three-component model, which combines elements at spatial scales proposed by previous studies: optically thin, emission nearest the star, an inner optically thick ring of emission at roughly 0.5 AU followed by an opacity gap and, finally, an outer optically thick disk starting at ~4 AU. The model demonstrates that the constraints imposed by the spatially resolved data can be met with a physically plausible disk but this requires a disk containing not only an inner gap in the optically thick disk as previously suggested, but also a gap between the inner and outer optically thick disks. Our model is consistent with the suggestion by Calvet et al. of a planet with an orbital radius of a few AU. We discuss the implications of an opacity gap within the optically thick disk

    HR 266=ADS 784: an Early Type Spectroscopic, Speckle Astrometric Multiple System

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    The detection and nature of a \u27speckle astrometric\u27 system are reported with attention given to alternative interpretations of the system components. The HR 226 = ADS 784 system is described as a short-period binary (with a period of 4.241148 +/- 0.000008 d) orbiting an unseen companion (with a period of 1769 +/- 10 d), and the triple\u27s visual orbit is 83.10 +/- 0.20 yr. The elements of the various orbits taken from spectroscopic data are employed to develop the model scenarios. The masses and spectral types of the components are developed and used to calculate the inclinations of the short-, intermediate-, and long-period orbits. The computations show that the inclinations are similar and can be interpreted as three coplanar orbits; however, this conclusion suggests that the unseen companion\u27s absorption features should be detectable. Since the absorption features are not detectable it is concluded that the unseen companion is either a pair of late-type lower-mass stars or one rapidly rotating star

    The fundamental parameters of the roAp star 10 Aql

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    Due to the strong magnetic field and related abnormal surface layers existing in rapidly oscillating Ap stars, systematic errors are likely to be present when determining their effective temperatures, which potentially compromises asteroseismic studies of these pulsators. Using long-baseline interferometry, our goal is to determine accurate angular diameters of a number of roAp targets to provide a temperature calibration for these stars. We obtained interferometric observations of 10 Aql with the visible spectrograph VEGA at the CHARA array. We determined a limb-darkened angular diameter of 0.275+/-0.009 mas and deduced a linear radius of 2.32+/-0.09 R_sun. We estimated the star's bolometric flux and used it, in combination with its parallax and angular diameter, to determine the star's luminosity and effective temperature. For two data sets of bolometric flux we derived an effective temperature of 7800+/-170 K and a luminosity of 18+/-1 L_sun or of 8000+/-210 K and 19+/-2 L_sun. We used these fundamental parameters together with the large frequency separation to constrain the mass and the age of 10 Aql, using the CESAM stellar evolution code. Assuming a solar chemical composition and ignoring all kinds of diffusion and settling of elements, we obtained a mass of 1.92 M_sun and an age of 780 Gy or a mass of 1.95 M_sun and an age of 740 Gy, depending on the considered bolometric flux. For the first time, we managed to determine an accurate angular diameter for a star smaller than 0.3 mas and to derive its fundamental parameters. In particular, by only combining our interferometric data and the bolometric flux, we derived an effective temperature that can be compared to those derived from atmosphere models. Such fundamental parameters can help for testing the mechanism responsible for the excitation of the oscillations observed in the magnetic pulsating stars

    Multiplicity of Galactic Cepheids from long-baseline interferometry~III. Sub-percent limits on the relative brightness of a close companion of ÎŽ\delta~Cephei

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    We report new CHARA/MIRC interferometric observations of the Cepheid archetype ÎŽ\delta Cep, which aimed at detecting the newly discovered spectroscopic companion. We reached a maximum dynamic range ΔH\Delta H = 6.4, 5.8, and 5.2 mag, respectively within the relative distance to the Cepheid r<25r < 25 mas, 25<r<5025 < r < 50 mas and 50<r<10050 < r < 100 mas. Our observations did not show strong evidence of a companion. We have a marginal detection at 3σ3\sigma with a flux ratio of 0.21\%, but nothing convincing as we found other possible probable locations. We ruled out the presence of companion with a spectral type earlier than F0V, A1V and B9V, respectively for the previously cited ranges rr. From our estimated sensitivity limits and the Cepheid light curve, we derived lower-limit magnitudes in the HH band for this possible companion to be Hcomp>9.15,8.31H_\mathrm{comp} > 9.15, 8.31 and 7.77 mag, respectively for r<25r < 25 mas, 25<r<5025 < r < 50 mas and 50<r<10050 < r < 100 mas. We also found that to be consistent with the predicted orbital period, the companion has to be located at a projected separation <24< 24 mas with a spectral type later than a F0V star.Comment: Accepted for publication in MNRA