Publications of Jean-Marie Vreux
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See detailCoordinated monitoring of the eccentric O-star binary Iota Orionis: optical spectroscopy and photometry
Marchenko, Sergey V; Rauw, Grégor ULiege; Antokhina, Eleonora A et al

in Monthly Notices of the Royal Astronomical Society (2000), 317

With the objective of investigating the wind-wind collision phenomenon and supporting contemporaneous X-ray observations, we have organized a large-scale, coordinated optical monitoring campaign of the ... [more ▼]

With the objective of investigating the wind-wind collision phenomenon and supporting contemporaneous X-ray observations, we have organized a large-scale, coordinated optical monitoring campaign of the massive, highly eccentric O9III+B1III binary Iota Orionis. Successfully separating the spectra of the components, we refine the orbital elements and confirm the rapid apsidal motion in the system. We also see strong interaction between the components during periastron passage and detect phase-locked variability in the spectrum of the secondary star. However, we find no unambiguous signs of the bow shock crashing on the surface of the secondary, despite the predictions of hydrodynamic simulations. Combining all available photometric data, we find rapid, phase-locked variations and model them numerically, thus restricting the orbital inclination to 50°<~i<~70°. [less ▲]

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See detailSimulations of observations with the Optical Monitor of the X-ray Multi-Mirror Satellite
Royer, P.; Manfroid, Jean ULiege; Gosset, Eric ULiege et al

in Astronomy and Astrophysics. Supplement Series (2000), 145

This paper addresses the question of the observations to be performed with the Optical Monitor (OM) of the X-ray Multi-Mirror Satellite (XMM) under several aspects. First, we discuss XMM-OM's photometric ... [more ▼]

This paper addresses the question of the observations to be performed with the Optical Monitor (OM) of the X-ray Multi-Mirror Satellite (XMM) under several aspects. First, we discuss XMM-OM's photometric system and its colour transformations towards the standard U BV system. Second, we establish a set of procedures to determine the temperature and the amount of interstellar absorption affecting the observed stars. Last, we address the possibility of isolating quasars in multidimensional colour diagrams based on the XMM-OM filter set. [less ▲]

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See detailA new orbital solution for the massive binary system HD 93403
Rauw, Grégor ULiege; Sana, H.; Gosset, Eric ULiege et al

in Astronomy and Astrophysics (2000), 360

We present a spectroscopic analysis of the early-type massive binary system HD 93403. Using high resolution optical spectra, we clearly separate the primary and secondary components. For the first time ... [more ▼]

We present a spectroscopic analysis of the early-type massive binary system HD 93403. Using high resolution optical spectra, we clearly separate the primary and secondary components. For the first time, we are able to provide an orbital solution for both stars. Our new orbital parameters show discrepancies with the previous solution published by Thackeray & Emerson (?). We further discuss several spectral features of HD 93403. We finally derive qualitative constraints on the inclination of the system and we discuss its evolutionary status and the position of both components in the Hertzsprung-Russell diagram. Based on observations collected at the European Southern Observatory (La Silla, Chile) and the Cerro Tololo Inter-American Observatory (CTIO). [less ▲]

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See detailThe Interacting Early-Type Binary BD +40°4220 (V729 Cyg): Modeling the Colliding Winds Region
Rauw, Grégor ULiege; Vreux, Jean-Marie ULiege; Bohannan, B.

in Astrophysical Journal (1999), 517

We present an analysis of an extensive set of spectroscopic observations of the mysterious early-type binary BD +40 deg4220. A new orbital solution is derived from the radial velocities of the absorption ... [more ▼]

We present an analysis of an extensive set of spectroscopic observations of the mysterious early-type binary BD +40 deg4220. A new orbital solution is derived from the radial velocities of the absorption lines. We confirm that the secondary star is highly overluminous for its mass. The absorption lines of both components display phase-locked profile variations, with some of the secondary's lines going into emission between phi=0.20 and phi=0.55. A detailed investigation of the profile variability of the He II lambda4686 emission line reveals that the pattern of variability of this line is very stable. We show that part of the He II lambda4686 emission is produced in the wind interaction region between the stars. Most of the emission lines in the visual spectrum of BD +40 deg4220 display variations that are reminiscent of those observed on the He II lambda4686 line, pointing toward a similar origin. We present numerical simulations of emission-line profiles in a colliding winds binary, showing that an important part of the variability observed in BD +40 deg4220 can be explained by a colliding winds phenomenon. The properties of the wind interaction region can be accounted for if we assume that the secondary star is an evolved object, most probably some kind of Ofpe/WN9 transition star, with a mass loss rate of ~5.5x10^-6 M_solar yr^-1. We finally discuss the fundamental parameters of the binary, concluding that mass transfer must have played a crucial role in the evolution of this system. [less ▲]

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See detailNarrow-band photometry of the eclipsing WN7+O binary WR 22
Royer, P.; Rauw, Grégor ULiege; Manfroid, Jean ULiege et al

in Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies (1999)

In the present paper, we discuss photometric observations of the February 1996 eclipse of the very massive WR+O binary WR 22. Our data were obtained with a set of narrow-band filters, specially designed ... [more ▼]

In the present paper, we discuss photometric observations of the February 1996 eclipse of the very massive WR+O binary WR 22. Our data were obtained with a set of narrow-band filters, specially designed for the study of WR stars. [less ▲]

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See detailNew observational results on the colliding wind WR+O binary WR 30a
Gosset, Eric ULiege; Royer, P.; Rauw, Grégor ULiege et al

in Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies (1999)

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See detailOn the perspectives of using XMM to study fundamental parameters of early-type stars
Rauw, Grégor ULiege; van der Hucht, K. A.; Mewe, R. et al

in Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies (1999)

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See detailLine profile variability in the spectrum of the O(f) supergiant HD 192639
Rauw, Grégor ULiege; Vreux, Jean-Marie ULiege

in Astronomy and Astrophysics (1998), 335

We report the results of a medium-resolution spectroscopic investigation of the O(f) supergiant HD 192639. Particular attention is paid to the He {ii}\ lambda 4686 line. This line displays strong profile ... [more ▼]

We report the results of a medium-resolution spectroscopic investigation of the O(f) supergiant HD 192639. Particular attention is paid to the He {ii}\ lambda 4686 line. This line displays strong profile variability on time scales of a few days, changing from a P-Cygni profile with a double-peaked emission component to a pure blue-shifted emission line. It appears that the variability of most of the absorption lines present in our spectra is correlated to the deformation of the He {ii}\ lambda 4686 line and arises probably from a large scale structure in the low-velocity part of the stellar wind rather than from a photospheric phenomenon. We find that the time scale of the variability could be consistent with the estimated rotational period of HD 192639. Based on observations collected at the Observatoire de Haute Provence, France. [less ▲]

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See detailA dedicated photometric system for the classification of Wolf-Rayet stars
Royer, P.; Vreux, Jean-Marie ULiege; Manfroid, Jean ULiege

in Astronomy and Astrophysics. Supplement Series (1998), 130

We present here tests of a five-filter photometric system aimed at WR classification. In addition to the well-known easy separation between the WN and WC spectral types, these tests indicate interesting ... [more ▼]

We present here tests of a five-filter photometric system aimed at WR classification. In addition to the well-known easy separation between the WN and WC spectral types, these tests indicate interesting potentialities in the discrimination of subgroups among the WN and the WC which look well related to the classical subtypes. The proposed combinations of filters (or derived ones) bear enough discriminating power to satisfy some evolutionary studies in crowded fields where spectroscopic follow-up is not possible. Based on observations collected at the European Southern Observatory, La Silla, Chile. [less ▲]

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See detailA photometric method to study the Wolf-Rayet content of compact H II regions in nearby galaxies
Royer, P.; Vreux, Jean-Marie ULiege; Manfroid, Jean ULiege

in The Magellanic Clouds and Other Dwarf Galaxies (1998)

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See detailX-Ray Spectroscopy with XMM: A New Powerful Tool to Determine Fundamental Parameters of Early-type Stars
Mewe, R.; Rauw, Grégor ULiege; van der Hucht, K. A. et al

(1998)

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See detailSearch for Interacting Winds in the WN7 + O Binary WR 22
Rauw, Grégor ULiege; Vreux, Jean-Marie ULiege; Gosset, Eric ULiege

in Revista Mexicana de Astronomia y Astrofisica Conference Series (1996, December 01)

We present new spectroscopic observations of the He I Lambda5876 line in WR22 which were obtained around periastron. These data show strong line profile variability. We use recently determined orbital ... [more ▼]

We present new spectroscopic observations of the He I Lambda5876 line in WR22 which were obtained around periastron. These data show strong line profile variability. We use recently determined orbital elements of WR22 to discuss the possibility of tidal interactions or of a colliding wind phenomenon affecting the outer parts of the Wolf-Rayet atmosphere. [less ▲]

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See detailExistence of a short period (3.5-4 hours) in the photometric variability of WR 66.
Rauw, Grégor ULiege; Gosset, Eric ULiege; Manfroid, Jean ULiege et al

in Astronomy and Astrophysics (1996), 306

We report here on an independent detection of a short period (~4hours) in the photometric variations of WR66, thus confirming in broad terms the discovery by Antokhin et al.. In addition, we present the ... [more ▼]

We report here on an independent detection of a short period (~4hours) in the photometric variations of WR66, thus confirming in broad terms the discovery by Antokhin et al.. In addition, we present the first spectroscopic variability analysis for this star. A few peculiarities of the spectrum of WR66 are also discussed. Finally, we perform a brief examination of different possible origins of the phenomenon. [less ▲]

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See detailWR22: the most massive Wolf-Rayet star ever weighed.
Rauw, Grégor ULiege; Vreux, Jean-Marie ULiege; Gosset, Eric ULiege et al

in Astronomy and Astrophysics (1996), 306

The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of the ... [more ▼]

The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of the orbit, formerly determined on the basis of photographic spectra. The high signal-to-noise ratio of our data also allows the detection of some weak absorption lines which, for the first time, can definitely be attributed to the companion. A study of their radial velocities gives a mass ratio of m_WR_/m_O_=2.78 leading to a minimum mass of 72M[SUB]sun[/SUB]_ for the WN7 star. The companion can be classified as a "late O" (O6.5-O8.5) star with a luminosity ratio of the system q=L_WR_^y^/L_O_^y^ at 5500A of about 8. The exceptionally high mass of the WN7 star and its high hydrogen mass-fraction suggest that WR22 is at the beginning of its Wolf-Rayet evolution. As a matter of fact, with such a high mass, WR22 most probably is still a hydrogen burning object. Therefore, the WN7 component is much closer to a main sequence O star with a "Wolf-Rayet clothing" than to the other members of the Wolf-Rayet family, which are rather highly evolved He-burning descendants of massive progenitors. [less ▲]

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See detailWR 134 line-profile variability : preliminary results of the 1994 campaign
Gosset, Eric ULiege; Vreux, Jean-Marie ULiege

in Vreux, J.-M.; Detal, Alain; Fraipont-Caro, Denise (Eds.) et al Wolf-Rayet stars in the framework of stellar evolution (1996)

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See detailA photometric classification of Wolf-Rayet stars
Vreux, Jean-Marie ULiege; Manfroid, Jean ULiege; Royer, P.

in Liege International Astrophysical Colloquia (1996)

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See detailLine-profile variability and mass-transfer in the early type binary BD+40° 4220
Vreux, Jean-Marie ULiege; Rauw, Grégor ULiege; Bohannan, B. et al

in Liege International Astrophysical Colloquia (1996)

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See detailWolf-Rayet stars in the framework of stellar evolution.
Vreux, Jean-Marie ULiege; Detal, Alain ULiege; Fraipont-Caro, D. et al

Book (1996)

The following topics were dealt with: evolution of massive stars - theory; observational characteristics of Wolf-Rayet stars and related objects; evidences for evolutionary links - transition objects ... [more ▼]

The following topics were dealt with: evolution of massive stars - theory; observational characteristics of Wolf-Rayet stars and related objects; evidences for evolutionary links - transition objects; analysis of the observations - the models and their results; massive stars in starburst. [less ▲]

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See detailA new orbital solution for the WNL binary system WR12
Rauw, Grégor ULiege; Vreux, Jean-Marie ULiege; Gosset, Eric ULiege et al

in Liege International Astrophysical Colloquia (1996)

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