References of "Thoul, Anne"
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See detailCLÉS, Code Liégeois d'Évolution Stellaire
Scuflaire, Richard ULg; Théado, Sylvie; Montalban Iglesias, Josefa ULg et al

in Astrophysics & Space Science (2008), 316

CLÉS is an evolution code recently developed to produce stellar models meeting the specific requirements of studies in asteroseismology. It offers the users a lot of choices in the input physics they want ... [more ▼]

CLÉS is an evolution code recently developed to produce stellar models meeting the specific requirements of studies in asteroseismology. It offers the users a lot of choices in the input physics they want in their models and its versatility allows them to tailor the code to their needs and implement easily new features. We describe the features implemented in the current version of the code and the techniques used to solve the equations of stellar structure and evolution. A brief account is given of the use of the program and of a solar calibration realized with it. [less ▲]

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See detailThe Liège Oscillation code
Scuflaire, Richard ULg; Montalban Iglesias, Josefa ULg; Théado, S. et al

in Astrophysics & Space Science (2008), 316

The Liège Oscillation code can be used as a stand-alone program or as a library of subroutines that the user calls from a Fortran main program of his own to compute radial and nonradial adiabatic ... [more ▼]

The Liège Oscillation code can be used as a stand-alone program or as a library of subroutines that the user calls from a Fortran main program of his own to compute radial and nonradial adiabatic oscillations of stellar models. We describe the variables and the equations used by the program and the methods used to solve them. A brief account is given of the use and the output of the program. [less ▲]

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See detailAsteroseismology of beta Cephei stars: effects of the chemical composition
Thoul, Anne ULg

Conference (2007, August)

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See detailEffects of diffusion in β Cephei stars
Bourge, P*-O; Théado, S.; Thoul, Anne ULg

in Communications in Asteroseismology (2007), 150

We investigate the effects of the radiatively-driven diffusion of Fe, C, N and O in β Cephei stellar models.

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See detailMicroscopic Diffusion in Stellar Plasmas
Thoul, Anne ULg; Montalban Iglesias, Josefa ULg

in European Astronomical Society Publications Series (2007), 26

We review the basic equations describing the microscopic diffusion of elements in stars. We describe the two formalisms commonly used to describe a stellar plasma, i.e., the Chapman-Enskog method and the ... [more ▼]

We review the basic equations describing the microscopic diffusion of elements in stars. We describe the two formalisms commonly used to describe a stellar plasma, i.e., the Chapman-Enskog method and the Burgers equations. We point out the underlying assumptions about the physical state of the plasma itself. We briefly describe the different approximations which are often used to solve these equations, and discuss their validity. One of the major problems lies in the calculation of the collision integrals, and we discuss the different approaches to solving these integrals, emphasizing on their domain of validity. [less ▲]

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See detailAn asteroseismic study of the β cephei star θ ophiuchi : constraints on global stellar parameters and core overshooting
Briquet, Maryline ULg; Morel, Thierry ULg; Thoul, Anne ULg et al

in Monthly Notices of the Royal Astronomical Society (2007), 381(4), 1482-1488

We present a seismic study of the beta Cephei star theta Ophiuchi. Our analysis is based on the observation of one radial mode, one rotationally split l = 1 triplet and three components of a rotationally ... [more ▼]

We present a seismic study of the beta Cephei star theta Ophiuchi. Our analysis is based on the observation of one radial mode, one rotationally split l = 1 triplet and three components of a rotationally split l = 2 quintuplet for which the m values were well identified by spectroscopy. We identify the radial mode as fundamental, the triplet as p(1) and the quintuplet as g(1). Our non-local thermodynamic equilibrium abundance analysis results in a metallicity and CNO abundances in full agreement with the most recent updated solar values. With X epsilon [0.71, 0.7211] and Z epsilon [0.009, 0.015], and using the Asplund et al. mixture but with a Ne abundance about 0.3 dex larger, the matching of the three independent modes enables us to deduce constrained ranges for the mass (M = 8.2 +/- 0.3 M circle dot) and central hydrogen abundance (X-c = 0.38 +/- 0.02) of theta Oph and to prove the occurrence of core overshooting (alpha(ov) = 0.44 +/- 0.07). We also derive an equatorial rotation velocity of 29 +/- 7 km s(-1). Moreover, we show that the observed non-equidistance of the l = 1 triplet can be reproduced by the second-order effects of rotation. Finally, we show that the observed rotational splitting of two modes cannot rule out a rigid rotation model. [less ▲]

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See detailThe Seismology Programme of CoRoT
Michel, Eric; Baglin, A.; Auvergne, M. et al

in Proceedings of "The CoRoT Mission Pre-Launch Status - Stellar Seismology and Planet Finding (2006, November 01)

We introduce the main lines and specificities of the CoRoT Seismology Core Programme. The development and consolidation of this programme has been made in the framework of the CoRoT Seismology Working ... [more ▼]

We introduce the main lines and specificities of the CoRoT Seismology Core Programme. The development and consolidation of this programme has been made in the framework of the CoRoT Seismology Working Group. With a few illustrative examples, we show how CoRoT data will help to address various problems associated with present open questions of stellar structure and evolution. [less ▲]

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See detailBETADAT: A Beta Cephei Database
Thirion, Ambroise; Thoul, Anne ULg

in "Proceedings of "The CoRoT Mission Pre-Launch Status - Stellar Seismology and Planet Finding" (2006, November 01)

Not Available

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See detailInvited Review Talk - Microscopic diffusion in stellar plasmas
Thoul, Anne ULg

Conference (2006, November)

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See detailBetaDat: A beta Cephei database
Thoul, Anne ULg

Conference (2006, June)

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See detailPolytropes as simple models of beta Cephei stars
Godart, Mélanie ULg; Scuflaire, Richard ULg; Thoul, Anne ULg et al

in Communications in Asteroseismology (2006), 147

Beta Cephei stars have a simple structure: a convective core surrounded by a radiative envelope. It is therefore worth trying to describe beta Cephei stars with composite polytropes which are useful to ... [more ▼]

Beta Cephei stars have a simple structure: a convective core surrounded by a radiative envelope. It is therefore worth trying to describe beta Cephei stars with composite polytropes which are useful to retrieve structure parameters from frequency spectra. We show that the structure of beta Cephei models can relatively well be described with two-zone polytropic models. However this description is not convincing to depict oscillations of beta Cephei models. [less ▲]

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See detailRadiative forces and pulsation in beta Cephei stars
Bourge, P*-O; Alecian, G.; Thoul, Anne ULg et al

in Communications in Asteroseismology (2006), 147

Recently radiatively-driven diffusion in beta Cephei stars has been suggested as a possible explanation to account for excitation of the observed oscillation modes of the beta Cephei stars nu Eridani and ... [more ▼]

Recently radiatively-driven diffusion in beta Cephei stars has been suggested as a possible explanation to account for excitation of the observed oscillation modes of the beta Cephei stars nu Eridani and 12 Lacertae. Preliminary results (Bourge and Alecian 2006) show that microscopic diffusion of iron could indeed occur in a region situated just above the opacity bump of the iron group elements. This diffusion has little influence on the position of the star in the HR diagram and on the spectrum of low radial order eigenfrequencies. It does, however, increase the number of excited frequencies. We show here that the ratio between the number of p-modes to the number of g-modes could be used as a signature of this diffusion process. [less ▲]

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See detailAsteroseismology of the β Cephei star ν Eridani: massive exploration of standard and non-standard stellar models to fit the oscillation data
Ausseloos, M.; Scuflaire, Richard ULg; Thoul, Anne ULg et al

in Monthly Notices of the Royal Astronomical Society (2004), 355

We present the results of a detailed seismic modelling of the β Cephei star ν Eridani with the Liège evolution and pulsation codes. We selected four clearly detected, well-identified and independent ... [more ▼]

We present the results of a detailed seismic modelling of the β Cephei star ν Eridani with the Liège evolution and pulsation codes. We selected four clearly detected, well-identified and independent pulsation modes from the frequency spectrum obtained from a recent five-month multisite, multitechnique campaign, while previous modelling work only took into account three frequencies. We show by means of a massive exploration of the parameter space that no standard stellar model both matches and excites these four observed modes, in contrast to the conclusion reached when considering only three frequencies. Therefore, we have considered stellar models with different metal mixtures and different initial hydrogen abundance values. We show that an increase in the relative number fraction of iron throughout the whole star or a large decrease in the initial hydrogen abundance make the stellar models matching the four selected modes satisfy all observational constraints and we provide the general properties of the best such physical models. [less ▲]

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See detailSeismic Diagrams for beta Cephei stars; A database for COROT
Thoul, Anne ULg

Conference (2004, December)

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See detailAsteroseismology of the Beta Cephei star HD 129929. Effects of a change in the metal mixture
Thoul, Anne ULg; Scuflaire, Richard ULg; Ausseloos, M. et al

in Communications in Asteroseismology (2004), 144

We show that the constraints on the mass and on the rotation law in the envelope of the Beta Cephei star HD129929 are robust against a change in the metal mixture. The constraints on the metallicity and ... [more ▼]

We show that the constraints on the mass and on the rotation law in the envelope of the Beta Cephei star HD129929 are robust against a change in the metal mixture. The constraints on the metallicity and on the overshooting parameter, however, are dependent on the assumed metal mixture. [less ▲]

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See detailAsteroseismology of the beta Cep star HD 129929. I. Observations, oscillation frequencies and stellar parameters
Aerts, C.; Waelkens, C.; Daszynska-Daszkiewicz, J. et al

in Astronomy and Astrophysics (2004), 415

We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V beta Cep star HD 129929. The dataset has a time base of 21.2 years. The occurrence of a ... [more ▼]

We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V beta Cep star HD 129929. The dataset has a time base of 21.2 years. The occurrence of a beating phenomenon is evident from the data. We find evidence for the presence of at least six frequencies, among which we see components of two frequency multiplets with an average spacing of Ë 0.0121 c d[SUP]-1[/SUP] which points towards very slow rotation. This result is in agreement with new spectroscopic data of the star and also with previously taken UV spectra. We provide the amplitudes of the six frequencies in all seven photometric filters. The metal content of the star is Z=0.018± 0.004. All these observational results will be used to perform detailed seismic modelling of this massive star in a subsequent paper. Based on data gathered with the Swiss 0.7m telescope equipped with the photometer P7 of the Geneva Observatory and with the FEROS spectrograph attached to the ESO 2.2 m telescope, both situated at La Silla in Chile; the reduced photometric multicolour data are provided in Table 1, which is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/415/241 [less ▲]

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See detailAsteroseismology of the beta Cep star HD 129929. II. Seismic constraints on core overshooting, internal rotation and stellar parameters
Dupret, Marc-Antoine ULg; Thoul, Anne ULg; Scuflaire, Richard ULg et al

in Astronomy and Astrophysics (2004), 415

We perform a detailed seismic study of the beta Cep star HD 129929. Our analysis is based on the recent derivation of six pulsation frequencies. These frequencies are unambiguously identified from the ... [more ▼]

We perform a detailed seismic study of the beta Cep star HD 129929. Our analysis is based on the recent derivation of six pulsation frequencies. These frequencies are unambiguously identified from the seismic modelling and the photometric amplitudes to be the radial fundamental, the l=1, p[SUB]1[/SUB] triplet, two consecutive components of the l=2, g[SUB]1[/SUB] quintuplet. A non-adiabatic analysis allows us to constrain the metallicity of the star to Z \in [0.016, 0.022]. In addition, the fitting of three independent frequencies, two of which correspond to axisymmetric (m=0) modes, allows us to constrain the core overshooting parameter to alpha[SUB]ov[/SUB]=0.10 ± 0.05, as well as the other global parameters of the star. Finally, from the observation of the l=1 triplet and part of the l=2 quintuplet, we derive constraints on the internal rotation of this star. [less ▲]

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See detailDerivation of the rotational frequency of massive stars from seismic studies
Aerts, C.; Scuflaire, Richard ULg; Thoul, Anne ULg

in Stellar Rotation. 215 (2004)

In this contribution we review the current status of the determination of the rotational frequency in non-radially pulsating B stars, i.e. beta Cep stars and slowly pulsating B stars. Considerable ... [more ▼]

In this contribution we review the current status of the determination of the rotational frequency in non-radially pulsating B stars, i.e. beta Cep stars and slowly pulsating B stars. Considerable progress is currently being made in the understanding of the non-radial oscillations of main-sequence B Stars by means of high-temporal, high-spatial resolution spectroscopic time series. This has led to the detection of frequency multiplets, which are interpreted as rotationally splitted non-radial modes and which allow an accurate determination of the surface rotational frequency in some stars. We outline how our future goal, i.e. the derivation of the internal rotation frequency, can be achieved. [less ▲]

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See detailGeneva photometry of HD 129929 (Aerts+, 2004)
Aerts, C.; Waelkens, C.; Daszynska-Daszkiewicz, J. et al

in SIMBAD (2003), 341

We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V {beta} Cep star Hd 129929. The dataset has a time base of 21.2 years. The occurrence of a ... [more ▼]

We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V {beta} Cep star Hd 129929. The dataset has a time base of 21.2 years. The occurrence of a beating phenomenon is evident from the data. We find evidence for the presence of at least six frequencies, among which we see components of two frequency multiplets with an average spacing of ~0.0121c/d which points towards very slow rotation. This result is in agreement with new spectroscopic data of the star and also with previously taken UV spectra. We provide the amplitudes of the six frequencies in all seven photometric filters. The metal content of the star is Z=0.018+/-0.004. All these observational results will be used to perform detailed seismic modelling of this massive star in a subsequent paper. (1 data file). [less ▲]

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See detailSeismic Modelling of beta Cephei stars
Thoul, Anne ULg

Scientific conference (2003, October)

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