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Last name: LEBRETON
First name: Y.
Astrophysics and Space Science, 316, pp. 61-73, http://dx.doi.org./10.1007/s10509-007-9663-9
We present recent work undertaken by the Evolution and Seismic Tools Activity (ESTA) team of the CoRoT Seismology Working Group. The new ESTA-Task 3 aims at testing, comparing and optimising stellar evolution codes which include microscopic diffusion of the chemical elements resulting from pressure, temperature and concentration gradients. The...
A solar model which includes the plausible presence of a mild mixing in the solar inner radiative zone is presented. The model takes into account the inhibition of turbulent motions. The properties of the model are compared to the standard model properties and to observational results: the turbulent diffusion mixing (TDM) improves the results...
A solar model which includes the plausible presence of a mild mixing in the solar inner radiative zone is presented. The model takes into account the inhibition of turbulent motions. The properties of the model are compared to the standard model properties and to observational results: the turbulent diffusion mixing (TDM) improves the results...
This paper examines the effects of axial-vector coupling constant g(A) changes on the outputs of solar-models (such as helium content, neutrino fluxes, and oscillations), using existing 'calibrated' solar models and assuming that the other inputs of the models are well-known. The results suggest that a very high value of g(A) (greater than...
The characterization of exoplanets relies on that of their host star. However, stellar evolution models cannot always be used to derive the mass and radius of individual stars, because many stellar internal parameters are poorly constrained. Here, we use the probability density functions (PDFs) of directly measured parameters to derive the...
The characterization of exoplanets relies on that of their host star. However, stellar evolution models cannot always be used to derive the mass and radius of individual stars, because many stellar internal parameters are poorly constrained. Here, we use the probability density functions (PDF) of directly measured parameters to derive the joint...
Context. Recently the triple-α reaction rate has been re-evaluated. In the temperature range, 107-108 K, with respect to the NACRE rate, the new rate is enhanced by up to 20 orders-magnitude. Aims: To validate this new rate, we investigate its consequences for the evolution of Cepheid models. Methods: The stellar evolutionary tracks are...
Detailed evolutionary models of the visual binary alpha Centauri, including pre main-sequence evolution, have been performed using the masses recently determined by Pourbaix et al. (1999). Models have been constructed using the CEFF equation of state, OPAL opacities, NACRE thermonuclear reaction rates and microscopic diffusion. A...
Astrophysics and Space Science, 316, pp. 219-229, http://dx.doi.org./10.1007/s10509-008-9803-x
Communications in Asteroseismology, 158, p. 277 (2009)
Astronomy and Astrophysics, 436, pp. 253-262, http://dx.doi.org./10.1051/0004-6361:20042075
International audience
Context. Chemical element transport processes are among the crucial physical processes needed for precise stellar modelling. Atomic diffusion by gravitational settling is usually taken into account, and is essential for helioseismic studies. On the other hand, radiative accelerations are rarely accounted for, act differently on the various...
Astronomy and Astrophysics, 1002, p. 3461 (2010)
Exoplanets' properties are directly linked to that of their host star. This is even more true in the case of transiting exoplanets, where the planetary radius cannot be derived if the stellar radius is unknown. Interferometry seems the best technique in this context, as it provides in a quasi-direct way and with exquisite precision the stellar...
We use absolute trigonometric parallaxes from the Hipparcos Catalogue to determine individual distances to members of the Hyades cluster, from which the 3-dimensional structure of the cluster can be derived. Inertially-referenced proper motions are used to rediscuss distance determinations based on convergent-point analyses. A combination of...
Context. The harvest of exoplanet discoveries has opened the area of exoplanet characterisation. But this cannot be achieved without a careful analysis of the host star parameters. Aims: The system of HD 219134 hosts two transiting exoplanets and at least two additional non-transiting exoplanets. We revisit the properties of this system using...
Astrophysics and Space Science, 316, pp. 1-4, http://dx.doi.org./10.1007/s10509-008-9771-1
Reliable stellar age estimates are fundamental for testing several problems in modern astrophysics, in particular since they set the time scales of Galactic dynamical and chemical evolution. In this study, we determine ages using only Gaia DR3 photometry and parallaxes, in combination with interstellar extinction maps, spectroscopic...