Zobrazeno 1 - 10
of 25
pro vyhledávání: '"Théado, Sylvie"'
Autor:
Vauclair, Sylvie, Théado, Sylvie
We have derived a new expression for the thermohaline mixing coefficient in stars, including the effects of radiative levitation and external turbulence, by solving Boussinesq equations in a quasi-incompressible fluid with a linear approximation. It
Externí odkaz:
http://arxiv.org/abs/1205.1329
Autor:
Pace, Giancarlo, Castro, Matthieu, Melendez, Jorge, Theado, Sylvie, Nascimento Jr, Jose-Dias do
Lithium abundances in open clusters are a very effective probe of mixing processes, and their study can help to understand the large depletion of lithium in the Sun. Due to its age and metallicity, the open cluster M67 is especially interesting on th
Externí odkaz:
http://arxiv.org/abs/1203.4440
Autor:
Théado, Sylvie, Vauclair, Sylvie
The early evolution of planetary systems is expected to depend on various periods of disk matter accretion onto the central star, which may include the accretion of metal-rich matter after the star settles on the main sequence. When this happens, the
Externí odkaz:
http://arxiv.org/abs/1109.4238
Atomic diffusion may lead to heavy element accumulation inside stars in certain specific layers. Iron accumulation in the Z-bump opacity region has been invoked by several authors to quantitatively account for abundance anomalies observed in some sta
Externí odkaz:
http://arxiv.org/abs/0908.1534
Autor:
Vauclair, Sylvie, Theado, Sylvie
Publikováno v:
Astron.Astrophys. 425 (2004) 179-185
Asteroseismology is found to be a excellent tool for detecting diffusion-induced helium gradients inside main-sequence A stars. Models have been computed for 1.6 and 2.0 M$_{\odot}$ stars with pure helium diffusion, at different ages, so that the hel
Externí odkaz:
http://arxiv.org/abs/astro-ph/0404266
Autor:
Theado, Sylvie, Vauclair, Sylvie
Publikováno v:
Astrophys.J. 587 (2003) 784-790
In the first paper of this series, we discussed analytically, in an approximate way, the mixing processes which occur in slowly rotating stars when the feed-back effects due to the diffusion-induced $\mu$-gradients are introduced in the computations.
Externí odkaz:
http://arxiv.org/abs/astro-ph/0301246
Autor:
Theado, Sylvie, Vauclair, Sylvie
Publikováno v:
Astrophys.J. 587 (2003) 795-805
In the two previous papers of this series, we have discussed the importance of t he $\mu$-gradients due to helium settling on rotation-induced mixing, first in a n approximate analytical way, second in a 2D numerical simulation. We have found that, f
Externí odkaz:
http://arxiv.org/abs/astro-ph/0301203
Autor:
Vauclair, Sylvie, Theado, Sylvie
Publikováno v:
Astrophys.J. 587 (2003) 777-783
In the presence of rotation-induced mixing, element diffusion still occurs in stellar radiative zones, although at a slower rate than in the case of a complete stability of the stellar gas. As a consequence, helium settling leads to vertical $\displa
Externí odkaz:
http://arxiv.org/abs/astro-ph/0301202
Autor:
Theado, Sylvie, Vauclair, Sylvie
The lithium plateau observed in halo stars has long appeared as a paradox in the general context of the lithium abundance behavior in stellar outer layers. First, the plateau is flat, second, the lithium abundance dispersion is extremely small. This
Externí odkaz:
http://arxiv.org/abs/astro-ph/0106080
The application to main-sequence stars of the rotation-induced mixing theory in the presence of mu-gradients leads to partial mixing in the lithium destruction region, not visible in the atmosphere. The induced lithium depletion becomes visible in th
Externí odkaz:
http://arxiv.org/abs/astro-ph/0002353