Publications (18)
Hot horizontal branch stars in NGC 288 - effects of diffusion and stratification on their atmospheric parameters
S. Moehler, S. Dreizler, F. LeBlanc +5
NGC288 is a globular cluster with a well-developed blue horizontal branch covering the u-jump that indicates the onset of diffusion. It is therefore well suited to study the effect…
New angles on D-branes
J. C. Breckenridge, G. Michaud, R. C. Myers
A low-energy background field solution is presented which describes several D-membranes oriented at angles with respect to one another. The mass and charge densities for this confi…
The Effect of Diffusion on Pulsations of Stars on the Upper Main Sequence. delta Scuti and Metallic A Stars
S. Turcotte, J. Richer, G. Michaud +1
Recent dramatic improvements in the modeling of abundance evolution due to diffusion in A stars have been achieved with the help of monochromatic opacity tables from the OPAL group…
Radiative Accelerations in Stellar Evolution
G. Michaud, J. Richer
A brief review of various methods to calculate radiative accelerations for stellar evolution and an analysis of their limitations are followed by applications to Pop I and Pop II s…
The Effects of Mass Loss on the Evolution of Chemical Abundances in Fm Stars
M. Vick, G. Michaud
Self-consistent stellar models including all effects of atomic diffusion and radiative accelerations as well as mass loss are evolved from the pre main sequence for stars of 1.35-1…
A search for magnetic fields in cool sdB stars
G. Mathys, S. Hubrig, E. Mason +3
Hot cluster Horizontal Branch (HB) stars and field subdwarf B (sdB) stars are core helium burning stars that exhibit abundance anomalies that are believed to be due to atomic diffu…
Abundance anomalies in pre-main-sequence stars: Stellar evolution models with mass loss
M. Vick, G. Michaud, J. Richer +1
The effects of atomic diffusion on internal and surface abundances of A and F pre-main-sequence stars with mass loss are studied in order to determine at what age the effects mater…
Hermitian D-brane solutions
G. Michaud, R. C. Myers
A low-energy background field solution describing D-membrane configurations is constructed which is distinguished by the appearance of a Hermitian metric on the internal space. Thi…
Models of Metal Poor Stars with Gravitational Settling and Radiative Accelerations: I. Evolution and Abundance Anomalies
O. Richard, G. Michaud, J. Richer +3
Evolutionary models have been calculated for Pop II stars of 0.5 to 1.0 from the pre-main-sequence to the lower part of the giant branch. Rosseland opacities and radiative…
The stratified evolution of a cool star
G. Michaud, J. Richer, O. Richard
A low mass star usually experiences stratification and abundance anomalies during its evolution. A 0.95 solar mass star with a metallicity Z = 0.004 is followed from the main-seque…
The Gaia-ESO Survey: Evidence of atomic diffusion in M67?
C. Bertelli Motta, A. Pasquali, J. Richer +37
Investigating the chemical homogeneity of stars born from the same molecular cloud at virtually the same time is very important for our understanding of the chemical enrichment of…
Sirius A: turbulence or mass loss?
G. Michaud, J. Richer, M. Vick
Context. Abundance anomalies observed in a fraction of A and B stars of both Pop I and II are apparently related to internal particle transport. Aims. Using available constraints f…
Two-dimensional dilaton black holes
G. Michaud, R. C. Myers
The two-dimensional CGHS model provides an interesting toy-model for the study of black hole evaporation. For this model, a quantum effective action, which incorporates Hawking rad…
Horizontal Branch stars as AmFm/HgMn stars
G. Michaud, J. Richer
Recent observations and models for horizontal branch stars are briefly described and compared to models for AmFm stars. The limitations of those models are emphasized by a comparis…
CP and related phenomena in the context of Stellar Evolution
J. Braithwaite, T. Akgün, E. Alecian +13
We review the interaction in intermediate and high mass stars between their evolution and magnetic and chemical properties. We describe the theory of Ap-star `fossil' fields, befor…
Horizontal Branch evolution, metallicity and sdB stars
G. Michaud, J. Richer, O. Richard
Context. Abundance anomalies have been observed in field sdB stars and in nearly all Horizontal Branch (HB) stars of globular clusters with Teff > 11 000K whatever be the cluster m…
More D-brane bound states
J. C. Breckenridge, G. Michaud, R. C. Myers
The low-energy background field solutions corresponding to D-brane bound states which possess a difference in dimension of two are presented. These solutions are constructed using…
Models for Solar Abundance Stars with Gravitational Settling and Radiative Accelerations: Application to M67 and NGC188
G. Michaud, O. Richard, J. Richer +1
Evolutionary models taking into account radiative accelerations, thermal diffusion, and gravitational settling for 28 elements, including all those contributing to OPAL stellar opa…