Related papers: Fast Rotation vs. Metallicity
Rotation appears as a dominant effect in massive star evolution. It largely affects all the model outputs: inner structure, tracks, lifetimes, isochrones, surface compositions, blue to red supergiant ratios, etc. At lower metallicities, the…
Recent theoretical predictions for low metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and as such should retain most of their angular momentum.…
Star clusters are privileged laboratories for studying the evolution of massive stars (OB stars). One particularly interesting question concerns the phases, during which the classical Be stars occur, which unlike HAe/Be stars, are not…
This paper presents a detailed statistical determination of the equatorial rotation rates of classical Be stars. The rapid rotation of Be stars is likely to be linked to the ejection of gas that forms dense circumstellar disks. The physical…
Even though it is broadly accepted that single Be stars are rapidly rotating stars surrounded by a flat rotating circumstellar disk, there is still a debate about how fast these stars rotate and also about the mechanisms involved in the…
We report on the status of our spectropolarimetric observations of massive stars. During the last years, we have discovered magnetic fields in many objects of the upper main sequence, including Be stars, beta Cephei and Slowly Pulsating B…
We propose the Wind of Fast Rotating Massive Stars scenario to explain the origin of the abundance anomalies observed in globular clusters. We compute and present models of fast rotating stars with initial masses between 20 and 120 Msun for…
Angular momentum is a key property regulating star formation and evolution. However, the physics driving the distribution of the stellar rotation rates of early-type main-sequence stars is as yet poorly understood. Using our catalog of…
At low metallicity the B-type stars rotate faster than at higher metallicity, typically in the SMC. As a consequence, it was expected a larger number of fast rotators in the SMC than in the Galaxy, in particular more Be/Oe stars. With the…
New constraints on stellar models are provided by large surveys of massive stars, interferometric observations and asteroseismology. After a review of the main results so far obtained, we present new results from rotating models and discuss…
The rotation rates and magnetic activity of Sun-like and low-mass (< 1.4 Msun) main-sequence stars are known to decline with time, and there now exist several models for the evolution of rotation and activity. However, the role that…
To study the effects of metallicity and evolution on the appearance of the Be phenomenon in the B stars population, we observed several fields in the Large and Small Magellanic Clouds (LMC and SMC, respectively) which have different…
We present new results obtained with the VLT GIRAFFE for a large sample of B and Be stars belonging to the Magellanic Clouds, i.e. at low metallicity. First, we show the effects of the metallicity of the environment on their rotation…
Rotation has a number of important effects on the evolution of stars. Apart from structural changes because of the centrifugal force, turbulent mixing and meridional circulation caused by rotation can dramatically affect a star's chemical…
Using single star models including the effects of shellular rotation with and without magnetic fields, we show that massive stars at solar metallicity with initial masses lower than about 20-25 M$_\odot$ and with an initial rotation above…
The rotation rate of a star has important implications for the detectability, characterisation and stability of any planets that may be orbiting it. This chapter gives a brief overview of stellar rotation before describing the methods used…
Rapid rotation enhances the dynamo operating in stars, and thus also introducessignificantly stronger magnetic activity than is seen in slower rotators. Many young cool stars still have the rapid, primordial rotation rates induced by the…
(Abridged) Rotation has been shown to play a determinant role at very low metallicity, bringing heavy mass loss where almost none was expected. Is this still true when the metallicity strictly equals zero? The aim of our study is to get an…
The Large and Small Magellanic Clouds are priviledged environments to perform tests of theoretical predictions at low metallicity on rotational velocities and stellar evolution. According to theoretical predictions, the rotational…
Several studies have shown recently that at low metallicity B-type stars rotate faster than in environments of high metallicity. This is a typical case in the SMC. As a consequence, it is expected that a larger number of fast rotators is…