Related papers: A constraint on the angular momentum evolution of …
We test the hypothesis of Berthet (1992) which foresees that Am stars become giant metallic A and F stars (defined by an enhanced value of the blanketing parameter Delta_m_2 of the Geneva photometry) when they evolve. If this hypothesis is…
The wind of an asymptotic-giant-branch stars is sufficiently strong that if it is slightly asymmetric, it can propel the star outside of the open cluster of its birth or significantly alter its trajectory through a globular cluster;…
Mass loss due to line-driven winds is central to our understanding of the evolution of massive stars. We extend the evolution models introduced in Paper I, where the mass loss recipe is based on the simultaneous calculation of the wind…
After a brief review of the observational evidences indicating how the populations of Be stars, red/blue supergiants, Wolf-Rayet stars vary as a function of metallicity, we discuss the implications of these observed trend for our…
[Abridged] One of the most outstanding problems related to numerical models of galaxy formation is the so-called ``angular momentum catastrophe''. We study the evolution of the angular momentum from z~0.6 to z=0 to further our understanding…
The rotation of horizontal branch stars places important constraints on angular momentum evolution in evolved stars and therefore rotational mixing on the giant branch. Prompted by new observations of rotation rates of horizontal branch…
Among the emission-line stars, the classical Be stars known for their extreme properties are remarkable. The Be stars are B-type main sequence stars that have displayed at least once in their life emission lines in their spectrum. Beyond…
(abridged) As the favoured progenitors of long-duration gamma-ray bursts, massive stars may represent our best signposts of individual objects in the early Universe, but special conditions seem required to make these bursters, which might…
We investigate a sample of 6 Herbig Ae/Be stars belonging to the Orion OB1 association, as well as 73 low mass objects, members of the $\sigma$ Orionis cluster, in order to explore the angular momentum evolution at early stages of…
We use TESS full-frame imaging data to investigate the angular momentum evolution of young stars in Orion Complex. We confirm recent findings that stars with rotation periods faster than 2 d are overwhelmingly binaries, with typical…
Transport of angular momentum has been a challenging topic within the stellar evolution community, even more since the recent asteroseismic surveys. All published studies on rotation using asteroseismic observations show a discrepancy…
Angular momentum evolution in low-mass stars is determined by initial conditions during star formation, stellar structure evolution, and the behaviour of stellar magnetic fields. Here we show that the empirical picture of angular momentum…
We present a novel theoretical tool to analyze the dynamical behaviour of a Be disk fed by non-constant decretion rates. It is mainly based on the computer code HDUST, a fully three-dimensional radiative transfer code that has been…
Be stars possess gaseous circumstellar decretion disks, which are well described using standard $\alpha$-disk theory. The Be star 28 CMa recently underwent a long outburst followed by a long period of quiescence, during which the disk…
We present the first part of a spectroscopic and polarimetric study on a sample of 58 Be stars that have been measured since 1998. The aim of the study is to understand the timescales of disk variability, formation and dissipation as a…
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…
As a star evolves off the Main Sequence, it endures major structural changes that are capable of determining the fate of the planets orbiting it. Throughout its evolution along the Red Giant Branch, the star increases its radius by two…
We investigate whether angular momentum transport due to unstable pulsation modes can play a significant role in the rotational evolution of massive stars. We find that these modes can redistribute appreciable angular momentum, and moreover…
The theory of radiation driven wind including stellar rotation is re-examined. After a suitable change of variables, a new equation for the mass loss rate is derived analytically. The solution of this equation remains within 1% confidence…
In this paper, we discuss some consequences of rotation and mass loss on the evolved stages of massive star evolution. The physical reasons of the time evolution of the surface velocity are explained, and then we show how the late-time…