Related papers: Polarization from Rapidly Rotating Massive Stars
(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…
Massive stars exhibit a variety of instabilities, many of which are poorly understood. We explore instabilities induced by centrifugal forces and angular momentum transport in massive rotating stars. First, we derive and numerically solve…
Context. Binary evolution can result in fast-rotating stars, predicted to be observable as Be stars, through accretion of angular momentum during mass-transfer phases. Despite numerous observational evidence pointing to this possibly being…
We report on the detection of four rotating massive disks in two regions of high-mass star formation. The disks are perpendicular to known bipolar outflows and turn out to be unstable but long lived. We infer that accretion onto the…
Classical Be stars, the "e" standing for the presence of spectroscopic line emission, are main sequence stars of spectral type B that are able to form a gaseous disk in Keplerian motion from star-ejected matter. The main driver of this…
This article first reviews the basic physics of rotating stars and their evolution. We examine in particular the changes of the mechanical and thermal equilibrium of rotating stars. An important (predicted and observed) effect is that…
Classical Be stars are an enigmatic subclass of rapidly rotating hot stars characterized by dense equatorial disks of gas that have been inferred to orbit with Keplerian velocities. Although these disks seem to be ejected from the star and…
Binary stars produce an array of dramatic astrophysical phenomena. They allow us to probe stellar structure, nuclear physics, and gravitational wave physics. They also produce the powerful supernovae that allow us to measure the scale of…
Fast-rotating Wolf-Rayet (WR) stars are potential progenitors of long gamma-ray bursts, but observational verification is challenging. Spectral lines from their expanding stellar wind obscure accurate rotational velocity measurements.…
Differential rotation is central to a great many mysteries in stars and planets. In Part I we predicted the order of magnitude and scaling of the differential rotation in both hydrodynamic and magnetohydrodynamic convection zones. Our…
The Be star phenomenon is related to fast rotation, although the cause of this fast rotation is not yet clearly established. The basic effects of fast rotation on the stellar structure are reviewed: oblateness, mixing, anisotropic winds.…
We investigate how rapid stellar rotation commonly seen in A/F stars can influence planet habitability. Specifically, we model how rapid rotation influences a planet's irradiation and determine the location of the habitable zone for stars…
The tidal interaction of a Be star with a binary companion forms two spiral arms that cause orbital modulation of the Be disc structure. The aim of this work is to identify observables in which this modulation is apparent. The structure of…
Rotation can have severe consequences for the evolution of massive stars. It is now considered as one of the main parameters, alongside mass and metallicity that determine the final fate of single stars. In massive, fast rotating stars…
We study the effect of rotation on the excitation of internal oscillation modes of a star by the external gravitational potential of its companion. Unlike the nonrotating case, there are difficulties with the usual mode decomposition for…
I will show that Be stars are, without exception, a class of rapidly rotating stars, which are in the majority of cases pulsating stars as well, while none of them does possess a large scale (i.e. with significant dipolar contribution)…
Context. Stars experience rapid contraction or expansion at different phases of their evolution. Modelling the angular momentum and chemical elements transport occurring during these phases remains an unsolved problem. Aims. We study a…
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…
The main effect of axial rotation on the evolution of massive PopIII stars is to trigger internal mixing processes which allow stars to produce significant amounts of primary nitrogen 14 and carbon 13. Very metal poor massive stars produce…
The initial distribution of rotational velocities of stars is still poorly known, and how the stellar spin evolves from birth to the various end points of stellar evolution is an actively debated topic. Binary interactions are often invoked…