相关论文: Numerical Tests of Rotational Mixing in Massive St…
BONNFIRES, a new generation of population synthesis code, can calculate nuclear reaction, various mixing processes and binary interaction in a timely fashion. We use this new population synthesis code to study the interplay between binary…
Rotational mixing in massive stars is a widely applied concept, with far reaching consequences for stellar evolution. Nitrogen surface abundances for a large and homogeneous sample of massive B-type stars in the LMC were obtained by the…
Context. Light elements and nitrogen surface abundances together can constrain the mixing efficiencies in massive stars on the main sequence, because moderate mixing at the surface leads to a depletion of light elements but only later to an…
Aims: Past observations of fast-rotating massive stars exhibiting normal nitrogen abundances at their surface have raised questions about the rotational mixing paradigm. We revisit this question thanks to a spectroscopic analysis of a…
(Abridged) New boron abundances for seven main-sequence B-type stars are determined from HST STIS spectroscopy around the BIII 2066A line. Boron abundances provide a unique and critical test of stellar evolution models that include…
Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution…
One of the main uncertainties in evolutionary calculations of massive stars is the efficiency of internal mixing. It changes the chemical profile inside the star and can therefore affect the structure and further evolution. We demonstrate…
Aims: Recent observations have challenged our understanding of rotational mixing in massive stars by revealing a population of fast-rotating objects with apparently normal surface nitrogen abundances. However, several questions have arisen…
Models of rotating single stars can successfully account for a wide variety of observed stellar phenomena, such as the surface enhancements of N and He. However, recent observations have questioned the idea that rotational mixing is the…
The evolution and fate of massive stars are thought to be affected by rotationally induced internal mixing. The surface boron abundance is a sensitive tracer of this in early B-type main sequence stars. We test current stellar evolution…
The treatment of chemical mixing in the radiative envelopes of intermediate-mass stars has hardly been calibrated so far. Recent asteroseismic studies demonstrated that a constant diffusion coefficient in the radiative envelope is not able…
The rotation of stars has many interesting and important consequences for the photometric and chemical evolution of galaxies. Many of the predictions of models of stellar rotation are now compared with observations of surface abundances and…
Context: Internal chemical mixing in intermediate- and high-mass stars represents an immense uncertainty in stellar evolution models.In addition to extending the main-sequence lifetime, chemical mixing also appreciably increases the mass of…
The influence of rotational mixing on the evolution and asteroseismic properties of solar-type stars is studied. Rotational mixing changes the global properties of a solar-type star with a significant increase of the effective temperature…
We investigate the evolution of the surface properties of models for rotating massive stars, i.e., their luminosities, effective temperatures, surface rotational velocities, and surface abundances of all isotopes, from the zero age main…
Massive star evolution remains only partly constrained. In particular, the exact role of rotation has been questioned by puzzling properties of OB stars in the Magellanic Clouds. Our goal is to study the relation between surface chemical…
When modelling stars with masses larger than 1.2Msun with no observed chemical peculiarity, atomic diffusion is often neglected because, on its own, it causes unrealistic surface abundances compared with those observed. The reality is that…
Rotation has become an important element in evolutionary models of massive stars, specifically via the prediction of rotational mixing. Here, we study a sample of stars, including rapid rotators, to constrain such models and use nitrogen…
Rotational mixing in massive main sequence stars is predicted to monotonically increase their surface nitrogen abundance with time. We use this effect to design a method for constraining the age and the inclination angle of massive main…
We describe the main-sequence evolution of a rotating 9 $M_\odot$ star. Its interior rotation profile is determined by the redistribution of angular momentum through the meridian circulation and through the shear turbulence generated by the…