Mixing of CNO-cycled matter in massive stars
@inproceedings{Przybilla2010MixingOC, title={Mixing of CNO-cycled matter in massive stars}, author={Norbert Przybilla and Markus Firnstein and M. Fernanda Nieva and Georges Meynet and A. Maeder Remeis Observatory BambergECAP and Mpa Garching and Geneva Observatory}, year={2010} }
Aims. We test predictions of evolution models on mixing of CNO-cycled products in massive stars from a fundamental perspective. Relative changes within the theoretical C:N:O abundance ratios and the buildup of helium are compared with observational results. Methods. A sample of well-studied Galactic massive stars is presented. High-quality optical spectra are carefully analysed using improved NLTE line-formation and comprehensive analysis strategies. The results are put in the context of the…
100 Citations
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References
SHOWING 1-10 OF 42 REFERENCES
Observational manifestations of early mixing in B- and O-type stars
- Physics
- 1996
The helium and nitrogen enrichment of the atmospheres of early B-type stars during the main sequence (MS) evolutionary phase is re-analysed. It is confirmed that the effect depends on both the aget…
Quantitative spectroscopy of Deneb
- Physics
- 2008
Context. Quantitative spectroscopy of luminous BA-type supergiants offers a high potential for modern astrophysics. Detailed studies allow the evolution of massive stars, galactochemical evolution,…
Presupernova Evolution of Rotating Massive Stars. II. Evolution of the Surface Properties
- Physics, Geology
- 2000
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…
Carbon abundances of early B-type stars in the solar vicinity. Non-LTE line-formation for C II/III/I
- Physics
- 2008
Context. Precise determinations of the chemical composition in early B-type stars constitute fundamental observational constraints on stellar and galactochemical evolution. Carbon, in particular, is…
The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
- Physics
- 2009
Aims. We have previously analysed the spectra of 135 early B-type stars in the Large Magellanic Cloud (LMC) and found several groups of stars that have chemical compositions that conflict with the…
Quantitative spectroscopy of ba-type supergiants
- Physics
- 2006
Luminous BA-type supergiants have enormous potential for modern astrophysics. They allow topics ranging from non-LTE physics and the evolution of massive stars to the chemical evolution of galaxies…
Helium and Carbon Abundances in Late-B and Early-A Supergiants
- Physics
- 2000
The abundances of carbon and helium were determined for representative late-B and early-A supergiants based on the Cl lines (9078, 9089, 9095, 9112) in the near-IR, Cll lines (4267, 6151), and the He…
Improving stellar parameter and abundance determinations of early B-type stars
- Physics, Geology
- 2009
In the past years we have made great efforts to reduce the sta- tistical and systematic uncertainties in stellar parameter and chemical abun- dance determinations of early B-type stars. Both the…
Nitrogen enrichment, boron depletion and magnetic fields in slowly-rotating B-type dwarfs
- Physics
- 2008
Evolutionary models for massive stars, accounting for rotational mixing effects, do not predict any core-processed material at the surface of B dwarfs with low rotational velocities. Contrary to…
Hydrogen and helium line formation in OB dwarfs and giants - A hybrid non-LTE approach
- Physics
- 2007
Aims. Hydrogen and helium line spectra are crucial diagnostic features for the quantitative analysis of OB stars. Hybrid non-LTE line-formation calculations for these elements have not been discussed…