Major Traumas

Smith, Shauna L.

doi:10.1007/978-1-4899-6437-3_16

Cited by 16 publications

(24 citation statements)

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“…Point (ii) above is also the reason why late we stars are observed only in metal rich regions, while only early we stars are observed in metal poor zones (Smith & Maeder 1991). 3. Effects of rotation Fig.…”

Section: Effects Of Metallicity On the Stellar Yieldsmentioning

confidence: 76%

Chemical enrichment from Wolf-Rayet stellar winds

Meynet

1999

Symp. - Int. Astron. Union

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Abstract. Stellar winds contribute together with supernovae explosions to the chemical enrichment of the interstellar medium. We recall how the metallicity dependence of the stellar winds implies a metallicity dependence of the stellar yields. We show that an increase of the initial angular velocity has different effects than an increase of the mass loss rates. Wolf-Rayet stars appear as important sources of 19F and 26 AI. They are the favoured candidates for the 22Ne anomaly observed in the Galactic cosmic ray sources. They may also have injected into the proto-solar nebula short-lived radionuclides as 26 AI, 36 Cl, 41 Ca, 107Pd and 205Pb.

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Section: Effects Of Metallicity On the Stellar Yieldsmentioning

confidence: 76%

Chemical enrichment from Wolf-Rayet stellar winds

Meynet

1999

Symp. - Int. Astron. Union

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“…The question of a Z-dependence of mass-loss in WR stars remains open. There is a clear distinction amongst spectral subtypes in galaxies of differing metal content, which has been qualitatively explained from evolutionary and spectroscopic models (Smith & Maeder 1991;Crowther 2000). LMC WN stars (Crowther & Smith 1997;Hamann & Koesterke 2000) show negligible spectroscopic difference from Galactic counterparts.…”

Section: Wolf-rayet Starsmentioning

confidence: 90%

Stellar Winds from Massive Stars

Crowther¹

2001

Astrophysics and Space Science Library

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We review the various techniques through which wind properties of massive stars -O stars, AB supergiants, Luminous Blue Variables (LBVs), Wolf-Rayet (WR) stars and cool supergiants -are derived. The wind momentum-luminosity relation (e.g. Kudritzki et al. 1999) provides a method of predicting mass-loss rates of O stars and blue supergiants which is superior to previous parameterizations. Assuming the theoretical Z 0.5 metallicity dependence, Magellanic Cloud O star mass-loss rates are typically matched to within a factor of two for various calibrations. Stellar winds from LBVs are typically denser and slower than equivalent B supergiants, with exceptional mass-loss rates during giant eruptionsṀ = 10 −3 . . . 10 −1 M⊙ yr −1 (Drissen et al. 2001). Recent mass-loss rates for Galactic WR stars indicate a downward revision of 2-4 relative to previous calibrations due to clumping (e.g. Schmutz 1997), although evidence for a metallicity dependence remains inconclusive (Crowther 2000). Mass-loss properties of luminous (≥ 10 5 L⊙) yellow and red supergiants from alternative techniques remain highly contradictory. Recent Galactic and LMC results for RSG reveal a large scatter such that typical mass-loss rates lie in the range 10 −6 . . . 10 −4 M⊙ yr −1 , with a few cases exhibiting ∼ 10 −3 M⊙ yr −1 .

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“…However, conflicting results may result if limited model atoms are used, or if trace elements are neglected, such that Gräfener et al (1998) obtained C/He=0.32 by number (40% by mass) for HD 32125 (WC4), in contrast with the recent determination of C/He=0.13 by number (25% by mass) from Crowther et al (2002a). Carbon abundances in Galactic and LMC WC stars span a similar range, 0.1 ≤ C/He ≤ 0.4, such that spectral types are not determined by carbon abundances, in conflict with predictions by Smith & Maeder (1991). Hamann et al (these proc.…”

Section: Wc Propertiesmentioning

confidence: 90%

Stellar parameters of Wolf-Rayet stars from far-UV to mid-IR observations

Crowther¹

2003

Symp. - Int. Astron. Union

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Abstract. Recent results for Galactic and Magellanic Cloud Wolf-Rayet stars are summarised based on line blanketed, clumped model atmospheres together with UV, optical and IR spectroscopy. The trend towards earlier WN and WC spectral types with decreasing metallicity is explained via the sensitivity of classification diagnostics to abundance/wind density, such that WR mass-loss rates are metallicity dependent. Pre-supernovae masses for WC stars are determined, in reasonable agreement with CO-cores of recent Type-Ic SN.

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Major Traumas

Cited by 16 publications

References 0 publications

Chemical enrichment from Wolf-Rayet stellar winds

Chemical enrichment from Wolf-Rayet stellar winds

Stellar Winds from Massive Stars

Stellar parameters of Wolf-Rayet stars from far-UV to mid-IR observations

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