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arXiv · 1004.2524

Is macroturbulent broadening in OB Supergiants related to pulsations?

S. Simón-Díaz·K. Uytterhoeven·A. Herrero·N. Castro·J. Puls·C. Aerts
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Abstract

The spectrum of O and B Supergiants is known to be affected by an important extra line-broadening (usually called macroturbulence) that adds to stellar rotation. Recent analysis of high resolution spectra has shown that the interpretation of this line-broadening as a consequence of large-scale turbulent motions would imply highly super-sonic velocity fields, making this scenario quite improbable. Stellar oscillations have been proposed as a likely alternative explanation. We present first encouraging results of an observational project aimed at investigating the $macroturbulent$ broadening in O and B Supergiants, and its possible connection with spectroscopic variability phenomena and stellar oscillations: a) all the studied B Supergiants show line profile variations, quantified by means of the first (< v >) and third velocity (< v^3 >) moments of the lines, b) there is a strong correlation between the peak-to-peak amplitudes of the < v > and < v^3 > variability and the size of the extra-broadening.

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S. Simón-Díaz, K. Uytterhoeven, A. Herrero, N. Castro, J. Puls, C. Aerts. 2010-04-14. Is macroturbulent broadening in OB Supergiants related to pulsations?. https://doi.org/10.1002/asna.201011459

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