Is macroturbulent broadening in OB Supergiants related to pulsations?
✍ Scribed by S. Simón-Díaz; K. Uytterhoeven; A. Herrero; N. Castro; J. Puls; C. Aerts
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 106 KB
- Volume
- 331
- Category
- Article
- ISSN
- 0004-6337
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✦ Synopsis
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 (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)