Long-term Spectroscopic Monitoring of Cool Hypergiants HR 8752, IRC+10420, and 6 Cas near the Yellow Evolutionary Void
Abstract
We discuss the spectral variability of three white (A-type) hypergiants (Ia+) near the region of atmospheric dynamical instability in the upper H-R diagram, called the Yellow Evolutionary Void. The Void represents an obstacle for the fast blueward evolution of the most massive cool hypergiant stars. Optical and near-IR spectra observed between 1993 and 2011 with several high-resolution spectrographs, including the WHT-Utrecht Echelle Spectrograph, Mercator-HERMES, NOT-Sofin, and Keck-HIRES, are compared to investigate the wind-physics and -dynamics of the hypergiants.
- Publication:
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370 Years of Astronomy in Utrecht
- Pub Date:
- January 2013
- Bibcode:
- 2013ASPC..470..167L