Gray, David

Contact Email: dfgray@uwo.ca
Institute: University of Western Ontario
Subject Area: Stellar Atmospheres, Circumstellar Material
Waveband: Optical
Technique: Astero (Helio-) Seismology
Presentation: Oral Contribution: Thursday
Title: Betelgeuse: Observational Constraints on Giant-cell Convection
Abstract: Giant convection cells have been predicted and are generally expected to occur in the atmospheres of supergiant stars like Betelgeuse. But high resolution spectroscopic observations taken over several months at the Elginfield Observatory show spectral lines with remarkably stable shapes, especially considering the very significant changes the star shows in the central depths of its spectral lines and in its apparent magnitude. Either giant convection cells do not occur in the photosphere of Betelgeuse, or else they have very small velocities and/or contrast so that no spectroscopic signature is produced.