Observations of convection in A-type stars

Abstract

Convection and turbulence in stellar atmospheres have a significant effect on the emergent flux from A-type stars. The recent theoretical advancements in convection modelling have proved a challenge to the observers to obtain measurements with sufficient precision and accuracy to allow discrimination between the various predictions. A discussion of the current observational techniques used to evaluate the various convection theories is presented. These include filter photometry, spectrophotometry, hydrogen lines, and metal lines. The results from these techniques are given, along with the successes and limitations.Comment: 8 pages, 4 figures, Invited Lecture at IAU Symposium 224 "The A Star Puzzle", 7-13 July 2004, Poprad, Slovaki