Variability and evolution in various classes of post-AGB stars

Abstract

We aim to compare properties of early-type post-asymptotic giant-branch (post-AGB) stars, including normal first-time B-type post-AGB stars, and extreme helium stars (EHes). Hipparcos photometry for 12 post-AGB stars and 7 EHe stars has been analyzed; 5 post-AGB stars are clearly variable. The Hipparcos data are not sufficiently sensitive to detect variability in any of the EHes.