The loss of large amplitude pulsations at the end of AGB evolution

Abstract

Since 2013 we are performing with the Nancay Radio Telescope (NRT) a monitoring program of >100 Galactic disk OH/IR stars, having bright 1612-MHz OH maser emission. The variations of the maser emission are used to probe the underlying stellar variability. We wish to understand how the large-amplitude variations are lost during the AGB - post-AGB transition. The fading out of pulsations with steadily declining amplitudes seems to be a viable process.

2 pages, no figures, to appear in IAUS 343, Why Galaxies Care about AGB Stars, F. Kerschbaum, M. Groenewegen \& H. Olofsson, eds