December 10, 2004; revised April 19, 2005; accepted April 22, 2005
Abstract Z Tauri is a Mira variable with
observations in the AAVSO International Database dating back 85 years. Wavelet
analysis of the observations reveals a period decline of around 13% from 500
days to 442 days per cycle. In addition, flat minima suggest the possible
presence of an undetected companion.