Medium-term Variation in Times of Minimum of Algol-type Binaries: XZ And, RZ Cas, U Cep, TW Dra, U Sge

Volume 47 number 2 (2019)

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Geoff B. Chaplin

Hokkaido, Kamikawa-gun, Biei-cho, Aza-omura Okubo-kyosei, 071-0216, Japan;geoff@geoffgallery.net

Abstract

We use methods of singular spectrum analysis to examine the observed minus expected times of minimum of five Algol-type binaries looking for significant periodicities. All the stars examined show long “waves” of 20 to 50 years but only XZ And and RZ Cas appear to have significant periodicities.