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A Search for Random Cycle-to-Cycle Period Fluctuations in Five δ Scuti, SX Phoenicis, and RR Lyrae Variables

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John R. Percy

Kaushala Bandara

Pietro Cimino

Department of Astronomy and Astrophysics, University of Toronto, Toronto ON Canada M5S 3H4


Received March 29, 2007; revised June 13, 2007; accepted June 14, 2007


Random cycle-to-cycle period fluctuations in pulsating stars were first studied by Eddington and Plakidis in 1929, and have subsequently been found in almost all Mira stars, many RV Tauri stars, and a few Cepheids. They complicate the use of (O-C) diagrams for studying evolutionary period changes in these stars. We set out to study such fluctuations in four δ Scuti stars and SX Phoenicis stars; we added one RR Lyrae star for testing purposes. We discuss complications that arise in applying this method to short-period stars. Only one of the five stars—the SX Phoenicis star XX Cyg—showed statistically-significant fluctuations.

Link to Article on ADS

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