RZ Vul is an interesting RV Tauri star of the RVB subclass. The RV Tauri stars are highly evolved giant stars that vary by pulsating. The RVB stars are characterized by long supercycles where the mean magnitude drops by a magnitude or more while the star maintains its underlying pulsation. The RVA subclass only show the simpler pulsation behavior with nearly constant mean light. The pulsation periods of all RV Tauris are on the order of weeks or months, while the supercycles of the RVB subclass can be several years in length. As a result, their striking light curves show a mix of low amplitude pulsations superimposed on larger super cycles. The class prototype RV Tauri itself shows this behavior; another classic RVB is U Monocerotis. Interestingly, RZ Vul only started experiencing deep dips in light fairly recently, within the past two decades.
Prepared By: Matthew Templeton