RV Tauri
The prototype of these variables, RV Tauri is a RVb type variable which exhibits brightness variations between magnitudes +9.8 and +13.3 with a formal period of 78.7 days. The brightest member of the class, R Scuti, is an RVa type, with an apparent magnitude varying from 4.6 to 8.9 and a formal period of 146.5 days. AC Herculis is an example of an RVa type variable.