RV Tauri (RV Tau) is a star in the constellation Taurus. It is a yellow supergiant and is the prototype of a class of pulsating variables known as RV Tauri variables.
RV Tau gives a better idea of the lives and deaths of stars like our Sun. It is likely a post-Asymptotic Giant Branch (AGB) star which is in the end stages of its life, just prior to the expulsion of planetary nebula and the eventual contraction into a white dwarf. Evolution models of Sun-like stars show it takes about 10 billion years for a 1 solar mass star to reach the Asymptotic Giant Branch.
RV Tau was discovered to be variable in 1905 by Lydia Ceraski, and by 1907 it was clear that it had an alternating minima. Over a period of 78.5 days its brightness can vary from magnitude +9.5 to +13.5. This change in luminosity is accompanied by a change in spectral type, being classified as G2 at its brightest and M2 at its dimmest. In addition to the fundamental period given, RV Tauri also exhibits slower variations in its mean luminosity over a period of 1100 days, during which time the maximum and minimum luminosity decreases. RV Tau is well placed for visual+CCD northern hemisphere observers during the northern winter months.
When RV Tau was assumed to have an absolute magnitude (M) of -3.65, it was estimated to be at a distance of about 1,607 parsecs (5,240 light-years). Since RV Tau is surrounded by a circumstellar disc, it has been estimated that RV Tau is at a distance of about 2,170 parsecs (7,100 light-years).