Cepheid variable
Classical Cepheids (also known as Population I Cepheids, Type I Cepheids, or Delta Cephei variables) pulsate with very regular periods of the order of days to months.  Classical Cepheids are population I young variable stars which are 4–20 times more massive than the Sun, and up to 100,000 times more luminous. Cepheids are yellow supergiants of spectral class F6 – K2. When they pulsate, their radii change by ~25%. For the longer-period I Carinae this means millions of kilometers for a pulsation cycle.