HD 88366

S Carinae (HD 88366) is a variable star in the constellation Carina.

S Carinae is an M-type red giant with a mean apparent magnitude of +6.94. It is approximately 1,620 light years from Earth. It is classified as a Mira type variable star and its brightness varies between magnitude +4.5 and +10.0 with a period of 149.49 days. It has one of the earliest spectral types, and hence the hottest temperatures, of any Mira variable, and has a relatively short period for the class. The temperature of this pulsing star is highest at visual brightness maximum and lowest at visual brightness minimum.

S Carinae has exhausted its core hydrogen and expanded to become a red giant. It has also exhausted its core helium and evolved to the asymptotic giant branch, where it fuses hydrogen and helium in separate shells outside the core.