Mira variable

A Mira variable is a type of star that experiences regular and large changes in brightness over periods ranging from about 80 to over 1,000 days. These stars are late in their life cycle and are giant or supergiant stars that pulsate—expanding and contracting—causing their brightness to vary noticeably. The name comes from "Mira," the first such star discovered, which appears as a very bright and then dim star in the night sky. Despite their dramatic brightness changes, Mira variables are stable over long periods and help astronomers study stellar evolution.