A light curve is a graph that shows how the brightness of an astronomical object changes over time. It is commonly used in the study of stars, planets, and other celestial bodies to track variations in their light output. By analyzing light curves, astronomers can gain insights into the object's properties, such as its size, distance, and even the presence of exoplanets. Light curves are particularly important in the study of variable stars and transient events like supernovae. For example, the light curve of a supernova reveals its brightness over time, helping scientists understand the explosion's mechanics and the star's life cycle.