Type Ia supernovae are a specific type of supernova that occur in binary star systems where one star is a white dwarf and the other is a companion star. When the white dwarf accretes matter from its companion star and reaches a certain mass limit, it undergoes a thermonuclear explosion, releasing a tremendous amount of energy and brightness. Type Ia supernovae are important astronomical events because they have a consistent peak luminosity, allowing them to be used as standard candles for measuring astronomical distances. These supernovae have been instrumental in determining the expansion rate of the universe and the discovery of dark energy.