The light is usually in a particular frequency interval or band. Light curves can be periodic, that is they repeat in a regular pattern. Examples are eclipsing binaries and cepheid variables. Light curves can also be aperiodic, that is they are irregular with no pattern. Examples include the light curve of a nova, a cataclysmic variable star, a supernova or other event. The study of the light curve, together with other observations, gives information about the physical process that produces it or constrains the physical theories about it.