light curve

A light curve is the shape of the graph of a changing intensity of light (or other electromagnetic radiation) over the course of a transient (e.g., supernova, transit, gravitational microlensing). Such curves of a transient taken at specific wavelengths or passbands very often differ. Study of these curves and their differences-by-wavelength reveal information about the event and the object(s). In supernova study, the light curves of specific spectral lines reveal the presence of particular elements and isotopes in the supernova remnant, and any that are highly radioactive reveal recent synthesis, often as recent as the supernova itself. In extra-solar planet study, the light curve of the star can reveal the planet's presence (transit method), and study of such light curves at various wavelengths and bands reveal information about the planet's atmosphere's depth, constituents and structure.