Editing Light curve (section)

== Variable stars ==
{{main|Variable star}}
[[File:Delta Cephei lightcurve.jpg|thumb|Light curve of [[δ Cephei]] showing [[apparent magnitude|magnitude]] versus pulsation [[phase (waves)|phase]]]]

Graphs of the [[apparent magnitude]] of a variable star over time are commonly used to visualise and analyse their behaviour. Although the categorisation of variable star types is increasingly done from their spectral properties, the amplitudes, periods, and regularity of their brightness changes are still important factors. Some types such as [[Cepheid variable|Cepheids]] have extremely regular light curves with exactly the same period, amplitude, and shape in each cycle. Others such as [[Mira variable]]s have somewhat less regular light curves with large amplitudes of several magnitudes, while the [[semiregular variable]]s are less regular still and have smaller amplitudes.<ref name=gcvs/>

The shapes of variable star light curves give valuable information about the underlying physical processes producing the brightness changes. For eclipsing variables, the shape of the light curve indicates the degree of totality, the relative sizes of the stars, and their relative surface brightnesses.<ref name=russell/> It may also show the [[Eccentricity (astronomy)|eccentricity]] of the orbit and [[Ellipsoidal variable|distortions in the shape]] of the two stars.<ref name=kron/>  For pulsating stars, the amplitude or period of the pulsations can be related to the luminosity of the star, and the light curve shape can be an indicator of the pulsation mode.<ref name=wood/>

=== Supernovae ===
{{main|Supernova}}
[[File:Comparative supernova type light curves.png|thumb|Comparative [[supernova]] type light curves]]

Light curves from [[supernova]]e can be indicative of the type of supernova. Although supernova types are defined on the basis of their spectra, each has typical light curve shapes. [[Type I supernova]]e have light curves with a sharp [[Maxima and minima|maximum]] and gradually decline, while [[Type II supernova]]e have less sharp maxima. Light curves are helpful for classification of faint supernovae and for the determination of sub-types. For example, the type II-P (for plateau) have similar spectra to the type II-L (linear) but are distinguished by a light curve where the decline flattens out for several weeks or months before resuming its fade.<ref name=hyperphysics/>