chris collister May 1, 2011:

Since a (mathematical) point is of dimension zero, the only other source of information about this source is contained in its radiation. Hence the conclusion is that the luminous intensity is varying sinusoidally. However, this is not going to be a true y=sin(kt) since you can't have a negative luminosity. Rather, there may be a sinusoidal ripple superimposed on a quasi-steady signal. Diminutive exoplanets are more often than not detected by the sinusoidal ripple in the light from sun around which they orbit.