Influence of Digital Noise on Interpretation of a Transit Light Curve

The algorithms often used for the interpretation of light curves, such as the frequently applied JKTEBOP algorithm, have limited accuracy, which causes rounding errors, and hence a non-physical contribution to the residuals (digital noise). The transit light curve of the binary HD 209458 is used as an example to demonstrate the need to take into account this digital noise. Improving the accuracy of lightcurve computations enables more reliable determination of whether the observed light curve is adequately described by a particular model, thanks to the elimination of the non-physical contribution to the residuals resulting from computational errors. A website where the algorithm developed can be obtained is given in the Conclusions.