Phenomenological Parameters of the Prototype Eclipsing Binaries Algol,   $\beta$ Lyrae and W UMa
  The phenomenological parameters of eclipsing binary stars, which are the prototypes of the EA, EB and EW systems are determined using the expert complex of computer programs, which realizes the NAV ("New Algol Variable") algorithm (Andronov 2010, 2012) and its possible modifications are discussed, as well as constrains for estimates of some physical parameters of the systems in a case of photometric observations only, such as the degree of eclipse, ratio of the mean surface brightnesses of the components. The half-duration of the eclipse is 0.0617(7), 0.1092(18) and 0.1015(7) for Algol, $\beta$ Lyrae and W UMa, respectively. The brightness ratio is 6.8$\pm$1.0, 4.9$\pm$1.0 and 1.15$\pm$0.13. These results show that the eclipses have distinct begin and end not only in EA (as generally assumed), but also in EB and EW - type systems as well. The algorithm may be applied to classification and study of the newly discovered (or poorly studied) eclipsing variables based on own observations or that obtained using photometric surveys. 
Mariia G. Tkachenko, Ivan L. Andronov, Lidia L. Chinarova
astro-ph.SR