Interpretation of light curves of IP Peg in a model with shockless interaction between the gas stream and disk

We have analyzed light curves of the eclipsing cataclysmic variable IP Peg. A model with a shockless interaction between the gaseous stream and disk ( i.e., an elliptical disk with a "hot line") can describe the main character istic features of the light curve of the interacting close binary better th an a classical model with a "hot spot" at the outer boundary of a circular accretion disk. In particular, the hot-line model can reproduce the luminos ity increase observed at phases phi similar to 0.1-0.2 and phi similar to 0 .5-0.6, which is not possible in the standard hot-spot model. The advantage s of the hot-line model are particularly striking for the IR light curves o f IP Peg: the discrepancy chi (2) between the theoretical and observed ligh t curves is 49 for the model with a shockless interaction between the gaseo us stream and disk, and 2681 for the standard hot-spot model. (C) 2001 MAX "Nauka/Interperiodica".