Photometric study of the dwarf nova VW Hydri.

Summary. Extensive photoelectric observations of VW Hyi have been carried out during minimum light and eruptions. In the minimum stage VW Hyi shows a periodically repeating hump (similar to that of U Gem) from which an orbital period of 0d07427 111 has been derived. No eclipses are present.-The two types of eruptions known previously for VW Hyi correspond to different physical processes: The short eruptions (lasting 4d) resemble again those of U Gem; the minimum hump disappears in bright phases. During the long eruptions (lasting I 7d) a pronounced peak- structured light curve has been observed with peri odicities of 0d0768 Significant colour variations with this period are also present. During one long maximum a separation of the repeating feature into two peaks is found. A first attempt has been made to interpret qualitatively the observed facts by an interaction between gas streams from the inner lagrangian point and ejected matter proceeding from the white dwarf component. Key words: dwarf novae eruptive variables - gas streams in close binary systems