Variable stars of small amplitude. II. Light variations of 7 supergiants of types B2 to G0 in the Geneva observatory photometric system.

A long series of observations of 7 Ia supergiants in the region of h and Persei were made, totalling 583 measurements in the magnitude and colour indices of the Geneva system. The observed stars were especially chosen so as to constitute an upper envelope of the supergiant branch between B2 and GO. All these stars are found to be variable with a peak-to-peak amplitude between 0WO35 and 0T065 in m . The semi-periodic character of this variation can be detected in almost all cases. Key words: variable stars - supergiants - multicolour photometry