Variations of the radio source OJ 287 at optical wavelengths.

Accurate photoelectric observations of the radio source OJ 287 and a standard star during 1972 March indicate the possible presence of a periodic component with a period of 39.2 min and an amplitude of 0.0065 mag. Examination of the light from OJ 287 for discrete frequency components and broad-band noise over a range of frequencies from 1.0 x 10- to 1.2 x 1 0 Hz does not reveal any peak in the power spectrum to our levels of sensitivity. The light curve obtained from the available photographic plates, dating from 1894 to the present, exhibits four bursts with timescales of several months. A slowly varying component rising and falling over a period of 2 years can be seen in the 1971 outburst. Similarities between OJ 287 and BL Lac are discussed. Subject headings: radio sources - variable stars