Photometric Study of Three Short Period Variable Stars

We have obtained uvby - β photoelectric photometry with the 0.84 m telescope at the San Pedro Mártir Observatory, México, for the stars HD 115520, HD 220735 and HD 26738. The first two had been previously determined to be variables whereas the last one is being reported here as a new variable. With an extended time basis for the first two, we have determined their period of pulsation, which is found to be stable. Physical parameters are presented for the three stars.