RADIO-SOURCES IN THE VICINITY OF FLARE STARS

During simultaneous observations of four flare stars between the Steph anion Observatory (optical - U or B band) and Effelsberg (radio - 2695 MHz), several strong optical flares were detected without counterpart at radio wavelengths (at a level >60 mJy). This result suggests that the optical and radio flares are produced by different mechanisms. The radio flares reported in the past from these and other flare stars ma y be related to the recently detected phenomenon of short time optical variability. Some reported radio flares could also be attributed to t he existence of other radio sources which happen to be in the primary beam of the radio telescopes. Mapping the area around seven well known flare stars has revealed in fact the existence of several strong radi o sources in their vicinity. Most of these sources appear to be extrag alactic.