2002A&A...386..249D

We report on time series photometry of hot sdB stars from the Hamburg Schmidt survey carried out at the Calar Alto 1.23m and 2.2m telescopes. Among 14 spectroscopically selected candidates we detected oscillations in the sdB star HS 0702+6043 with a period of 363s and an amplitude of 29mmag which is among the largest amplitude observed in sdBV stars. A second period of 382s with a significantly smaller amplitude (3.8mmag) might be present. Our NLTE model atmosphere analysis of the time-averaged optical spectra, obtained at the Calar Alto 3.5m telescope, indicates that HS 0702+6043 has T_eff=28400K and logg=5.35. This places the star at the cool end of the theoretical sdBV instability strip (EC14026 stars). Among the other thirteen sdB stars we confirmed the variablity of the previously discovered sdBV HS 0815+4243 and identified twelve stars to be stable, for which we give upper limits for light variations.