Detection of pulsations in three subdwarf B stars

We report the detection of short period oscillations in the sdB stars B8081 5+4243, HS2149+0847 and HS 2201+2610 from time-series photometry made at th e Nordic Optical Telescope (NOT) from a sample of 31 candidates. Hence thes e three hot subdwarfs are new members of the EC 14026 class of pulsating sd B stars. One short period is detected for HS 0815+4243 (P similar to 126 s; A similar to 7 mma) and two short periods are seen for HS 2149+0847 (P sim ilar to 142, 159 s; A similar to 11, 7 mma), whereas the single oscillation detected for HS 2201+2610 has a considerably longer period (P similar to 3 50 s; A similar to 11 mma). Our NLTE model atmosphere analysis of the time- averaged optical spectra indicate that HS 0815+4243 has T-eff = 33 700 K an d log g = 5.95, HS 2149+0847 has T-eff = 35 600 K and log g = 5.9, and HS 2 201+2610 has T-eff = 29 300 K and log g = 5.4. This places the former two a t the hot end and the latter at the cool end of the theoretical sdBV instab ility strip.