SIMBAD references

Series of spectrograms and a limited number of photometric measurements of selected early-type stars have been used to search in the measured radial velocities and light curves for stellar pulsations with timescales of a few hours. For these stars, located in the HR diagram between the β Cep and the δ Scu stars and designed sometimes as Maia variables, the presence of pulsations is claimed to be a common property. In our sample we found no hints for a general existence of such pulsations. RV-variations with the expected short-term scale could be observed for only two of the program stars, γ UMi and γ CrB. The variations are highly irregular in amplitude and frequency. On the other hand, for both stars a typical mean timescale of the RV-variation of about 2.4hr has been found which gives some hints to possibly common physical causes of short-term variations of stars in this part of the HR diagram. The RV-variation of γ CrB in the years 1992/93 could be attributed to a rotational splitting of nonradial pulsations.