Astronomy and astrophysics vol:300 issue:1 pages:200-206
Six nights have been devoted to an intensive spectroscopic study (410 spectra in the H delta domain) of the star iota Her. Our data sampling is not suitable to undertake a period determination, but none of the previous published periods seem to be valid to represent the variations we observe. This is certainly due to a multiperiodic phenomenon. Thanks to the short exposure time, we strongly suspect a short time scale variability in addition to the longer periods. Therefore, two time scales would be involved, one being of the order of a day, the other being of the order of an hour, this latter having a 2K-amplitude around 0.8 km.s(-1), slightly varying. The short time scale is clearly detected at least in 5 nights, and concerns all the studied lines. The night-to-night variations (frequency, amplitude) measured are certainly due to the beat-modulation with the longer periods.