The statistical aspects of the use of the Hipparcos photometric data in variability research have been described by van Leeuwen et al. (1997) and in Vol. 3 of ESA (1997). The distribution of gaps and the lengths of data stretches is far from optimal for periods between a few days and 40 to 70 days, and aliassing is often impossible to distinguish: the window functions resulting from the distribution of data were generally very poor. Statistical indicators of variability were, due to the relatively large number of observations per star, on the other hand quite reliable.
For all stars the period searching method of Stellingwerf (1978) was used. In many cases we also made use of the algorithm of Sterken (1977), which is based on a sine curve fit to the data, usually with more or less the same results. For the early type stars the search was made between 1d and 100d and extended to a few hundred days for the late type stars.
Because of the difficulty in defining a reliable quasi-period, we often present
a few periods resulting from the periodogram in order of decreasing
significance. In some cases, two or more actual periods can be present, like
this is the case for 
Sco and R40 (Sterken et al. 1997, 1998). With the most dominant period one can often obtain a
satisfactory phase diagram, which may give the wrong impression of being the
only "true'' quasi-period, with the remaining scatter only due to different
types of stochastic processes. Apparently significant periods are illustrated
with folded light curves, but this does not exclude other or alternative
periods being possible.
The stars are described in order of increasing HIP identifier. This identifier is then followed by one or more of the following catalogue numbers: HR/HD/HDE number, R (Radcliffe) number for the Magellanic Cloud objects (Feast et al. 1969), and if available the name given in the General Catalogue of Variable Stars and its extensions (Kholopov et al. 1985). Spectral types used in the text are those we considered the most reliable available in the literature, those in Fig. 1 (click here) to Fig. 3 (click here) are the ones presented in ESA 1997, except for HIP 67261, where the spectral type as given by ESA 1997 is very wrong (A7V i.s.o. G8Ia).