NEW PULSATIONAL PROPERTIES OF 8 ANOMALOUS RR LYRAE VARIABLES

CCD photometry in the V band is presented for seven field RR Lyrae sta rs selected from a sample of eight variables; these, according to data collected in the literature, are expected to be ab-type pulsators, to have short periods (and hence high metallicity), and to be located at a high z from the Galactic plane. New periods and epochs are derived for them. The new periods are only slightly shorter than the values pu blished in the fourth edition of the General Catalogue of Variable Sta rs (GCVS4). In six cases our amplitude of the light Variation is signi ficantly smaller than that published in the GCVS4, and in at least thr ee cases the actual pulsation appears to be in the first harmonic rath er than in the fundamental mode. All the suggested c-type pulsators sh ow variations in the amplitude and/or quite scattered light curves. So me possible explanations are given. From a spectrophotometric analysis of the sample, only DL Com is confirmed to pulsate in the fundamental mode, to have a short period, and to be located at a relatively high z. However, a single object cannot be taken as evidence for a signific ant metal-rich population at a large distance from the Galactic plane.