delta Scuti and related stars: Analysis of the R00 Catalogue

We present a comprehensive analysis of the properties of the pulsating delt a Scuti and related variables based mainly on the content of the recently p ublished catalogue by Rodriguez et al. (2000a, hereafter R00). In particula r, the primary observational properties such as visual amplitude, period an d visual magnitude and the contributions from the Hipparcos, OGLE and MACHO long-term monitoring projects are examined. The membership of these variab les in open clusters and multiple systems is also analyzed, with special at tention given to the delta Scuti pulsators situated in eclipsing binary sys tems. The location of the delta Scuti variables in the H-R diagram is discu ssed on the basis of HIPPARCOS parallaxes and uvby beta photometry. New bor ders of the classical instability are presented. In particular, the propert ies of the delta Scuti pulsators with nonsolar surface abundances (SX Phe, lambda Boo, rho Pup, delta Del and classical Am stars subgroups) are examin ed. The Hipparcos parallaxes show that the available photometric uvby beta absolute magnitude calibrations by Crawford can be applied correctly to del ta Scuti variables rotating faster than v sin i similar to 100 km s(-1) wit h normal spectra. It is shown that systematic deviations exist for the phot ometrically determined absolute magnitudes, which correlate with v sin i an d deltam(1). The photometric calibrations are found to fit the lambda Boo s tars. but should not be used for the group of evolved metallic-line A stars . The related gamma Dor variables and the pre-main-sequence delta Scuti var iables are also discussed. Finally, the variables catalogued with periods l onger than 0(d).25 are examined on a star-by-star basis in order to assign them to the proper delta Scuti, RR Lyrae or gamma Dor class. A search for m assive, long-period delta Scuti stars similar to the triple-mode variable A C And is also carried out.