New and improved rotational periods of magnetic CP stars from ASAS-3,
  KELT and MASCARA data
  Magnetic chemically peculiar (mCP) stars allow the investigation of such
diverse phenomena as atomic diffusion, magnetic fields and stellar rotation.
The aim of the present investigation is to enhance our knowledge of the
rotational properties of mCP stars by increasing the sample of objects with
accurately determined rotational periods. To this end, archival photometric
time-series data from the ASAS-3, KELT and MASCARA surveys were employed to
improve existing rotational period information and derive rotational periods
for mCP stars hitherto not known to be photometric variables. Our final sample
consists of 294 mCP stars, a considerable amount of which (more than 40%) are
presented here as photometric variables for the first time. In addition, we
identified 24 mCP star candidates that show light variability in agreement with
rotational modulation but lack spectroscopic confirmation. The rotational
period distribution of our sample agrees well with the literature.Most stars
are between 100Myr and 1Gyr old, with an apparent lack of very young stars. No
objects were found on the zero age main sequence; several stars seem to have
evolved to the subgiant stage, albeit well before the first dredge-up. We
identified four eclipsing binaries (HD 244391, HD 247441, HD 248784 and HD
252519), which potentially host an mCP star. This is of great interest because
mCP stars are very rarely found in close binary systems, particularly eclipsing
ones. Using archival spectra, we find strong evidence that the HD 252519 system
indeed harbours an mCP star component.
