Radial velocity monitoring of (candidate) hybrid A- and F-type stars from the Kepler mission

An ensemble of 50 candidate hybrid A/F-type stars from the Kepler mission was monitored during four years with the HERMES spectrograph attached to the Mercator telescope. From this survey, we obtained new radial velocities, new or improved atmospheric properties (Teff, log g, v sin i), and classified all our targets in terms of evidence for multiplicity, pulsation and/or fast rotation. An extension of 40 new candidate hybrid A- and F-type stars from the Kepler mission has been recently defined for a second survey to be performed under similar conditions. The new high-resolution spectra will be obtained with various small to medium-sized telescopes. For a number of newly detected stellar systems with good radial velocity coverage, we also computed much improved orbits by combining the radial velocities with the time delays obtained via the monitoring of the pulsation frequencies during the four years of Kepler photometry.