The discovery of rapid oscillations in the magnetic Ap stars HD69013 and HD96237

Abstract

We report the detection of short-period variations in the stars HD69013 and HD96237. These stars possess large overabundances of rare earth elements and global magnetic fields, thus belong to the class of chemically peculiar Ap stars of the main sequence. Pulsations were found from analysis of high time resolution spectra obtained with the European Southern Observatory (ESO) Very Large Telescope using a cross-correlation method for wide spectral bands, from lines belonging to rare earth elements and from the Hα core. Pulsation amplitudes reach more than 200ms-1 for some lines in HD69013 with a period of 11.4min and about 100ms-1 in HD96237 with periods near 13.6min. The pulsations have also been detected in photometric observations obtained at the South African Astronomical Observatory. © 2010 The Authors Monthly Notices of the Royal Astronomical Society © 2010 RAS.