HD 97394: a magnetic Ap star with high cerium overabundance

Abstract

We report a spectroscopic analysis of the chemically peculiar Ap star HD 97394. The stellar spectrum is rich in lines of rare earth elements with large overabundances, especially cerium, gadolinium and europium. Enhancement of the abundances of these rare earths shows this star to be one of the most peculiar stars. Very large overabundances were found for lines of Ce iii and Eu iii. Abundances obtained from second ionization lines of Nd, Ce and Eu are about 2 dex higher than for those of the first ionization. From partially split Zeeman components of the Fe ii 6149.258 Å line and from synthetic modelling, a global magnetic field of 3.1 kG was measured. We tested for pulsation of the star with high time resolution spectroscopy obtained with the ESO Very Large Telescope. We place an upper limit to any pulsation amplitude of 30–40 m s−1 for individual lines of rare earth elements, of 10–20 m s−1 for the combination of several lines, and of 6–10 m s−1 for cross-correlation over large spectral bands.