The behaviour of chemical elements in 62 Am star candidates

Abstract

In this paper, we present the results of a spectroscopic campaign devoted to ascertain the actual nature of a sample of 155 objects reported as uncertain peculiar stars in the General catalogue of Ap, Am, and HgMn stars. Spectroscopic observations have been obtained with Catania Astrophysical Observatory Spectropolarimeter. We derive for all the objects that appear to be single stars, effective temperature, gravity, rotational and radial velocities, and chemical abundances by spectral synthesis method, then by using an abundance-based criterion we selected 62 Am star candidates. Further, by using the positions of these stars within the theoretical instability strips for δ Sct and γ Dor in the Hertzsprung-Russell diagram, we selected 46 out of 62 candidates to be possible pulsating stars, in particular 42 are candidates δ Sct and four candidates hybrid stars.