High-resolution spectroscopy and spectropolarimetry of selected delta Sct pulsating variables

The combination of photometry, spectroscopy and spectropolarimetry of the chemically peculiar stars often aims to study the complex physical phenomena such as stellar pulsation, chemical inhomogeneity, magnetic field and their interplay with stellar atmosphere and circumstellar environment. The prime objective of this study is to determine the atmospheric parameters of a set of Am stars to understand their evolutionary status. Atmospheric abundances and basic parameters are determined using full spectrum fitting technique by comparing the high-resolution spectra to the synthetic spectra. To know the evolutionary status, we derive the effective temperature and luminosity from different methods and compare them with the literature. The location of these stars in the Hertzsprung-Russell diagram demonstrates that all the sample stars are evolved from the zero-age main sequence towards terminal-age main sequence and occupy the region of delta Sct instability strip. The abundance analysis shows that the light elements e.g. Ca and Sc are underabundant while iron peak elements such as Ba, Ce, etc. are overabundant and these chemical properties are typical for Am stars. The results obtained from the spectropolarimetric analysis of our studied stars show that the longitudinal magnetic field is negligible in all of them, which further support to their Am class of peculiarity.