The Preliminary Results for Atmospheric Parameters of the Candidate Ap Stars HD 90763 and HD 92728

Abstract

Chemical peculiar Ap stars show overabundances ofsome metals, such as strontium, chromium, europium, praseodymium, andneodymium. The rotations of these stars are much slower than those of normalA-type stars. Another characteristic of Ap stars is that they have strongermagnetic fields compared to classical A-type stars. We have selected the A-typestars HD 90763 and HD 92728 to derive their atmospheric parameters. Both stars'high-resolution spectra were obtained using the Coude Echelle Spectrographmounted on the 1.5 m Russian-Turkish Telescope at the TÜBİTAK NationalObservatory, on the 23rd of February, 2017. The wavelength range ofthe spectra is from 3900 to 7900 Å. We followed the standard reductionprocedures for both stars and normalised the order covering the hydrogen betaprofile. We used ATLAS9 model atmospheres. The strontium 4215.519 Å line seenin the spectra of HD 90763 and the neodymium 5102.428Å line of HD 92728 were compared to the same lines of the normal A-typestar HD 187983. Sr line in HD 90763 and Nd line in HD 92728 are much strongerthan those of the normal A-type star. Thus, we suggest that HD 90763 and HD92728 may be chemically peculiar Ap star candidates.