Determination of chemical abundances of HD 73574 and BD +19◦2045.

Abstract

The intermediate mass stars on the upper main sequence (MS) of the Hertzsprung Russell diagram (HRD) show interesting phenomena. These include chemical peculiarities, magnetic field variability, pulsations and rotation. The high resolution photometric data and low resolution ground-based spectroscopic data have been used in the past decades to characterise intermediate mass stars. The number of intermediate mass stars that have been fully characterised as chemically peculiar stars using high resolution ground-based spectroscopic data is still limited. This study increased the number of chemically peculiar stars in the general catalogue by using high resolution ground-based spectroscopic data. This data was used to determine fundamental atmospheric parameters and individual chemical abundances of HD 73574 and BD +19◦2045 to fully characterise the target stars. The spectral types of the targets were determined and their fundamental atmospheric parameters obtained by spectral synthesis. The detailed chemical abundance analysis for each target was also performed. The masses of HD 73574 and BD +19◦2045 were derived as 1.998 ± 0.1 M and 1.499 ± 0.1 M, respectively. The ages were found to be 665 ± 34 Myr for BD +19◦2045 and 702 ± 69 Myr for HD 73574. HD 73574 was classified as kA7hA8mK2 and BD +19◦2045 as F2 V. Therefore, HD 73574 is an Am star while BD +19◦2045 is a normal star. To estimate their evolutionary phases, all the targets were placed in the HRD. Based on spectral classification and the chemical abundance pattern of each target, HD 73574, previously treated as chemically normal A-type star, was reclassified as a chemically peculiar Am star (kA7hA8mK2) and BD +19◦2045 remained a chemically normal F-type star as previously classified.