High-resolution spectroscopy and abundance analysis of delta Scuti stars near the gamma Doradus instability strip

delta Scuti stars are remarkable objects for asteroseismology. In spite of decades of investigations, there are still important questions about these pulsating stars to be answered, such as their positions in log T-eff-log g diagram, or the dependence of the pulsation modes on atmospheric parameters and rotation. Therefore, we performed a detailed spectroscopic study of 41 delta Scuti stars. The selected objects are located near the gamma Doradus instability strip to make a reliable comparison between both types of variables. Spectral classification, stellar atmospheric parameters T-eff, log g, xi) and v sin i values were determined. The spectral types and luminosity classes of stars were found to be A1-F5 and III-V, respectively. The T-eff ranges from 6600 to 9400 K, whereas the obtained log g values are from 3.4 to 4.3. The v sin i values were found between 10 and 222 km s(-1). The derived chemical abundances of delta Scuti stars were compared to those of the non-pulsating stars and gamma Doradus variables. It turned out that both delta Scuti and gamma Doradus variables have similar abundance patterns, which are slightly different from the non-pulsating stars. These chemical differences can help us to understand why there are non-pulsating stars in classical instability strip. Effects of the obtained parameters on pulsation period and amplitude were examined. It appears that the pulsation period decreases with increasing T-eff. No significant correlations were found between pulsation period, amplitude and v sin i.