# High-resolution spectroscopy and abundance analysis of Delta Scuti stars near the Gamma Doradus instability strip

## TL;DR

This study provides a detailed spectroscopic analysis of 41 Delta Scuti stars near the Gamma Doradus instability strip, exploring their atmospheric parameters, chemical abundances, and pulsation characteristics to better understand their pulsation behavior.

## Contribution

It offers new spectroscopic data and comparative analysis of Delta Scuti, Gamma Doradus, and non-pulsating stars, highlighting chemical and physical differences relevant to stellar pulsation.

## Key findings

- Delta Scuti stars have spectral types A1-F5 and luminosity classes III-V.
- Pulsation period decreases with increasing effective temperature.
- No significant correlation between pulsation period, amplitude, and rotational velocity.

## Abstract

$\delta$ 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_{\rm 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 ($T_{\rm eff}$, $\log g$, $\xi$) 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 $T_{\rm eff}$ 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 $T_{\rm eff}$. No significant correlations were found between pulsation period, amplitude and $v \sin i$.