A novel automated method for measuring spectral line indices of LAMOST-DR7 A-type stars

Stellar spectral line indices are key tools for studying stellar physical properties and evolutionary processes, playing a significant role in inferring important stellar attributes such as Teff, [Fe/H], and logg. This paper proposes an automated method for measuring stellar spectral line indices, specifically targeting LAMOST-DR7 A-type stellar spectra. The method involves several key steps: spectral preprocessing, continuum normalization, baseline correction, baseline fitting, spectral line fitting, and line index calculation, all aimed at achieving accurate spectral line index measurements. Traditional methods often encounter significant errors when dealing with complex spectral backgrounds. In contrast, the proposed method incorporates a series of optimizations and has been validated for robustness through Monte Carlo simulations. Our observational results indicate that this method is highly feasible from the comparisons to the line indices officially released by LAMOST and those in the Lick spectral library. Further testing with simulated data further demonstrates the reliability of this approach. This method provides a promising tool for future astronomical observations and stellar evolution studies and holds broad application potential. It not only helps improve the accuracy of research into stellar physical properties but also offers a practical technical approach for analyzing the composition and evolutionary patterns of stellar populations in galaxies.