Samarakoon, Theminda S.M.D. ; Adassuriya, Janaka ; De Cat, Peter ; Santosh Joshi, Santosh ; Jayaratne, Kalu Pathirannahelage Sarath Chandana ; Ganesh, Sashikiran

Poster presented at 4th BINA workshop, Calicut, India on 2025-11-04

Abstract: A high-resolution spectroscopic study of the δ Scuti type pulsating star SZ Lyn (HD 67390) was conducted to investigate its radial and non-radial pulsation modes. A total of 15 high-resolution spectra obtained by HERMES spectrograph in 2023 were analyzed using a combination of data reduction steps, including binary and phase calculation, spectral normalization, and heliocentric velocity correction. Three unblended metallic absorption lines, Ti (II) 4501.28 Å, Fe (I) 4957.59 Å, and Fe (II) 4508.29 Å, were examined using the FAMIAS. Frequencies were extracted using the Pixel-by-Pixel Fourier analysis method, and pulsation modes were identified through both the Fourier Parameter Fit (FPF) method and the moment method. The Ti (II) 4501.28 Å line revealed a frequency of 8.827 d-1, consistent with the photometric radial mode frequency of 8.296 d-1. The FPF method consistently identified the dominant pulsation mode of SZ Lyn as radial, with spherical degree l=0, and azimuthal order m=0. These results confirm that the primary pulsation of SZ Lyn is radial in nature. Radial velocity curves and radius variations over the pulsation phase further illustrate the star's behavior. This study demonstrates the possibility of high-resolution spectroscopy in probing stellar interiors and emphasizes the need for additional high-quality spectra and metallic lines, particularly those of heavier elements, to refine pulsation models and better constrain stellar parameters.