Sarkar, Mrinmoy ; Joshi, Santosh ; Dupret, Marc-Antoine ; Trust, Otto ; De Cat, Peter ; Semenko, Eugene ; Lampens, Patricia ; Goswami, Aruna ; Mkrtichian, David ; Karinkuzhi, Drisya ; Yakunin, Ilya ; Gupta, Archana

Poster presented at 43rd meeting of the Astronomical Society of India (ASI2025), Rourkela, India on 2025-02-15

Abstract: We present the results of an asteroseismic study of HD 118660 (TIC 171729860), a chemically peculiar (mild Am) star exhibiting delta scuti pulsations. It is based on the analysis of two sectors of time-series photometry from the space mission TESS ( Transiting Exoplanet Survey Satellite ) and seismic modelling. It yielded the detection of 15 and 16 frequencies for TESS sectors 23 and 50, respectively. The identified pulsation modes include four radial ( l = 0) and five dipolar ( l = 1) ones. The radial modes are overtones with order n ranging from 3 and 6. Such high values of n are theoretically not expected for stars with the effective temperature of HD 118660 ( Teff ≈ 7550 K) located near the red edge of the delta scuti instability strip. To estimate the asteroseismic parameters, we have generated a grid of stellar models assuming a solar metallicity ( Z = 0.014) and different values for the convective overshooting parameter (0.1 ≤ αov ≤ 0.3). We conclude that the analysis of the radial modes is insufficient to constrain αov and Z for delta scuti stars. The value for the equatorial velocity of HD 118660 derived from the seismic radius and the rotational frequency is consistent with values found in the literature.