Statistical analysis of asteroseismic indices and stellar parameters of TESS-observed delta Scuti stars

Abstract

Over the last few years stars have been at the center of the attention of the asteroseismology community thanks to the derivation of seismic indices connected to stellar parameters. The statistical analysis of the wealth of data offered by a large space survey such as the Transiting Exoplanet Survey Satellite (TESS), the identification of new stars, and the correlation between asteroseismic indices and stellar parameters in the resulting sample are therefore of utmost interest. The goal of our study is to analyze the statistical properties of stellar parameters and characterize the asteroseismic indices of stars observed in TESS cycle 4. We used TESS 2 min cadence photometric data and the corresponding Fourier transform to identify stars. The asteroseismic indices for these stars were determined using an empirical relation and a 2D autocorrelation method. We discovered 765 stars from the data obtained by the TESS mission, from Sectors 40 to 55, corresponding to cycle 4 and observed with a 2 min cadence. Of these stars, 179 stars have low-resolution spectral parameters from LAMOST. We first analyzed the relation between pulsation and stellar parameters from TESS observations and the distribution of stars with two different stellar parameters, TESS Input Catalog (TIC) and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), within the classical instability strip. Most of the stars lie within the instability strip and follow the period-luminosity relation of stars. Additionally, the majority of the stars exhibit pulsation properties consistent with those expected for stars, including periods falling within the typical range, amplitudes at the millimagnitude level, and fundamental parameters such as spectral type, effective temperature, log g, and luminosity that match the characteristics of stars. This confirms the reliability of the stars we have identified. We subsequently obtained the large frequency separation ($ max $, and $ Amax )$ for 179 stars with LAMOST parameters by using an empirical relation and a 2D autocorrelation method, and obtained the relations between these asteroseismic indices. These stars will provide significant support for a deeper study of the internal structure and evolution of stars.