Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS - Discovery of two new GW Vir stars: TIC333432673 and TIC095332541

The TESS mission is revolutionizing the blossoming area of asteroseismology, particularly of pulsating white dwarfs and pre-white dwarfs, thus continuing the impulse of its predecessor, the Kepler mission. In this work, we present the observations from the extended TESS mission in both 120 s short-cadence and 20 s ultra-short-cadence mode of two pre-white dwarf stars showing hydrogen deficiency. We apply the tools of asteroseismology with the aim of deriving their structural parameters and seismological distances. We carried out a spectroscopic analysis and a spectral fitting of TIC333432673 and TIC095332541. We also processed and analyzed the high-precision TESS photometric light curves of the two target stars, and derived their oscillation frequencies. We performed an asteroseismological analysis of these stars on the basis of PG1159 evolutionary models that take into account the complete evolution of the progenitor stars. We searched for patterns of uniform period spacings in order to constrain the stellar mass of the stars, and employed the individual observed periods to search for a representative seismological model.Poster for TESS Science Conference