Confirming Variability in TESS Candidate DA White Dwarfs

ZZ Ceti white dwarfs change in luminosity due to waves of material that travel across the surface and through the interior of the star. Two white dwarfs identified by data from NASA’s Transiting Exoplanet Survey Satellite (TESS) as potential ZZ Cetis were observed using the telescope at Texas A&M Commerce and the SARA Kitt Peak telescope. After reducing the images and calculating the lightcurves of each target using multiple aperture photometry, a Fourier transform was used to identify the component frequencies. Variability was confirmed in one white dwarf, but the observed period (>6 hr) conflicts with known ZZ Ceti pulsations and may be a result of rapid rotation. The other white dwarf was observed to vary on a ~120 s period on the first night but not subsequent nights. Further time-series observations will be required to confirm findings.