Eight Phase-step δ Scuti Variables in TESS Data

Analysis of the previously classified delta Scuti variable star MW Camelopardalis using data from the Transiting Exoplanet Survey Satellite sparked a deeper inquiry due to unexpected patterns within the target’s observed − calculated (O − C) diagram. The shape could be seen as either a saw-toothed pattern or a set of steps. The pattern was found to be replicated in the O − C diagrams of seven additional targets: TIC 17931346, TIC 44845403, TIC 123580083, TIC 173503902, TIC 302394816, TIC 194944219m and TIC 396465600. The Q value for the targets, their position in the δ Scuti star Leavitt Law, and their location in the instability strip show these objects to be low-mass, fundamental mode pulsators. Seven of the eight stars fill the full range between the blue and red edges of the fundamental-mode instability strip.