WH & TESS light curves of two eclipsing binaries

However, due to degeneracies between mass ratio and third-light contributions in purely photometric analyses, the derived mass ratios should be interpreted as lower limits, especially for J175200. The evolutionary states of these systems differ significantly. For J053525, a long-term period decrease is detected, with the orbital period derivative calculated as dP/dt=-1.99e-6day/yr.

In contrast, J175200 shows a period increase: dP/dt=1.93e-7day/yr. These contrasting period trends may be indicative of ongoing mass transfer; however, alternative explanations such as third-body effects cannot be ruled out. Nevertheless, the combination of their ultralow mass ratios, shallow contact configurations, and apparent period evolution highlights their unique value in testing mass ratio theories and the thermal relaxation oscillation hypothesis.