WD 1054-226 revisited: A stable transiting debris system

Context . A growing number of white dwarfs (WDs) exhibit one or more signs of remnant planetary systems, including transits, infrared excesses, and atmospheric metal pollution. WD 1054-226 stands out for its unique, highly structured, and persistent photometric variability. Aims . We investigate the long-term stability and nature of the periodic signals observed in WD 1054-226 to better understand the origin and evolution of its transiting material. Methods . We analysed all available TESS light curves from Sectors 9, 36, 63, and 90 using Lomb–Scargle, box-least-squares, and Gaussian process periodogram analyses. We complemented them with multi-band, high-cadence ground-based photometry from LCOGT, MuSCAT2, ALFOSC, and ProEM to test for a colour dependence and confirm the periodicities. Results . We confirm the persistence of the previously reported 25.01 h and 23.1 min periodicities over a six-year baseline. The 25.01 h signal shows some temporal evolution, while the 23.1 min dips are highly coherent on long timescales. The previously reported transient 11.4 h feature was only detected in early TESS sectors and is absent in recent data. No significant colour dependence is found in the ground-based observations. Conclusions . The stability of the 25.01 h and 23.1 min signals indicates a long-lived, dynamically sculpted debris structure around WD 1054-226. The lack of a colour dependence implies a high optical depth, consistent with an opaque, edge-on debris ring rather than an optically thin dust population. This makes WD 1054-226 a key laboratory for testing models of remnant planetary systems around WDs.