J. Korth, A. J. Mustill, H. Parviainen, E. Villaver, J. W. Kuehne, V. J. S. Béjar, Y. Hayashi, N. Abreu García, T. Kagetani, K. Kawauchi, L. Livingston, M. Mori, G. Morello, N. Watanabe, I. Fukuda, K. Ikuta, I. Bonilla-Mariana, E. Esparza-Borges, G. Fernández-Rodríguez, A. Fukui, S. Geraldía-González, J. González-Rodríguez, K. Isogai, N. Narita, E. Palle, A. Peláez-Torres, M. Sánchez-Benavente

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. We aim to 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. We analyse all available TESS light curves from Sectors 9, 36, 63, and 90 using Lomb-Scargle (LS), Box-Least-Squares (BLS), and Gaussian process (GP) periodogram analyses. We complement these with multiband, high-cadence ground-based photometry from LCOGT, MuSCAT2, ALFOSC, and ProEM to test for colour dependence and confirm the periodicities. 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. A transient 11.4 h feature, previously reported, is detected only in early TESS sectors and is absent in recent data. No significant colour dependence is found in the ground-based observations. The stability of both the 25.01 h and 23.1 min signals indicates a long-lived, dynamically sculpted debris structure around WD 1054-226. The lack of colour dependence implies 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 white dwarfs.