wavelengths (Izquierdo et al, 2018). Recently this system has become more quiescent (Aungwerojwit et al, 2024), showing that these transiting phenomena are transitory on human-relevant timescales. This raises the prospect that revisiting previously-surveyed WDs with non-detections could
13An earlier discovery, a super-Jovian companion to WD0806-661 at 2500 au projected separation, is often regarded as a brown dwarf owing to its large mass and very large separation Luhman et al (2011); Rodriguez et al (2011).

in future yield more detections, as fresh material is delivered to the WD or existing material which was previously inactive and unseen undergoes more outbursts, collisions, and dust production.
Since the WD1145 transit detections were first recorded, transits have been detected around several more WDs. Just under 1% of metal-polluted WDs exhibit transits, which is consistent with all such WDs having detectable material in orbit once the geometric transit probability is accounted for (Robert et al, 2024). WD1856+534 (Vanderburg et al, 2020) is a typical hot Jupiter on a 1.4-day orbit, save for the fact that it orbits a WD rather than a Main Sequence star. ZTF J1944+4557 resembles WD1145 in its period (4.9 hr), and also became quiescent after discovery, although its transits have subsequently re-appeared (Guidry et al, 2025). ZTF J0328-1219 (Vanderbosch et al, 2021) exhibits recurrent features similar to WD1145, but at longer periods of 9.9 and 11.2 hr, pointing to sublimation, rather than Roche lobe overflow, as the mechanism for generating the activity; SBSS 1232+563 shows a signal with a comparable 14.8 hr period, along with a 40% flux drop lasting for 8 months (Hermes et al, 2025). ZTF J0139+5245 on the other hand exhibits recurring transits with a long period of 107 days, with a pronounced cometary morphology (Vanderbosch et al, 2020); see Fig 6B,F. These likely arise from a body on an eccentric orbit in the process of orbital circulation, be that due to tidal or radiation forces (Veras et al, 2015c); note that, with a period of 107 days, the apapsis of such an orbit must still be considerably interior to the expected source region at ≳10 au, indicating some orbital decay since the body was injected from the source region. Apart from the planet WD1856b, these transits are all variable with time, in terms of depth and precise morphology, further evidence of the comet-like, rather than solid, nature of the occluding material. Perhaps the most complex transiting system yet found is WD1054-226 (Farihi et al, 2022). In this system, there is no flat, out-of transit baseline; rather, the stellar light curve is constantly varying, with two dominant periods: one at 25 hours, and one at 23 minutes. These lie on a 65:1 commensurability, suggesting some kind of resonant interaction between a disc of material and a perturbing planet or asteroid14. This could involve the disc material being concentrated in resonant clumps (e.g., Wyatt, 2003), or the perturber exciting a standing wave in the disc as seen in ring–moon interactions in the Saturnian system (e.g., Cuzzi et al, 1981), although models here are lacking. On short time-scales (night-to-night), the detailed light-curve features such as double-dips align well when phase-folded on the 25-hour period; on longer time-scales of several years, the detailed features vary but the dominant frequencies remain (Farihi et al, 2022; Korth et al, 2026a).
The discovery of these systems is now accelerating, with Bhattacharjee et al (2025) presenting 6 new candidates from an automated analysis of Zwicky Transient Facility (ZTF) light curves. One of these systems, WD J1013-0427, shows the first reddened transits of dust clouds in front of a white dwarf, providing evidence for sub-micron grains15. This is in contrast not only to WD1145+017 (Alonso et al, 2016; Izquierdo et al, 2018; Xu et al, 2018a) but also to several other WDs which also exhibit grey
14The 65:1 commensurability is between the observed periods; this likely implies not a 65:1 mean motion resonance, but a 66:65.
15Previously, (Hallakoun et al, 2017) had detected bluing during transits of WD1145+017, attributed to gas absorption during transit rather than dust properties.