Relentless and complex transits from a planetesimal debris disc

ABSTRACT This article reports quasi-continuous transiting events towards WD 1054–226 at d = 36.2 pc and V 16.0 mag, based on simultaneous, high-cadence, multiwavelength imaging photometry using ULTRACAM over 18 nights from 2019 to 2020 March. The predominant period is 25.02 h corresponds a circular orbit with blackbody Teq 323 K, where planetary surface can nominally support liquid water. light curves reveal remarkable night-to-night similarity, changes longer time-scales, lack any transit-free segments of unocculted starlight. most pronounced dimming components occur every 23.1 min – exactly the 65th harmonic fundamental depths up several per cent, no evident colour dependence. Myriad additional harmonics are present, as well least two features independent periods. High-resolution optical spectra consistent stable, photospheric absorption by multiple, refractory metal species, indication circumstellar gas. Spitzer observations demonstrate detectable dust emission, suggesting that otherwise hidden disc orbiting may be typical polluted white dwarfs, detected only via favourable geometry. Future required constrain orbital eccentricity, but even if periastron near Roche limit, sublimation cannot drive mass loss in parent bodies, collisional disintegration necessary for production.