Description
The recent discoveries of transits around white dwarfs have provided unique and powerful insights into their circumstellar debris discs. This family of white dwarfs with transiting debris exhibits significant diversity, where some display line-of-sight gas absorption while others are highly dynamic with large scale heights.
In 2022, a white dwarf was reported to have transiting debris at an orbital period of 25h, which places its circumstellar material in the habitable zone, where a planetary surface can support liquid water. The light curves show myriad unusual features, with the most pronounced dimming components every 23 min – the 65th harmonic of the fundamental period – and numerous orbital drifters.
I will present time-resolved X-Shooter spectroscopic data of WD1054–226, which demonstrate significant spectroscopic variability, a hallmark of circumstellar gas along the line of sight. Our team has also obtained ultraviolet spectra with Hubble, which will crucially allow us to differentiate between volatile and refractory compositions of the parent body, and near-infrared light curves from HAWK-I, which enable investigations into the colour dependence, and therefore the size distribution, of the transiting material. Finally, an update will be provided on the long-term stability of the 65th harmonic and the presence of the drifting components over a timescale of four years, facilitated by new multi-band light curves from ULTRACAM.
