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A metal disc around a white dwarf

We have discovered a single white dwarf in the Sloan Digital Sky Survey that displays strong double-peaked emission lines lines of CaII in the I-band. The line profiles unambiguously show that the metal gas is rotating in a very close orbit at about one solar radius around the white dwarf. Time-resolved spectroscopy and photometry obtained at the William Herschel Telescope and the Isaac Newton Telescope of the Isaac Newton Group show that the white dwarf is a single star, ruling out that the disc material is originating from a nearby companion star. The only plausible origin for the metal rich gas is an asteroid that has been tidally disrupted as it approached the white dwarf, and subsequently evaporated. This research has been published in Science and the unedited manuscript is available on ArXiV.

Warwick press release

Press cuttings: The Guardian, Scientific American