Analysis of the spectrum of the star GD61 shows a lot of planetary compounds including water, which suggests that the star is consuming icy planetary bodies 

Spitzer observations reveal the presence of warm debris from a tidally destroyed rocky and possibly icy planetary body, orbiting the white dwarf-star GD61.

Ultraviolet and optical spectroscopy of the metal-contaminated stellar photosphere reveal traces of hydrogen, oxygen, magnesium, silicon, iron, and calcium; The nominal ratios of these elements indicate an excess of oxygen relative to that expected from rock-forming metal oxides, and thus it is possible that water was accreted together with the terrestrial-like debris.

Iron is found to be deficient relative to magnesium and silicon, suggesting the material may have originated as the outer layers of a differentiated parent body, as is widely accepted for the Moon

Source: arxiv.org (pdf)