Credit: NASA/JPL-Caltech/J. Farihi (Univ. of Leicester)

This chart shows the brightness and wavelength of the radiation coming from white dwarf GD 16 and its associated disk of closely orbiting rocky material. The data was obtained with NASA's Spitzer Space Telescope. The colored data points indicate hot emission from the white dwarf (left of the graph) and cool emission from the surrounding material (right hand side).

White dwarfs are the remnants of relatively low-mass stars that have passed through their red giant stage. A white dwarf may be the size of the Earth, but contain the same mass as the Sun. This star remnant is so dense, in fact, that one teaspoon of white dwarf material would weigh several tons. Over 90% of all stars -- including our Sun -- will end their lives as white dwarfs.