White Dwarf HS 0209+0832 over Time (artist’s concept)

In this (not-to-scale) artist’s concept, a lower-mass star like the Sun (1) ages into a puffy red giant star (2) that eventually expels its outer envelope of gas and dust into space, which forms a disk around the bright cinder of its remaining core, called a white dwarf (3). A second-generation planet forms in this disk, orbiting the white dwarf and losing some of its atmosphere back onto the white dwarf’s surface (4).

[Image description: Illustration divided into quadrants, showing the evolution of a star system over time. The upper left is labeled 1. Sun-like star. It shows a small, glowing yellow star centered with other faint stars in the background of space. The upper right quadrant is labeled 2. Red giant. It shows a much larger, puffy orange-red star with a yellow glow within. The bottom left quadrant is labeled 3. White dwarf with second-generation protoplanetary disk, showing a bright white star, smaller than the original Sun-like star, surrounded by a glowing dusty blueish-white disk that is brighter closer to the star. The lower right quadrant is labeled 4. Accretion of a second-generation planet. It shows a similar star to quadrant 3, but the disk is reduced in size and is more purple in color. A planet orbits to the lower left of the star. The planet is larger than the star and has a faint tail leading back to the disk around the star.]