HS 0209+0832 System (Artist’s Concept)

This artist’s concept depicts a possible explanation for the unusual chemical abundances the NASA/ESA Hubble Space Telescope detected in the HS 0209+0832 system: a second-generation planet orbiting the white dwarf star.

The white dwarf is the “dead” core of a star that burned through all of its nuclear fuel and lost its outer envelope of gas and dust to space. The second-generation planet formed from that cast-off gas and dust, which is why its chemical content is very different from a planet that formed as its host star was forming.

The white dwarf is still hot and is blasting the planet with radiation, causing it to lose atmosphere to space. That atmospheric material is flowing back toward the white dwarf, forming a disk and then falling back onto its surface, which is how Hubble detected the planetary chemical signatures when studying the star.

[Image description: A gaseous planet in the right foreground, seen mostly in silhouette, orbits a small, white star in the background at left. The star is surrounded by a thin, bright white disk tilted from lower left to upper right. A semi-transparent tail of material comes off the planet toward the upper right. Distant stars dot the black background of space.]