Artist’s animation of WD 0816-310, a magnetic white dwarf, ingesting planetary fragments

This artist’s animation shows the magnetic white dwarf WD 0816-310, a dead star that has a scar imprinted on its surface as a result of having ingested planetary debris.

When objects like planets or asteroids approach the white dwarf they become fragmented, forming a debris disc around the dead star, as seen in this animation. Some of this material can be devoured by the dwarf, leaving traces of certain chemical elements on its surface. 

Using observations from ESO’s Very Large Telescope, astronomers found that the signature of these chemical elements changed periodically as the star rotated, as did the magnetic field. This indicates that the magnetic fields funneled these charged elements onto the star’s surface, channeled along its field lines to each pole as seen here. At the end of the animation, a close-up shows the elements being concentrated by the magnetic field at one of the poles, forming a scar.

For more details, check the corresponding press release.