Free Astronomy Magazine January-February 2020

17 JANUARY-FEBRUARY 2020 SPACE CHRONICLES that there had to be something ex- ceptional going on in this system, and speculated that it may be related to some type of planetary remnant.” To get a better idea of the proper- ties of this unusual star, named WDJ0914+1914, the team analysed it with the X-shooter instrument on ESO’s Very Large Telescope in the Chilean Atacama Desert. These fol- low-up observations confirmed the presence of hydrogen, oxygen and sulphur associated with the white dwarf. By studying the fine details in the spectra taken by ESO’s X- shooter, the team discovered that these elements were in a disc of gas swirling into the white dwarf, and not coming from the star itself. “It took a few weeks of very hard thinking to figure out that the only way to make such a disc is the evap- oration of a giant planet,” says Matthias Schreiber from the Univer- sity of Valparaiso in Chile, who com- T his illustration shows the white dwarf WDJ0914+1914 and its Neptune-like exoplanet. Since the icy giant orbits the hot white dwarf at close range, the extreme ultravi- olet radiation from the star strips away the planet’s atmosphere. While most of this stripped gas es- capes, some of it swirls into a disc, itself accreting onto the white dwarf. [ESO/M. Kornmesser]