Description
Second generation planets are formed in the post-asymptotic giant branch (AGB) phase. The synthesis of elements during the AGB phase will mean that second generation planets would have different compositions to first generation planets. Specifically, they would have enhancements in the trans-iron s-process elements.
I will present a hot (T$_\mathrm{eff}=35\,500\,$K) white dwarf which is accreting a second generation planet candidate: HS 0209+0832. It is depleted in traditional rock-forming elements such as silicon and iron but enhanced in trans-iron elements such as zinc, copper, and niobium. This is the first detection of niobium in a white dwarf. Although found as a trace element on Earth, it is an s-process element.
HS 0209+0832 also has a sinusoidal variability detected with TESS, with a period of 4.5 days and an amplitude of 0.2%. We interpret this as a close-in giant planet at a semimajor axis of 0.04au. This planet would be close enough to undergo photo-evaporation by the extreme ultraviolet photons from the hot white dwarf host.
This could be the first insight into the composition of second generation planets.
