Metal Abundances in Hot DO White Dwarfs

TL;DR

This paper investigates the chemical compositions of hot DO white dwarfs, revealing their evolutionary origins and the processes influencing their metal abundances, including s-process nucleosynthesis and binary mergers.

Contribution

It provides new insights into the evolutionary pathways of hot DO white dwarfs through detailed analysis of their metal abundances and origins.

Findings

RE0503-289 shows high carbon and trans-Fe element abundances from s-process nucleosynthesis.

KPD0005+5106 likely results from a binary white dwarf merger, not from PG1159 progenitors.

Different evolutionary sequences are identified for the hottest DO white dwarfs.

Abstract

The relatively high abundance of carbon in the hot DO white dwarf RE0503-289 indicates that it is a descendant of a PG1159 star. This is corroborated by the recent detection of the extremely high abundances of trans-Fe elements which stem from s-process nucleosynthesis in the precursor AGB star, dredged up by a late He-shell flash and possibly amplified by radiative levitation. On the other hand, the hottest known DO white dwarf, KPD0005+5106, cannot have evolved from a PG1159 star but represents a distinct He-rich evolutionary sequence that possibly originates from a binary white dwarf merger.