Where are the Extrasolar Mercuries?
Alexandra E. Doyle, Beth Klein, Hilke E. Schlichting, Edward D. Young

TL;DR
This study analyzes the oxidation states of rocky bodies accreting onto white dwarfs, revealing most formed under oxidizing conditions, with some evidence of reduced bodies, and discusses the challenges in accurately determining their compositions.
Contribution
It introduces a method to assess oxidation states of extrasolar rocky bodies using white dwarf observations and models their evolution, highlighting the prevalence of oxidizing conditions and detection biases.
Findings
Most extrasolar rocky bodies formed under oxidizing conditions.
Approximately 25% of polluted white dwarfs have reduced parent bodies.
Detection biases favor oxidized bodies at high temperatures.
Abstract
We utilize observations of 16 white dwarf stars to calculate and analyze the oxidation states of the parent bodies accreting onto the stars. Oxygen fugacity, a measure of overall oxidation state for rocks, is as important as pressure and temperature in determining the structure of a planet. We find that most of the extrasolar rocky bodies formed under oxidizing conditions, but approximately 1/4 of the polluted white dwarfs have compositions consistent with more reduced parent bodies. The difficulty in constraining the oxidation states of relatively reduced bodies is discussed and a model for the time-dependent evolution of the apparent oxygen fugacity for a hypothetical reduced body engulfed by a WD is investigated. Differences in diffusive fluxes of various elements through the WD envelope yield spurious inferred bulk elemental compositions and oxidation states of the accreting parent…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
