Absence of a correlation between white dwarf planetary accretion and primordial stellar metallicity

Sydney Jenkins*, Andrew Vanderburg, Allyson Bieryla, David W. Latham, Mariona Badenas-Agusti, Perry Berlind, Simon Blouin, Lars A. Buchhave, Michael L. Calkins, Gilbert A. Esquerdo, Javier Viaña

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Over a quarter of white dwarfs have photospheric metal pollution, which is evidence for recent accretion of exoplanetary material. While a wide range of mechanisms have been proposed to account for this pollution, there are currently few observational constraints to differentiate between them. To investigate the driving mechanism, we observe a sample of polluted and non-polluted white dwarfs in wide binary systems with main-sequence stars. Using the companion stars' metallicities as a proxy for the white dwarfs' primordial metallicities, we compare the metallicities of polluted and non-polluted systems. Because there is a well-known correlation between giant planet occurrence and higher metallicity (with a stronger correlation for close-in and eccentric planets), these metallicity distributions can be used to probe the role of gas giants in white dwarf accretion. We find that the metallicity distributions of polluted and non-polluted systems are consistent with the hypothesis that both samples have the same underlying metallicity distribution. However, we note that this result is likely biased by several selection effects. Additionally, we find no significant trend between white dwarf accretion rates and metallicity. These findings suggest that giant planets are not the dominant cause of white dwarf accretion events in binary systems.

Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society
Volume532
Issue number1
Pages (from-to)394-410
ISSN0035-8711
DOIs
Publication statusPublished - 2024

Keywords

  • Planet-star interactions
  • Planets and satellites: dynamical evolution and stability
  • Stars: abundances
  • White dwarfs

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