PEWDD: A database of white dwarfs enriched by exo-planetary material

TL;DR

PEWDD is a comprehensive database compiling white dwarf stars with planetary debris signatures, revealing observational biases, accretion rate differences based on atmospheric composition, and the impact of binary companions on metal enrichment.

Contribution

The paper introduces PEWDD, a new extensive database of white dwarf abundances and properties related to planetary debris, with analysis of observational effects and binary influence.

Findings

Metal detection correlates with effective temperature.

Significant spread in abundance measurements across methods.

Binary companions within 200au suppress metal enrichment.

Abstract

We present the Planetary Enriched White Dwarf Database (PEWDD), a collection of published photospheric abundances of white dwarfs accreting planetary debris alongside additional information relevant to metal-enrichment and the presence of infrared excesses, emission lines, and binary companions. PEWDD contains at the time of publishing information on 1739 white dwarfs and will be kept up-to-date with information from new publications. A total of 24 photospheric metals are recorded and are linked to accretion of exo-planetary material. The overall properties of metal-enriched white dwarfs are severely affected by observational selection effects; in particular we find that what metals are detectable strongly correlates with the effective temperature. By considering metal-enriched white dwarfs which have abundances measured by different methods, we find a spread that is comparable with the often quoted ad-hoc estimated abundance uncertainties, i.e. ~0.1-0.2dex. We draw attention to a dichotomy in the median accretion rates for metal-enriched H- and He-dominated white dwarfs, with M_{acc, H} = 7.7e7g/s and M_{acc, He} = 8.7e8g/s when extrapolating bulk compositions from bulk Earth Ca abundance. We identify 40 metal-enriched white dwarfs in binary systems and find evidence that enrichment is suppressed by binary companions within 200au.