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

Le résumé fourni par la source

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. At the time of publishing, PEWDD contains 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 the metals that are detectable strongly correlate with the effective temperature. By considering metal-enriched white dwarfs that have abundances measured by different methods, we find a spread that is comparable with the often-quoted ad hoc estimated abundance uncertainties, namely ≃0.1−0.2 dex. We draw attention to a dichotomy in the median accretion rates for metal-enriched H- and He-dominated white dwarfs, with Ṁacc,H = 7.7 × 107g s−1 and Ṁacc,He = 8.7 × 108g s−1, when extrapolating bulk compositions from bulk Earth Ca abundance. We identified 40 metal-enriched white dwarfs in binary systems and find evidence that enrichment is suppressed by binary companions within 200 au.

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