# Central stars of planetary nebulae: The white dwarf connection

Source: [Central stars of planetary nebulae: The white dwarf connection](<https://www.sota2.com/research/paper/68fa2ff21e209131ce870a5a>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T17:52:26.650Z

Authors: K. Werner

Published: 2011-09-12T08:05:13.000Z

## Abstract

This paper is focused on the transition phase between central stars and white dwarfs, i.e. objects in the effective temperature range 100,000 - 200,000 K. We confine our review to hydrogen-deficient stars because the common H-rich objects are subject of the paper by Ziegler et al. in these proceedings. We address the claimed iron-deficiency in PG1159 stars and \[WC\] central stars. The discovery of new Ne VII and Ne VIII lines in PG1159 stars suggests that the identification of O VII and O VIII lines that are used for spectral classification of \[WCE\] stars is wrong. We then present evidence for two distinct post-AGB evolutionary sequences for H-deficient stars based on abundance analyses of the He-dominated O(He) stars and the hot DO white dwarf KPD0005+5106. Finally, we report on evidence for an H-deficient post-super AGB evolution sequence represented by the hottest known, carbon/oxygen-atmosphere white dwarf H1504+65 and the recently discovered carbon-atmosphere "hot DQ" white dwarfs.

## Recorded benchmark results

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1109.2391>)

[PDF](<https://arxiv.org/pdf/1109.2391.pdf>)