On Possible Oxygen/Neon White Dwarfs: H1504+65 and the White Dwarf Donors in Ultracompact X-ray Binaries

K. Werner; N. J. Hammer; T. Nagel; T. Rauch; S. Dreizler

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On Possible Oxygen/Neon White Dwarfs: H1504+65 and the White Dwarf Donors in Ultracompact X-ray Binaries

K. Werner·N. J. Hammer·T. Nagel·T. Rauch·S. Dreizler

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Abstract

We discuss the possibility to detect O/Ne white dwarfs by evidence for Ne overabundances. The hottest known WD, H1504+65, could be the only single WD for which we might be able to proof its O/Ne nature directly. Apart from this, strong Ne abundances are known or suspected only from binary systems, namely from a few novae, and from a handful of LMXBs. We try to verify the hypothesis that the latter might host strongly ablated O/Ne WD donors, by abundance analyses of the accretion disks in these systems. In any case, to conclude on O/Ne WDs just by strong Ne overabundances is problematic, because Ne enrichment also occurs by settling of this species into the core of C/O WDs.

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K. Werner, N. J. Hammer, T. Nagel, T. Rauch, S. Dreizler. 2004-10-28. On Possible Oxygen/Neon White Dwarfs: H1504+65 and the White Dwarf Donors in Ultracompact X-ray Binaries. https://arxiv.org/abs/astro-ph/0410690

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