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		| Paper: | 
		On Possible Oxygen/Neon White Dwarfs: H1504+65 and the White Dwarf Donors in Ultracompact X-ray Binaries | 
	 
	
		| Volume: | 
		334, 14th European Workshop on White Dwarfs | 
	 
	
		| Page: | 
		165 | 
	 
	
		| Authors: | 
		Werner, K.; Hammer, N.J.; Nagel, T.; Rauch, T.; Dreizler, S. | 
	 
	
	
		| 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 prove 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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