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Search For Oxygen in Cool DQ White Dwarf Atmospheres

M. Kilic·D. E. Winget·T. von Hippel·D. F. Lester·D. Saumon
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Abstract

We report new infrared spectroscopic observations of cool DQ white dwarfs by using Coolspec on the 2.7m Harlan-Smith Telescope. DQs have helium-rich atmospheres with traces of molecular carbon thought to be the result of convective dredge-up from their C/O interiors. Recent model calculations predict that oxygen should also be present in DQ atmospheres in detectable amounts. Our synthetic spectra calculations for He-rich white dwarfs with traces of C and O indicate that CO should be easily detected in the cool DQ atmospheres if present in the expected amounts. Determination of the oxygen abundance in the atmosphere will reveal the C/O ratio at the core/envelope boundary, constraining the important and uncertain ^{12}C(alpha,gamma)^{16}O reaction rate.

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M. Kilic, D. E. Winget, T. von Hippel, D. F. Lester, D. Saumon. 2002-09-15. Search For Oxygen in Cool DQ White Dwarf Atmospheres. https://arxiv.org/abs/astro-ph/0209286

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