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T. E. Harrison (NMSU), S. B. Howell (PSI), H. Osborne, J. J. Johnson (NMSU), D. M. Gelino (UCSD)
The standard paradigm of cataclysmic variable (CV) evolution states that the secondary stars of CVs are relatively unevolved: There has been insufficient time for the low mass secondaries to have undergone any significant evolution off of the main sequence. Thus, the detection of enhanced/abnormal abundances, or unusual isotopic ratios, in their spectra should be rare. We have recently completed an observing run with OSIRIS that contradicts this proposition. Our new infrared spectra confirm the presence of enhanced abundances of 13C in the secondary stars of CVs, as well as suggested enhancements of Magnesium, Titanium and Sodium. There are only two processes that can explain these results. The first is that the secondary stars of CVs have undergone significant nuclear processing before becoming a contact binary. The second is that significant quantities of matter with unusual composition were deposited on the secondary star either during the common envelope phase (when the future CV secondary star orbited inside the photosphere of the white dwarf progenitor), or during classical novae explosions.
This research has been funded under NSF grant AST-9986823.
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.