Published online by Cambridge University Press: 12 April 2016
Abundance determinations for the ejected shells of classical novae are reviewed. Substantial enrichments (relative to hydrogen) of helium, the CNO elements, and elements in the range from neon to aluminum are found to be characteristic of nova ejecta. The source of these enrichments is believed to be the dredge-up of underlying white dwarf core matter, thus reflecting the white dwarf composition and confirming the presence of oxygen-neon-magnesium (ONeMg) as well as carbon-oxygen (CO) degenerate dwarfs in cataclysmic variable systems. The implications of these abundance enrichments, for the behavior of nova systems in outburst and for nucleosynthesis, are examined.