Classical nova explosions result from the unstable ignition of hydrogen in accreted envelopes on white dwarfs (WDs) in close binary systems. Peak temperatures in the range of ∼ 2.0 – 3.5 × 108 K achieved in the ensuing thermonuclear runaway (TNR) yield the burning of hydrogen to helium, fundamentally. During this process, subsequent nuclear reactions are expected to produce peculiar isotopic abundances that differ from the nucleosynthesis results in stellar interiors or supernovae. Among such isotopes produced in TNR, lithium-7 (7Li) and nitrogen-15 (15N) are the most remarkable ones. After discovering the explosive 7Li production in a classical nova V339 Del (private communication), the following studies have been performed by the team using Subaru/HDS and other groups. These studies show that novae are considered major 7Li suppliers in the current Galaxy. In this proposal, we propose to measure abundances of 7Li from the detection 7Be at 313 nm of post-outburst nova spectra by ToO observations with Subaru/HDS to understand the complicated nucleosynthesis in TNR and to evaluate its contribution to the Galactic chemical evolution.
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