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arXiv · 1601.05168

The $^{7}$Be II Resonance Lines in Two Classical Novae V5668 Sgr and V2944 Oph

Akito Tajitsu·Kozo Sadakane·Hiroyuki Naito·Akira Arai·Hideyo Kawakita·Wako Aoki
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Abstract

We report spectroscopic observations of the resonance lines of singly ionized $^{7}$Be in the blue-shifted absorption line systems found in the post-outburst spectra of two classical novae -- V5668 Sgr (Nova Sagittarii 2015 No.2) and V2944 Oph (Nova Ophiuchi 2015). The unstable isotope, $^{7}$Be, should has been created during the thermonuclear runaway (TNR) of these novae and decays to form $^{7}$Li within a short period (a half-life of 53.22 days). Confirmations of $^{7}$Be are the second and the third ones following the first case found in V339 Del by Tajitsu et al. (2015). The blue-shifted absorption line systems in both novae are clearly divided into two velocity components, both of which contain $^{7}$Be. This means that the absorbing gases in both velocity components consist of products of TNR. We estimate amounts of $^{7}$Be produced during outbursts of both novae and conclude that significant $^{7}$Li should have been created. These findings strongly suggest that the explosive production of $^{7}$Li via the reaction $^{3}$He($α$,$γ$)$^{7}$Be and subsequent decay to $^{7}$Li occurs frequently among classical novae and contributes to the process of the Galactic Li enrichment.

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Akito Tajitsu, Kozo Sadakane, Hiroyuki Naito, Akira Arai, Hideyo Kawakita, Wako Aoki. 2016-01-20. The $^{7}$Be II Resonance Lines in Two Classical Novae V5668 Sgr and V2944 Oph. https://doi.org/10.3847/0004-637x%2F818%2F2%2F191

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