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David Z's answer to this question got me wondering - is any appreciable amount of lithium produced as the result of a supernova explosion, either by fusion (which seems unlikely to me, but I don't have great intuition for this), or by the decay of unstable species produced by the supernova? If so, what decay chains end with lithium?

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Kyle Oman
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Lithium and other light elements (e.g. beryllium) can be formed indirectly from supernovae via cosmic ray spallation, a process where protons and neutrons are ejected when a cosmic ray collides with another atom. The nuclei can then become new elements. Nakamura & Shigeyama (2004) were able to calculate yields for 6Li, 7Li, and isotopes of Beryllium and boron from supernovae SN 1998bw, SN 2002ap, and SN 1994I. The total yield of 6Li and 7Li from each of the supernovae were 5.67$\times$10-7 M$_{\odot}$, 0.1981$\times$10-7 M$_{\odot}$, and 0.0130$\times$10-7 M$_{\odot}$, respectfully.

More specifically, the formula for indirect yield (rather, change in the number of the element over the change in time) is $$\frac{dN_l}{dt}=n_j\int_{\epsilon_{\text{Min}}}^{\epsilon_{\text{max}}}\sigma^l_{i,j}\frac{F_i(\epsilon,t)}{A_im_p}v_i(\epsilon)d\epsilon$$ via the $i+j\to l+\cdots$ reaction, where $n_j$ is number density, $\sigma^l_{i,j}$ is the reaction cross-section, and $A_i$ is the mass number. $F_i(t,\epsilon)$ is a transfer equation.

Much earlier, Truran (1973) cited Meneguzzi et al. (1971) in stating that galactic cosmic ray spallation can account for only 10% of the 7Li abundance, based on measurements in the Solar System. It is thought that supernovae were an important source of these, but they are but no means the only one. More recent estimates (e.g. Prantzos (2010)) set the upper bound at 30% (courtesy of Rob Jeffries).

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HDE 226868
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  • So "only" 10% of the lithium around the solar system was caused by high-energy particles slamming into stuff and causing nuclear fusion? – Emilio Pisanty Aug 05 '15 at 21:42
  • @EmilioPisanty In theory, yes. I should have clarified that supernovae are not the only source of cosmic rays causing spallation, though. – HDE 226868 Aug 05 '15 at 21:43
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    If you're editing, a few quick words on what spallation is wouldn't come amiss. I hadn't heard of it and I'm very, very surprised. – Emilio Pisanty Aug 05 '15 at 21:44
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    More recent work suggests that <30% of the solar system Li arises from spallation or primordial nucleosynthesis (Prantzos 2010) http://arxiv.org/pdf/1203.5662v2.pdf The majority must come from low-mass AGB stars or novae. – ProfRob Aug 05 '15 at 22:04
  • @RobJeffries Very interesting, thanks. "Primordial nucleosynthesis" referring to Big Bang nucleosynthesis? – HDE 226868 Aug 05 '15 at 22:08
  • @HDE226868 Yes. Primordial = big bang. – ProfRob Aug 05 '15 at 22:19
  • Awesome answer. Would still be curious to know whether there are any relevant decay chains ending at stable Li isotopes - is there an implicit "no" in your answer? – Kyle Oman Aug 13 '15 at 22:30
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    @KyleOman I'm not aware of any that arise from supernovae, but my knowledge of nuclear physics is far from extensive. 6He can decay to 6Li, and 8He can decay to 7Li and 8Li (the latter being unstable), but I don't think that those could be spurred on by supernovae. – HDE 226868 Aug 15 '15 at 21:41