Lithium detected in an ancient star gives new clues for Big Bang nucleosynthesis | 4/3/2019 | Staff
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ISIS spectrum of J0023+0307, and J1029+1729, one of the most metal-poor stars known and shown for comparison. In red, the best model fit. Figure taken from Aguado et al., 2018.

Researchers from the Instituto de Astrofísica de Canarias (Spain) and the University of Cambridge (UK) have detected lithium (Li) in the ancient star J0023+0307, a main-sequence extremely iron-poor dwarf star about 9,450 light years away in the galactic halo.

Study - Stars - Milky - Way - Properties

The study of the most ancient stars in the Milky Way allows us to infer the early properties of the galaxy, its chemical composition, and its assembly history. Metal-poor stars are invaluable messengers that carry information from early epochs, and are an important key to understand the primordial production of Li and the processes responsible for the possible "meltdown" of the Li plateau (a typical Li abundance of a metal-poor dwarf star which is related to the primordial lithium abundance). All stars with low metallicities and low Li abundances, significantly below A(Li)~2.2, are considered to have been likely affected by destruction of the Li in the stars.

New or poorly measured nuclear reaction resonances could affect the Li production predicted by the standard Big Bang nucleosynthesis (SBBN). Processes injecting neutrons at the relevant temperatures of the primordial plasma can also alter the primordial Li abundance. In addition, time-varying fundamental constants may lead to a significant Li lower value. Li observations in stars at the lowest metallicities are especially important to bring an insight into the processes of potential Li depletion in stars and, ultimately, to establish if any non-standard physics may have played a role during or after SBBN.

Stars - Generation - Objects

Stars that formed in the first or second generation are extremely rare objects, and only a few are...
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