COSMO
In the literature: open
What is the lithium abundance in gas never processed by stars?
In plain words
Measuring lithium in interstellar gas of a nearly pristine galaxy would avoid any doubt about stars destroying it. Such measurements are difficult because the lithium absorption line is very weak.
Precise statement
Measure Li/H in the interstellar medium of a galaxy with metallicity below 0.1 solar, corrected for depletion onto dust and cosmic-ray production, with 20 percent precision. A 2012 measurement in the Small Magellanic Cloud gave a value consistent with BBN but with large errors and some galactic enrichment (moderate confidence on values).
What would settle it
High-resolution ultraviolet and optical spectroscopy of Li I absorption toward bright stars or quasars behind low-metallicity gas with extremely large telescopes.
Related problems
- Special case of What explains the threefold lithium-7 deficit in old halo stars?