Speaker
Description
Abstract—The cosmological lithium problem is one of the
biggest discrepancies between Big Bang nucleosynthesis predictions and stellar observations. In this paper, we measure the first
Spite Plateau data with the latest GALAH DR4 survey. After we
apply cuts to the data to isolate warm, metal-poor dwarf stars,
we analyze lithium abundance compared to metallicity using
the Bayesian regression code ROXY, which also accounts for
uncertainties in Spite Plateau data. This allows us to calculate
the slope, intercept, and scatter of Spite Plateau stars across
varying metallicity cuts.
Across all metallicity cuts to [F e/H] < −2.0, the slopes remain
at zero within uncertainties, confirming that the Spite Plateau has
a flat relationship at low metallicity. These findings demonstrate
that even with modern surveys and advanced Bayesian regression
tools, there is no explanation for the Spite Plateau. Even with
modern tools, the oldest stars appear to have near constant
lithium with a strong discrepancy with the value expected from
Big Bang Nucleosynthesis, which continues to be an open problem
in cosmology and stellar astrophysics.
Index Terms—Big Bang Nucleosynthesis, Spite Plateau,
Lithium Abundance, Bayesian Regression, Stellar Astrophysics