A very low upper limit for a Be abundance of a carbon-enhanced metal-poor star

We performed a 1D LTE chemical abundance analysis of an extremely metal-poor star BD+44◦493 ([Fe/H] = −3.7), and set a very low upper limit for its Be abundance: A(Be) < −2.0. It may indicate that the decreasing trend of Be abundances with lower [Fe/H] still holds at [Fe/H] < −3.5, and demonstrate that high C and O abundances do not necessarily imply high Be abundances. However, since the star is a subgiant with Teff ∼ 5500K, Be may be depleted.