Beryllium abundances in turn-off stars of globular clusters with the CUBES spectrograph

TL;DR

This paper discusses how the upcoming CUBES spectrograph will enable the measurement of beryllium abundances in faint turn-off stars of globular clusters, providing insights into stellar population pollution and formation history.

Contribution

It demonstrates that CUBES can detect beryllium abundance variations of 0.6 dex in faint globular cluster stars, advancing studies of stellar populations.

Findings

CUBES will detect Be abundance variations of 0.6 dex in faint stars.

Simulations show potential for studying multiple stellar populations.

Enables analysis of globular clusters down to V=18 mag.

Abstract

Globular clusters host multiple stellar populations that display star-to-star variation of light elements that are affected by hot hydrogen burning (e.g., He, C, N, O). Several scenarios have been suggested to explain these variations. Most involve multiple star formation episodes, where later generations are born from material contaminated by the nucleosynthetic products of the previous stellar generation(s). One difficulty in the modelling of such scenarios is knowing the extent to which processed and pristine material are mixed. In this context, beryllium abundances measured in turn-off stars of different generations can provide new information. Beryllium originates from cosmic-ray spallation and can only be destroyed inside stars. Beryllium abundances can thus directly measure the degree of pollution of the material that formed stars in globular clusters. Turn-off stars in globular clusters are however faint and such studies are beyond the capabilities of current instrumentation. In this work, we show the progress that the CUBES spectrograph will bring to this area. Our simulations indicate that CUBES will enable the detection of variations of about 0.6 dex in the Be abundances between stars from different generations, in several nearby globular clusters with turn-off magnitude down to $V$ = 18 mag.