Stellar astrophysics in the near UV with VLT-CUBES

TL;DR

This paper evaluates the capabilities of the upcoming VLT-CUBES spectrograph for near-UV stellar observations, highlighting its potential for chemical abundance analysis compared to existing instruments like VLT-UVES.

Contribution

It provides a detailed comparison of spectral resolution and element detectability between CUBES and UVES, informing future near-UV astrophysical research.

Findings

Most spectral lines are more affected by signal-to-noise ratio than resolution.

CUBES can observe key elements like Be, Ge, and Hf at R~20,000.

Certain elements are now being quantitatively simulated for future studies.

Abstract

Alongside future observations with the new European Extremely Large Telescope (ELT), optimised instruments on the 8-10m generation of telescopes will still be competitive at 'ground UV' wavelengths (3000-4000 A). The near UV provides a wealth of unique information on the nucleosynthesis of iron-peak elements, molecules, and neutron-capture elements. In the context of development of the near-UV CUBES spectrograph for ESO's Very Large Telescope (VLT), we are investigating the impact of spectral resolution on the ability to estimate chemical abundances for beryllium and more than 30 iron-peak and heavy elements. From work ahead of the Phase A conceptual design of CUBES, here we present a comparison of the elements observable at the notional resolving power of CUBES (R~20,000) to those with VLT-UVES (R~40,000). For most of the considered lines signal-to-noise is a more critical factor than resolution. We summarise the elements accessible with CUBES, several of which (e.g. Be, Ge, Hf) are now the focus of quantitative simulations as part of the ongoing Phase A study.