Abstract The Ca ii H and K lines are among the few features available to infer metallicity of extremely metal-poor stars from medium-resolution spectroscopy. Unfortunately, these can overlap with absorption produced in intervening interstellar medium, introducing systematic errors derived metallicities. strength infrared triplet also be measured at low metallicities, it is not affected by absor...

We explore the stellar content of Javalambre Photometric Local Universe Survey (J-PLUS) Data Release 2 and show its potential to identify low-metallicity stars using Stellar Parameters Estimation based on Ensemble Methods (SPEEM) pipeline. SPEEM is a tool provide determinations atmospheric parameters for separate sources from quasars, unique J-PLUS photometric system. The adoption adequate sele...

Detailed chemical abundances of very metal-poor (VMP, [Fe/H] < -2) stars are important for better understanding the First Stars, early star formation and enrichment galaxies. Big on-going coming high-resolution spectroscopic surveys provide a wealth material that needs to be carefully analysed. For VMP stars, their elemental should derived based on non-local thermodynamic equilibrium (non-LTE =...