Arcturus Lab (line list)

The current generation of NIR echelle spectrographs enables the sampling of many spectral features over the full 0.9-2.4um range for a detailed chemical tagging. Within the Stellar Population Astrophysics Large Program at the TNG, we used a high-resolution (R=50000) NIR spectrum of Arcturus acquired with the GIANO-B echelle spectrograph as a laboratory to define and calibrate an optimal line list and new diagnostic tools to derive accurate stellar parameters and chemical abundances.

We inspected several hundreds of NIR atomic and molecular lines to derive abundances of 26 different chemical species, including CNO, iron-group, alpha, Z-odd and neutron-capture elements. We then performed a similar analysis in the optical using Arcturus VLT-UVES spectra. By the combined NIR and optical analysis we defined a new thermometer and a new gravitometer for giant stars, based on the comparison of Carbon and Oxygen abundances, respectively, as derived from atomic and molecular lines.