“CONSTRUINDO UMA ABRANGENTE LISTA DE LINHAS ESPECTRAIS PARA ESPECTROSCOPIA NO INFRAVERMELHO PRÓXIMO DE λ 1–5 μM”

Abstract

Spectral line lists constitute the foundation for spectral synthesis calculations and the determination of chemical abundances, including those derived from large spectroscopic surveys such as SDSS–APOGEE. This project extended beyond the APOGEE spectral region (between λ 1.5 and 1.7, μm) and produced a new and comprehensive atomic and molecular line list covering the wavelength range λ 1 to 5, μm. Currently available atomic and molecular data were critically reviewed and consolidated into an updated line list, spanning a spectral range compatible with several combinations of ground-based telescopes and spectrographs, as well as with the NIRSpec spectrograph aboard the James Webb Space Telescope. The line list was constructed in the format accepted by the spectral synthesis code Turbospectrum, which was used to generate the synthetic spectra employed for comparison with the observed spectra. The atomic and molecular data were evaluated through comparisons with the benchmark stars the Sun, Arcturus, and an M dwarf with previously determined parameters, using high-quality, high-resolution near-infrared spectra. The inclusion of an M-type dwarf star in the fitting and validation processes is essential, as these stars exhibit a high molecular concentration in the spectral region λ = 1 to 5μm, producing a pseudo-continuum strongly dominated by molecular features, such as those of H2O and FeH. Once the line list was completed, we focused on the analysis of spectra of Barnard’s Star, determining its effective temperature, surface gravity, metallicity, and chemical abundances using the BACCHUS code, and subsequently employing this star to validate the line list developed in this work.