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.
