Oscillator Strength Measurements of Atomic Absorption Lines from Stellar Spectra

摘要

We develop a new method to determine oscillator strength values of atomicabsorption lines with state-of-the-art detailed spectral synthesis calculationsof the optical spectrum of the Sun and of standard spectral reference stars. Weupdate the log(gf)-values of 911 neutral lines observed in the KPNO-FTS fluxspectrum of the Sun and high-resolution echelle spectra (R=80,000) of Procyon(F5 IV-V) and {\epsilon} Eri (K2 V) observed with large signal-to-noise (S/N)ratios of ~2,000 using the new Mercator-Hermes spectrograph at La PalmaObservatory (Spain). We find for 483 Fe I, 85 Ni I, and 51 Si I absorptionlines in the sample a systematic over-estimation of the literaturelog(gf)-values with central line depths below 15 %. We employ a curve-of-growthanalysis technique to test the accuracy of the new oscillator strength valuesand compare calculated equivalent line widths to the Moore, Minnaert, &Houtgast atlas of the Sun. The online SpectroWeb database athttp://spectra.freeshell.org interactively displays the observed and syntheticspectra and provides the new log(gf)-values together with important atomic linedata. The graphical database is under development for stellar reference spectraof every spectral sub-class observed with large spectral resolution and S/Nratios.