Laboratory Spectroscopy of Neutral Scandium, Sc I, for Astrophysical Applications

Sammanfattning: Most of the things that we know about stars come from their spectrum. The properties of the atomic lines, e.g. energy levels, wavelengths, oscillator strengths, must be known to understand the observed spectrum and to perform quantitative analyses. Atomic data of some elements are incomplete, especially in the near-infrared region, which makes it difficult or even impossible to analyze a stellar spectrum or do abundance analysis. The purpose of this master project is to investigate the spectrum of neutral scandium, Sc I, from laboratory measurements and to improve the atomic data of Sc I ions. A hollow cathode discharge lamp (HCL) is usedto produce the spectra of scandium and a Fourier transform spectrometer (FTS) is used to record the spectra. The high resolution, intensity calibrated spectra are used to derive accurate laboratory wavelengths and oscillator strengths for Sc I lines, with emphasis on the infrared region 0.7-5 microm. This is the spectral region covered by recent astronomical observatories, e.g. RIRES at VLT, and also the next generation telescopes. The present work provide a set of experimental Sc I lines in the infrared region for accurate spectral analysis of astronomical objects.