Software development for heavy element abundance analysis of very metal-poor stars from lines in the ultraviolet

• Ano de defesa: 2024
• Autor(a) principal: Castro, Matheus de Jesus
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Abundâncias químicas; Atmosferas estelares; Chemical abundances; Síntese espectral; Spectral synthesis; Stellar atmospheres
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/14/14131/tde-18022025-102451/

The First Stars program in the early 2000s collected high-resolution spectra of very metal-poor stars over 37 nights in the VLT. The data were analyzed and published in a series of 16 papers. The now ongoing project to build the CUBES spectrograph, to be installed at the VLT, will allow reaching stars with 18.0 in the near-UV, enlarging considerably the number of reachable metal-poor stars. For this reason, it was realized that a finer work on available lines in the near-UV of the stars observed in the First Stars project should be further developed. In this dissertation, the work on the halo metal-poor star CS 31082-001, which was revealed to be r-process-rich, has been revised. A series of spectral lines of heavy elements is studied, with a good number of them not studied before. The motivation for this extended work is the use of CUBES Spectrograph in the future. The results obtained from the CS 31082-001 were published in the paper Reanalysis of neutron-capture elements in the benchmark r-rich star CS 31082-001 in MNRAS. The Multiple Element Abundance Fitting Software (MEAFS) was developed to help with measuring equivalent widths and abundances with a minimum interaction and high precision results. The software uses a combination of the Chi-square method and the Nelder-Mead minimization to find chemical abundances of elements and create plots for analysis.