Mostrar registro simples

dc.contributor.advisorRomero, Alejandra Danielapt_BR
dc.contributor.authorRamos, Gabriel Laufferpt_BR
dc.date.accessioned2018-08-08T02:33:14Zpt_BR
dc.date.issued2018pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/181005pt_BR
dc.description.abstractWhite dwarf stars are the most common final stage of stellar evolution, corresponding to 99% of all stars in the Galaxy. White dwarf models can be used to obtain the age of stellar populations, to build an initial to final mass relation to understand the connection between the properties of white dwarfs and their progenitors, determine the upper mass limit that separates white dwarfs progenitors from Type II supernovae, enhance the comprehension of the physical properties of high density matter and derive ages and masses for observed white dwarfs from the cooling tracks. The literature is populated with low mass and intermediate mass white dwarf models, however the massive white dwarfs are often forgotten and the evolutionary sequences are incomplete. In this dissertation, we compute full evolutionary sequences for massive white dwarfs, exploring the evolution of hydrogen-rich and hydrogen-deficient white dwarfs stars with masses between 1.012 and 1.307 M , and initial metallicity of Z = 0.02. These sequences are the result of main sequence stars with masses between 8.8 and 11.8 M . The simulations were performed with the Modules for Experiments in Stellar Astrophysics - MESA code, starting at the zero-age main sequence, through thermally pulsing and mass-loss phases, ending as the white dwarfs at the cooling sequence. Our simulations are full evolutionary, in which we consider the entire evolutionary history of the progenitors. We present reliable nuclear chemical profiles for the whole mass range considered, covering the different expected central compositions, i.e. C/O, O/Ne and Ne/O/Mg, and their dependence with the stellar mass. In addition, we present detailed chemical profiles of hybrid C/O-O/Ne core white dwarfs, found in the mass range between 1.024 and 1.150 M . We present the initial-to-final mass relation, mass-radius relation, and cooling times with improved crystallization limits, considering the effects of atmosphere and core composition.pt_BR
dc.format.mimetypeapplication/pdfpt_BR
dc.language.isoengpt_BR
dc.rightsOpen Accessen
dc.subjectStar evolutionen
dc.subjectAnãs brancaspt_BR
dc.subjectEvolucao estelarpt_BR
dc.subjectNumerical methodsen
dc.subjectMétodos numéricospt_BR
dc.subjectWhite dwarfen
dc.titleEvolutionary sequences for H and He atmosphere massive white dwarf starspt_BR
dc.title.alternativeSequências evolucionárias de estrelas anãs brancas massivas com atmosfera de H e He pt
dc.typeDissertaçãopt_BR
dc.contributor.advisor-coKepler, Souza Oliveirapt_BR
dc.identifier.nrb001072823pt_BR
dc.degree.grantorUniversidade Federal do Rio Grande do Sulpt_BR
dc.degree.departmentInstituto de Físicapt_BR
dc.degree.programPrograma de Pós-Graduação em Físicapt_BR
dc.degree.localPorto Alegre, BR-RSpt_BR
dc.degree.date2018pt_BR
dc.degree.levelmestradopt_BR


Thumbnail
   

Este item está licenciado na Creative Commons License

Mostrar registro simples