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Previous issue date: 2015-12-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A rota??o ? um dos mais importantes observ?veis em astronomia estelar, conduz
a forma??o e evolu??o das estrelas. De fato, a principal meta desafiadora no
estudo da rota??o estelar ? a compreens?o da hist?ria do momento angular, uma
vez que as estrelas evoluem ao longo do diagrama HR, bem como o papel da rota??o
em diferentes fen?menos din?micos, incluindo a atividade magn?tica estelar,
processos de acre??o e coalesc?ncia. O presente trabalho traz a an?lise sem precedentes
da rota??o ao longo do diagrama HR, com base em uma amostra completa
de estrelas evolu?das de classe de luminosidade Ib, II, III e IV, respectivamente as
supergigantes Ib, gigantes brilhantes, gigantes e subgigantes. Para o estudo rotacional,
n?s usamos a velocidade de rota??o projetada, v sen i, calculada a partir de
observa??es feita com o espectr?metro CORAVEL (Baranne et al., 1979) e apresentadas
em diferentes cat?logos (De Medeiros e Mayor (1999); De Medeiros et
al. (2002) e De Medeiros et al. (2014)). Pela primeira vez um estudo da evolu??o
da rota??o ? apresentada por estrelas individuais e m?ltiplas. Confirmamos que a
rota??o de estrelas individuais diminui acentuadamente a partir de tipo espectral
F e G, dependendo da classe de luminosidade e da massa estelar. A partir das
regi?es espectrais G e K, a rota??o diminui para todas as classes de luminosidade.
O presente estudo revela tamb?m o aumento da rota??o estelar devido a sincroniza??o,
resultado dos efeitos de mar?s, em sistemas bin?rios com componentes
evolu?das. Para todas as classes de luminosidade analisada detectamos rota??o
nas regi?es espectrais F, G e K com valores de at? 70 km/s. / Rotation is one of the most important observable in stellar astronomy, driving
largely the formation and evolution of stars. Indeed, the main challenging goal
in the study of stellar rotation is the understanding of the angular momentum
history once stars evolve along the HR diagram, as well the role of rotation in
different dynamical phenomena including the stellar magnetic activity, accretion
and coalescence processes. The present work brings unprecedented analysis of
rotation along the HR diagram, on the basis of a complete sample of evolved
stars, namely stars of luminosity classes Ib, II, III and IV, respectively supergiants,
bright giants, giants and subgiants. For the rotational diagnostic, we use
projected rotational velocity computed from observations carried out with of the
CORAVEL spectrometers (Baranne et al. 1979) and presented in different catalogs
(De Medeiros and Mayor (1999); De Medeiros et al. (2002) and De Medeiros
et al. (2014). For the first time an evolutionary study of rotation is presented for
single and multiple stars. We confirm that the rotation of single stars decrease
sharply from spectral type F to G, at a rate depending on luminosity class and
stellar mass. From G to K spectral regions rotation decreases smoothly for both
luminosity classes. The present study reveals also the extent of the effects of tidal
synchronization on stellar rotation, in binary systems with evolved components.
For all the analysed luminosity classes we detect enhanced rotation in the G and
K spectral regions, with values up to 70 km/s.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21586 |
| Date | 21 December 2015 |
| Creators | Oliveira, Luciano Luiz Alencar de |
| Contributors | 08896135400, http://lattes.cnpq.br/9151590034650501, Martins, Bruno Leonardo Canto, 96670193491, http://lattes.cnpq.br/2673267660389058, Miranda, Antonio Carlos da Silva, 12857645449, http://lattes.cnpq.br/3236324734090101, Medeiros, Jos? Renan de |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM F?SICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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