Stellar Systems
Mostrando 13-23 de 23 artigos, teses e dissertações.
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13. Populações estelares em galáxias elípticas: cinemática e indicadores de metalicidade e idade / Stellar populations on elliptical galaxies: kinematic, metallicity and age indicators
O estudo da distribuição interna das populações estelares em galáxias do tipo prematuro fornecem informações fundamentais para testar os seus modelos de formação e evolução químio-dinâmica. Por outro lado, o estudo da dinâmica estelar interna nessas galáxias fornece informações relevantes para prever a forma: esferóide triaxial, oblato ou p
Publicado em: 2002
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14. Prospectivas de imageamento de sistemas DLA a partir de técnicas de síntese espectral de galáxias / Study of the spectra composed by qso s and DLA s
Hoje em dia, a formação das galáxias não está totalmente compreendida. Acredita-se que foram formadas a partir de nuvens de alta densidade de hidrogênio neutro, com diferentes graus de metalicidade. Estas nuvens acham-se em maior número em redshifts (z)altos (2 - 4.5). Devido a suas baixas luminosidades, é difícil descobrí-las, de forma isolada. Na
Publicado em: 2002
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15. Investigações sobre as relações de escala dos sistemas estelares auto-gravitantes / Investigations on the scaling relations of self-gravitating stellar systems
We aim in this work to collect several numerical and analitical investigations concerning the origin of the scaling relations of the self-gravitating stellar systems. These relations depend on a very small number of independent physical parameters that reduce and confine the observational constraints to a plane in this parameter space, called the ""Fundament
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 200105
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16. Investigations on the scaling relations of self-gravitating stellar systems / Investigações sobre as relações de escala dos sistemas estelares auto-gravitantes
We aim in this work to collect several numerical and analitical investigations concerning the origin of the scaling relations of the self-gravitating stellar systems. These relations depend on a very small number of independent physical parameters that reduce and confine the observational constraints to a plane in this parameter space, called the ""Fundament
Publicado em: 2001
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17. Investigações sobre as relações de escala dos sistemas estelares auto-gravitantes / Investigations on the scaling relations of self-gravitating stellar systems
Objetivamos neste trabalho reunir algumas investigações de ordem numérica e analítica sobre a origem das relações de escala dos sistemas estelares auto-gravitantes. Estas relações dependem de um número bastante pequeno de parâmetros físicos independentes, que reduzem e confinam os vínculos observacionais a um plano neste espaço de parâmetros, c
Publicado em: 2001
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18. Cordas cosmicas e vortices em relatividade geral : pertubações radiais de soluções estaticas e estacionarias
A linearized theory of the dynamics of small perturbations of certain cylindrically symmetric systems in general relativity is presented. Firstly, we deal with straight, static cosmic strings of finite thickness in the U(l) gauge theory coupled to the Einstein equations. Taking into account the asymptotic behavior of the solution and certain integral ide
Publicado em: 1994
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19. Stability in dynamical astronomy*
Hill's concept of stability is generalized and its relation to bifurcation theory is shown. A quantitative measure of stability is introduced that allows the comparison of the stability of different astronomical systems. Theoretical stability limits for triple stellar systems, for planetary systems, and for satellite systems are established. The measure of s
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20. Formation of Binaries from Triple Systems
The dynamical behavior of three masses moving under their mutual gravitational attraction in a plane is investigated by a systematic series of numerical experiments. It is shown that in 73% of the cases, a triple system disintegrates in less than 150 time units (corresponding to about 150 crossing times), and a binary is formed with the third star that escap
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21. Model nebulae and determination of the chemical composition of the Magellanic Clouds
An analysis of previously presented photoelectric spectrophotometry of HII regions (emission-line diffuse nebulae) in the two Magellanic Clouds is carried out with the aid of theoretical nebular models, which are used primarily as interpolation devices. Some advantages and limitations of such theoretical models are discussed. A comparison of the finally obta
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22. Charged-coupled detector sky surveys.
Sky surveys have played a fundamental role in advancing our understanding of the cosmos. The current pictures of stellar evolution and structure and kinematics of our Galaxy were made possible by the extensive photographic and spectrographic programs performed in the early part of the 20th century. The Palomar Sky Survey, completed in the 1950s, is still the
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23. Galaxy dynamics and the mass density of the universe.
Dynamical evidence accumulated over the past 20 years has convinced astronomers that luminous matter in a spiral galaxy constitutes no more than 10% of the mass of a galaxy. An additional 90% is inferred by its gravitational effect on luminous material. Here I review recent observations concerning the distribution of luminous and nonluminous matter in the Mi