Stellar evolution

Stellar evolution is the field of astronomy that describes the theoretic changes that stars are believed to undergo during their life cycle, including star formation. Since these changes are believed to occur over millions or even billions of years, astrophysicists theorize about how stars evolve by observing numerous stars, each at a different point in its life cycle, and simulating stellar structure with computer models.

Operational Science and Stellar Evolution

 * Star formation: All naturalistic models of star birth which have been proposed thus far violate basic laws of physics and chemistry.
 * Solar system formation: The nebula hypothesis is the most generally accepted evolutionary model for formation of the solar system.
 * Big Bang cosmology: The main theory used to explain the origin of the Universe is a highly energetic explosion.



Testing stellar evolution is very difficult since the interiors of stars cannot be seen. It would take an exceedingly long time to watch individual stars go through these cycles. Many stars are used to determine the sequences. Furthermore, supernovas producing neutron stars are the only observed star changes associated with stellar evolution. This does not prove that any other changes occur.



H-R Diagram
The H-R Diagram is a plot of a star's temperature and luminosity. It is a useful tool in comparing stars.

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Related References

 * Stellar Evolution by Wikipedia
 * The age of theuniverse by David N. Spergel, Michael Bolte and Wendy Freedman for The National Academy of Sciences of the USA

Évolution stellaire