A Process in Search of an Environment: The \(r\)-Process

  • Giora Shaviv
Part of the Astrophysics and Space Science Library book series (ASSL, volume 387)


While the \(s\)-process can be described as a low neutron flux occurring over a long period of time, the \(r\)-process can be described as the opposite, namely, irradiation by a high neutron flux for a very short time. Hence, while the \(s\)-process could be described as a quiet, slow, hydrostatic evolution, the \(r\)-process is usually associated with the most violent phases in stellar life—the explosion that puts an end to the ‘normal’ life of the star. It seems that no in-between process exists, only the two extremes. Notwithstanding, problems with the explosion scenario have led astrophysicists to ponder on less violent circumstances where a milder variant of the \(r\)-process might take place. But whatever the situation, we are now looking for an extreme source of neutrons in an expanding environment. The adjective ‘extreme’ refers to the nuclear properties while the requirement of expansion refers to the astrophysical site, so that the synthesized isotopes can be ejected into space. Alpher, Bethe, and Gamow considered the Big Bang to be just such an explosive situation, but in this specific case we are supposedly immersed in the products.


Solar System Neutron Star Process Element Magic Number Halo Nucleus 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Giora Shaviv
    • 1
  1. 1.Department of PhysicsTechnion-Israel Institute of TechnologyHaifaIsrael

Personalised recommendations