Neutron stars history

Abundance results for additional clusters are currently underway and include analyses of the neutron-capture elements (in order to trace the onset of contributions from low-mass Type II SNe as well as AGB stars). Combined with their ages, the nucleosynthetic histories of the outer halo clusters will better constrain the timescales of formation and construction of the Galaxy. 

Variations in star formation history should be imprinted on the s- and r-process ratios as well, however their interpretation can be more complicated because of uncertainties in their exact sources (and thus yields). Y and Ba trace the first and second peak in neutron magic number, respectively, and can be used to examine r-process yields in very metal-poor stars. However, they also have a significant contribution from the s-process in AGB stars, which dominates their production with increasing metallicity. Since AGB s-process yields are thought... 

In the present state of the universe, only a very small part of the energy is in the form of protons, neutrons and electrons that make up ordinary matter in all the galaxies. The rest consists of thermal radiation at a temperature of about 2.8 K and particles called neutrinos that interact very weakly with other particles. The small amount of matter which is in the form of stars and galaxies, however, is not in thermodynamic equilibrium. The affinities for the reactions that are currently occurring in the stars are not zero. The nuclear reactions in the stars produce all the known elements from hydrogen [2-4]. Hence the observed properties such as the abundance of elements in stars and planets cannot be described using the theory of chemical equilibrium. A knowledge of the rates of reaction and the history of the star or planet are necessary to understand the abundance of elements. 

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