The smaller supply of neutrons found in the helium shell of bloated, elderly stars known as asymptotic giant branch
stars prompts "slow" capture, in which atoms absorb neutrons at a slower rate.
First, the team compiled information about the masses, luminosities, and such for stars of different ages, focusing especially on asymptotic giant branch
Abstract: Planetary Nebulae represent a powerful window into the evolution of low-intermediate mass stars that have undergone extensive mass-loss on the asymptotic giant branch
. The nebula manifests itself in an extremely wide variety of shapes, but exactly how nebulae are shaped into such a diverse range of morphologies is still highly uncertain despite over thirty years of vigorous debate.
The type of companion called for in this picture is an evolved red giant known as an asymptotic giant branch
, or AGB, star.
The conditions are just right in the atmospheres of cool, aged stars--red giants and stars on the asymptotic giant branch
of the Hertzsprung-Russell diagram, which charts the stages of stellar evolution (S&T: March 1999, page 43).
The responsible party is a so-called asymptotic giant branch
star, which powers itself by two fusion reactions.