The Production of the Elements C through AL in Globular Cluster Red Giant Stars

Details The Production of the Elements C through AL in Globular Cluster Red Giant Stars The Production of the Elements C through AL in Globular Cluster Red Giant Stars

Dec 1996

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996aas...189.7809c&link_type=abstract

American Astronomical Society, 189th AAS Meeting, #78.09; Bulletin of the American Astronomical Society, Vol. 28, p.1378

Astronomy and Astrophysics

Astronomy

Scientific paper

Observations of red giants within some globular clusters show star-to-star abundance variations of the elements from C to Al. Since many of these variations depend on luminosity, they must arise during the evolution of these stars. Furthermore, the extent of the variations seems to depend on the cluster metallicity, with the more metal-poor clusters showing large variations in elements up to Al, while the more metal-rich clusters show smaller variations only up to Na. We explore this discrepancy by following the production of the elements C through Al in realistic red giant branch (RGB) sequences of differing metallicities. This project is designed as a two-step process, one which examines the distribution of these elements around the H-burning shell, followed by one which incorporates the abundance profiles into a mixing algorithm for comparison to the observations. The first step, reported here, combines a detailed nuclear reaction network with the RGB sequences so that we may examine the distribution of elements around the H shell while allowing for the variation of the temperature and density around the shell, and accounting for the change in the structure of the shell with evolution. The reaction rates are varied according their published uncertainties to explore their effects on the final abundance distribution. We find that we can qualitatively reproduce the the observations of the CNO, NeNa, and MgAl cycle elements in our sequences. As a result of their higher temperatures, longer burning times, and thicker shells, the lower metallicity sequences show variations in all the elements through Al while the higher metallicity sequences exhibit variations only in the CNO and NeNa elements, in accord with the observations. We find, however, that the (24) Mg proton-capture rate must be increased beyond what is presently allowed by the nuclear uncertainties in order to match the observed (24) Mg abundances in M13.

Affiliated with

Also associated with

No associations

Rating

The Production of the Elements C through AL in Globular Cluster Red Giant Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Production of the Elements C through AL in Globular Cluster Red Giant Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Production of the Elements C through AL in Globular Cluster Red Giant Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-817838