Neutron source, neutron density and the origin of barium stars.
Abstract
The authors present new high resolution spectra of the MgH profiles in nine barium stars, and determine, by spectral synthesis techniques, the magnesium isotopic ratios in each star. When compared with recent AGB nucleosynthesis calculations, they can emphatically rule out the operation of the 22Ne(α, n)25Mg reaction as the neutron source responsible for the s-process enhancements observed in these barium stars. The authors identify the properties required of future AGB stellar models if the much favoured origin for the barium stars, namely an AGB mass transfer scenario, is to be made consistent with the observations reported here. Alternative evolutionary origins of the barium stars are discussed.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1988
- DOI:
- 10.1093/mnras/235.3.695
- Bibcode:
- 1988MNRAS.235..695M
- Keywords:
-
- Barium;
- Metallicity;
- Neutron Stars;
- Nuclear Astrophysics;
- Stellar Evolution;
- Stellar Models;
- Abundance;
- Asymptotic Giant Branch Stars;
- Degenerate Matter;
- Nuclear Fusion;
- Astrophysics