1999/06/15 by Y. -Z. Qian, Y.‐Z. Qian, G. J. Wasserburg · 3 citations
Physics and Astronomy · #Abundance (ecology) #Astro and Planetary Science #Astronomy #Astrophysics #Galaxy #Gamma-ray bursts and supernovae #Nucleosynthesis #Physics #Solar mass #Stars #Stellar, planetary, and galactic studies #Supernova #astro-ph #r-process
paper · pdf · doi:10.1016/s0370-1573(00)00017-x
published as Phys.Rept. 333 (2000) 77-108 · 46 pages, 19 figures, to appear in the Schramm Memorial Volume of Physics Reports
arxiv created 1999/06/15 · openalex publication_date 2000/08/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present quantitative predictions for the abundances of r-process elements in stars formed very early in the Galactic history using a phenomenological two-component r-process model based on the I129 and Hf182 inventory in the early solar system. This model assumes that a standard mass of the ISM dilutes the debris from an individual supernova. High frequency supernova H events and low frequency supernova L events are proposed in the model with characteristics determined by the meteoritic data on I129 and Hf182. The yields in an H or L event are obtained from these characteristics and the solar r-process abundances under the assumption that the yield template for the high mass (A > 130) nuclei associated with W182 or the low mass (A < or = 130) nuclei associated with I127 is the same for both the H and L events and follows the corresponding solar r-pattern in each mass region. The abundance of Eu, not Fe, is proposed as a key guide to the age of very metal-poor stars. We predict that stars with log epsilon (Eu) = -2.98 to -2.22 were formed from an ISM contaminated most likely by a single H event within the first 10**7 yr of the Galactic history and should have an Ag/Eu abundance ratio less than the corresponding solar r-process value by a factor of at least 10. Many of the very metal-poor stars observed so far are considered here to have been formed from an ISM contaminated by many (about 10) r-process events. Stars formed from an ISM contaminated only by a pure L event would have an Ag/Eu ratio higher than the corresponding solar r-process value but would be difficult to find due to the low frequency of the L events. However, variations in the relative abundances of the low and high mass regions should be detectable in very metal-poor stars.