i-process nucleosynthesis: observational evidences from CEMP stars
arXiv:2011.02419 · doi:10.1007/s12036-020-09670-7
Abstract
The surface chemical compositions of a large fraction of Carbon-Enhanced Metal-Poor (CEMP) stars, the so-called CEMP-r/s stars, are known to exhibit enhancement of both s- and r-process elements. For these stars, the heavy element abundances cannot be explained either by s-process or r-process nucleosynthesis alone, as the production sites of s- and r-process elements are very different, and these two processes produce distinct abundance patterns. Thus, the observational evidence of the double enhancement seen in CEMP-r/s stars remains a puzzle as far as the origin of the elements is concerned. In this work, we have critically analysed the observed abundances of heavy elements in a sample of eight CEMP-r/s stars from literature, to trace the origin of the observed double enhancement. Towards this, we have conducted a parametric-model based analysis to delineate the contributions of s- and r-process nucleosynthesis to the observed elemental abundances. We have further examined if the i-process (intermediate process) nucleosynthesis, that occurs at a high neutron-density (n10 cm ) produced during proton-ingestion from a H-rich envelope to the intershell region of an AGB star, that is capable of producing both r- and s-process elements in a single stellar site, could explain the observed abundance patterns of the sample stars. Our analysis shows that the observed abundance patterns of the selected sample of CEMP-r/s stars could be fairly well reproduced using the i-process model yields.
8 pages, 2 figures, accepted for publication in Journal of Astrophysics and Astronomy (JAA)
References in corpus (27)
- Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
- Nucleosynthesis in neutrino-driven winds: I. The physical conditions
- Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
- Super and massive AGB stars - IV. Final fates - Initial to final mass relation
- The s-Process in Low Metallicity Stars. II. Interpretation of High-Resolution Spectroscopic Observations with AGB models
- The intermediate neutron-capture process and carbon-enhanced metal-poor stars
- Galactic evolution of rapid neutron capture process abundances: the inhomogeneous approach
- The Hamburg/ESO R-process Enhanced Star survey (HERES) III. HE 0338-3945 and the formation of the r+s stars
- Abundance Analysis of HE2148-1247, A Star With Extremely Enhanced Neutron Capture Elements
- s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models
- H ingestion into He-burning convection zones in super-AGB stellar models as a potential site for intermediate neutron-density nucleosynthesis
- Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes
- Elemental abundances and classification of CEMP stars
- 3D hydrodynamical simulations of a proton ingestion episode in a low-metallicity asymptotic giant branch star
- Stellar Sources for Heavy r-Process Nuclei
- A high-resolution spectral analysis of three carbon-enhanced metal-poor stars
- Observational evidence for a different IMF in the early Galaxy
- Low-mass supernovae in the early Galactic halo: source of the double r/s-process enriched halo stars?
- Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. I. Detailed analysis of 15 binary stars with known orbital periods
- Abundances and kinematics of carbon-enhanced metal-poor stars in the Galactic halo*; A new classification scheme based on Sr and Ba
- Learning about the intermediate neutron-capture process from lead abundances
- How plausible are the proposed formation scenarios of CEMP-r/s stars?
- Chemical analysis of CH stars - III: Atmospheric parameters and elemental abundances
- An Explosive End to Intermediate-Mass Zero-Metallicity Stars and Early Universe Nucleosynthesis
- Diversity of Abundance Patterns of Light Neutron-capture Elements in Very-metal-poor Stars
- Radiative levitation in carbon-enhanced metal-poor stars with s-process enrichment
- High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: II. Binary Fraction