Investigation for the enrichment pattern of the element abundances in r+s star HE 0338-3945: a special r-II star?

Abstract

The very metal-poor star HE 0338-3945 shows a double-enhanced pattern of the neutron-capture elements. The study to this sample could make people gain a better understanding of s- and r-process nucleosynthesis at low metallicity. Using a parametric model,we find that the abundance pattern of the neutron-capture elements could be best explained by a binary system formed in a molecular cloud, which had been polluted by r-process material. The observed abundance pattern of C and N can be explained by an AGB model(Karakas & Lattanzio 2007), . Combing with the parameters obtained from Cui & Zhang (2006), we suggest that the initial mass of the AGB companion is most likely to be about 2.5Msun, which excludes the possibility of forming a type-1.5 supernova. By comparing with the observational abundance pattern of CS 22892-052, we find that the dominating production of O should accompany with the production of the heavy r-process elements of r+s stars. Similar to r-II stars, the heavy r-process elements are not produced in conjunction with all the light elements from Na to Fe group. The abundance pattern of the light and r-process elements for HE 0338-3945 is very close to the pattern of the r-II star CS 22892-052. So, we suggest that this star HE 0338-3945 should be a special r-II star.

arXiv comment18 pages, 6 figures, published by ApJ

References in corpus (24)

• Neutron capture in low mass Asymptotic Giant Branch stars: cross sections and abundance signatures
• The Extremely Metal-Poor, Neutron-Capture-Rich Star CS 22892-052: A Comprehensive Abundance Analysis
• The extreme r-element rich, iron-poor halo giant CS31082-001: Implications for the r-process site(s) and radioactive cosmochronology
• Measurement of stellar age from uranium decay
• Where, oh where has the r-process gone?
• Stellar Models and Yields of Asymptotic Giant Branch Stars
• s Process in low-mass Asymptotic Giant Branch Stars
• Evidence of Multiple r-Process Sites in the Early Galaxy: New Observations of CS 22892-052
• R-Process Abundances and Chronometers in Metal-Poor Stars
• A Subaru/HDS study of Lead (Pb) abundances in eight s-process-element-rich, metal-poor stars
• The Hamburg/ESO R-process Enhanced Star survey (HERES) III. HE 0338-3945 and the formation of the r+s stars
• Neutron Capture Elements in s-Process-Rich, Very Metal-Poor Stars
• On OH line formation and oxygen abundances in metal-poor stars
• Abundance Analysis of HE2148-1247, A Star With Extremely Enhanced Neutron Capture Elements
• The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars
• CS 30322-023: an ultra metal-poor TP-AGB star?
• New analysis of the two carbon-rich stars CS 22948-27 and CS 29497-34 : binarity and neutron-capture elements
• Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes
• Stellar Sources for Heavy r-Process Nuclei
• Low-mass supernovae in the early Galactic halo: source of the double r/s-process enriched halo stars?
• A Simple Model for r-Process Scatter and Halo Evolution
• Neutron-capture elements in the s- and r-process-rich stars: Constraints on neutron-capture nucleosynthesis processes
• The origin of the lead-rich stars in Galactic halo: investigation of the model parameters for the s-process
• Investigation for the puzzling abundance pattern of the neutron-capture elements in the ultra metal-poor star: CS 30322-023

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• The Hamburg/ESO R-process Enhanced Star survey (HERES) VIII. The r+s star HE 1405 0822
• Abundances of neutron-capture elements in G 24-25. A halo-population CH subgiant
• Possible discovery of the r-process characteristics in the abundances of metal-rich barium stars
• The odd-isotope fractions of Barium in CEMP-r/s star HE 0338-3945 and r-II star CS 31082-001
• The study of s-process nucleosynthesis based on barium stars, CEMP-s and CEMP-r/s stars