Pop III i-process nucleosynthesis and the elemental abundances of SMSS J0313-6708 and the most iron-poor stars

Clarkson, O.; Herwig, F.; Pignatari, M.

Abstract

© 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. We have investigated a highly energetic H-ingestion event during shell He burning leading to H-burning luminosities of log (L H /L ⊙ ) ~ 13 in a 45M⊙ Pop III massive stellar model. In order to track the nucleosynthesis which may occur in such an event, we run a series of single-zone nucleosynthesis models for typical conditions found in the stellar evolution model. Such nucleosynthesis conditions may lead to i-process neutron densities of up to ~10 13 cm -3 . The resulting simulation abundance pattern, where Mg comes from He burning and Ca from the i process, agrees with the general observed pattern of the most iron-poor star currently known, SMSS J031300.36-670839.3. However, Na is also efficiently produced in these i-process conditions, and the prediction exceeds observations by ~2.5 dex. While this probably rules out this model for SMSS J031300.36-670839.3, the typical i-process signature of combined He burning and i process of higher than solar [Na/Mg] , [Mg/Al], and low [Ca/Mg] is reproducing abundance features of the two next most iron-poor stars HE 1017-5240 and HE 1327-2326 very well. The i process does not reach Fe which would have to come from a low level of additional enrichment. i process in hyper-metal-poor or Pop III massive stars may be able to explain certain abundance patterns observed in some of the most metal-poor CEMP-no stars.

Citation

Clarkson, O., Herwig, F., & Pignatari, M. (2018). Pop III i-process nucleosynthesis and the elemental abundances of SMSS J0313-6708 and the most iron-poor stars. Monthly notices of the Royal Astronomical Society. Letters, 474(1), L37-L41. https://doi.org/10.1093/mnrasl/slx190

• Journal Article Type: Article
• Acceptance Date: Nov 21, 2017
• Online Publication Date: Nov 23, 2017
• Publication Date: Feb 11, 2018
• Deposit Date: Mar 18, 2018
• Publicly Available Date: Oct 27, 2022
• Journal: MNRAS
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 474
• Issue: 1
• Pages: L37-L41
• DOI: https://doi.org/10.1093/mnrasl/slx190
• Keywords: Nuclear reactions; Nucleosynthesis; Abundances; Stars: carbon; Stars: Population III
• Public URL: https://hull-repository.worktribe.com/output/586987
• Publisher URL: https://academic.oup.com/mnrasl/article/474/1/L37/4655185
• Related Public URLs: https://arxiv.org/abs/1710.01763
• Additional Information: This article has been accepted for publication in MNRAS ©: 2017 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
• Contract Date: Mar 18, 2018