Feb 7 – 9, 2017
Radisson Hotel Lansing
US/Eastern timezone

A Novel Pre-supernova Pop III Stellar Evolution and Nucleosynthesis Scenario for the most Fe-deficient star (Keller star)

Feb 8, 2017, 2:00 PM
15m
Radisson Hotel Lansing

Radisson Hotel Lansing

111 N Grand Ave, Lansing, MI 48933
Talk [Main Conference] Contributed talk Session 7

Speaker

Ms Ondrea Clarkson (University of Victoria)

Description

H-ingestion events in low metallicity and Pop III stars have been reported previously, but have not yet been investigated in any detail. In order to explain the most iron-poor star found to date, the Keller star (SMSS J031300.362670839.3), we propose a scenario based on stellar evolution simulations in which a 45Msun Pop III star experiences H-ingestion into the convective He-shell burning shell. During the H-ingestion stellar evolution models predict an energy release of log(Lnuc) = 12.8, or >10% of the mixed layer's internal energy. event the dynamic response of the convection zone must be ultimately investigated with 3D hydrodynamical simulations, which is a future goal. In the meantime, we follow a likely nucleosynthesis scenario associated with H-ingestion events using the NuGrid single-zone nucleosynthesis code PPN. The H-ingestion triggers light-element i-process nucleosynthesis on C12 as a seed. The assumption that the i-process enriched layer is partially ejected and diluted with unprocessed envelope material at a ratio of approximately 1:100 results in an abundance distributions that unmistakably reproduce that of of the Keller star, and suggest possible implications for the early chemical enrichment. Remaining discrepancies of our scenario prediction and observations can originate in the approximate nature of the astrophysics modeling, or in uncertainties of nuclear physics of the many unstable species involved in the reaction path.

Primary author

Ms Ondrea Clarkson (University of Victoria)

Co-author

Prof. Falk Herwig (University of Victoria)

Presentation materials

There are no materials yet.