The evolution and C, N and O yields of intermediate-mass Z = 10 -5 stars in isolation and in close binary systems

P. Gil-Pons, C. L. Doherty, Takuma Suda, S. W. Campbell, H. Lau, S. M. Guilani, J. C. Lattanzio

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearch

Abstract

We have computed the evolution of Z=10-5 stars of masses between 4 and 9 M, from their main sequence till the late TP-(S)AGB phase. We use a recent Monash version of the Mount Stromlo Stellar Evolution code, in which molecular opacities include the effects of variable C=O abundances ratio, [1]. By computing hundreds (or thousands) of thermal pulses, we have been able either to remove the bulk of the stellar envelopes or to obtain stellar cores very close to MCh. Using [2] prescription for the mass loss rates the computed stars lose their envelopes before their cores reach MCh. This would prevent the occurrence of SN 1.5 for Z=10-5 stars. Nevertheless the results by [3] suggest that the former prescription might overestimate the mass-loss rates. Therefore we have decreased the rates by [2]. For all the cases we present, even a decrease of one order of magnitude let the stellar cores reach MCh before the envelope is lost. Therefore the occurrence of SN1.5 at Z=10-5 and their potential contribution to the chemical evolution of the Universe should not be discarded. We consider the combined effects of the deep/corrosive 2nd dredge-up and Roche Lobe Overflow (RLOF) during the E-AGB to help to constrain the contribution of massive Z=10-5 AGB stars to the CEMPs problem. Our results have implications for the chemical evolution of the Universe and might provide another piece for the puzzle of the CEMPs problem.

Original languageEnglish
Title of host publicationFirst Stars IV - From Hayashi to the Future
Subtitle of host publicationKyoto, Japan; 21-25 May 2012
EditorsMasayuki Umemura, Kazuyuki Omukai
Place of PublicationUSA
PublisherAIP Publishing
Pages358-360
Number of pages3
ISBN (Print)9780735410923
DOIs
Publication statusPublished - 2012
EventConference on FIRST STARS - From Hayashi to the Future 2012 - Kyoto, Japan
Duration: 21 May 201225 May 2012
Conference number: 4th

Publication series

NameAIP Conference Proceedings
PublisherAIP Publishing
Volume1480
ISSN (Print)0094-243x

Conference

ConferenceConference on FIRST STARS - From Hayashi to the Future 2012
CountryJapan
CityKyoto
Period21/05/1225/05/12

Keywords

  • AGB stars
  • binary evolution
  • Stellar evolution

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