The uncertainties in the [superscript 22]Ne+[alpha]-capture reaction rates and the production of the heavy magnesium isotopes in asymptotic giant branch stars of intermediate mass

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dc.creator Karakas, A. I.
dc.creator Lugaro, M. A.
dc.creator Wiescher, M.
dc.creator Gorres, J.
dc.creator Ugalde, C.
dc.date.accessioned 2015-03-11T16:01:33Z
dc.date.available 2015-03-11T16:01:33Z
dc.date.issued 2006-05-20
dc.identifier.issn 0004-637X
dc.identifier.uri http://library2.smu.ca/xmlui/handle/01/25985
dc.description Publisher's version/PDF en_CA
dc.description.abstract We present new rates for the [superscript 22]Ne([alpha], n)[superscript 25]Mg and [superscript 22]Ne([alpha], [gamma])[superscript 26]Mg reactions, with uncertainties that have been considerably reduced compared to previous estimates, and we study how these new rates affect the production of the heavy magnesium isotopes in models of intermediate-mass asymptotic giant branch (AGB) stars of different initial compositions. All the models have deep third dredge-up, hot bottom burning, and mass loss. Calculations have been performed using the two most commonly used estimates of the [superscript 22]Ne+[alpha] rates as well as the new recommended rates, and with combinations of their upper and lower limits. The main result of the present study is that, with the new rates, uncertainties on the production of isotopes from Mg to P coming from the [superscript 22]Ne+[alpha]-capture rates have been considerably reduced.We have therefore removed one of the important sources of uncertainty to effect models of AGB stars. We have studied the effects of varying the mass-loss rate on nucleosynthesis and discuss other uncertainties related to the physics employed in the computation of stellar structure, such as the modeling of convection, the inclusion of a partial mixing zone, and the definition of convective borders. These uncertainties are found to be much larger than those coming from [superscript 22]Ne+[alpha]-capture rates, when using our new estimates. Much effort is needed to improve the situation for AGB models. en_CA
dc.language.iso en en_CA
dc.publisher American Astronomical Society en_CA
dc.relation.uri http://dx.doi.org/10.1086/502793
dc.rights Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
dc.subject.lcsh Nuclear reactions
dc.subject.lcsh Asymptotic giant branch stars
dc.subject.lcsh Nucleosynthesis
dc.subject.lcsh Cosmic abundances
dc.subject.lcsh Stars -- Evolution
dc.subject.lcsh Stars -- Structure
dc.title The uncertainties in the [superscript 22]Ne+[alpha]-capture reaction rates and the production of the heavy magnesium isotopes in asymptotic giant branch stars of intermediate mass en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Astrophysical Journal 643(1), 471-483. (2006) en_CA


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Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
 
Published Version: http://dx.doi.org/10.1086/502793
 
 

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