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Primordial and pre-galactic origins of the lithium isotopes

Asplund, Martin; Melendez Moreno, Jorge

Description

There are currently two cosmological lithium problems: compared with predictions from Big Bang Nucleosynthesis and models for Galactic cosmic ray production, the observed 7Li abundance in Galactic halo stars is too low while the 6Li content is too high. Here we report on new Keck/HIRES observations of the two extremely metal-poor stars G064-012 and G064-37, which both show distortions of the Li I 670.8 nm line consistent with a significant (≈3σ) presence of 6Li. If confirmed, these are the...[Show more]

dc.contributor.authorAsplund, Martin
dc.contributor.authorMelendez Moreno, Jorge
dc.coverage.spatialSanta Fe, New Mexico, USA
dc.date.accessioned2015-12-10T22:39:27Z
dc.date.created15-20 Jul 2007
dc.identifier.isbn978-0735405097
dc.identifier.urihttp://hdl.handle.net/1885/57181
dc.description.abstractThere are currently two cosmological lithium problems: compared with predictions from Big Bang Nucleosynthesis and models for Galactic cosmic ray production, the observed 7Li abundance in Galactic halo stars is too low while the 6Li content is too high. Here we report on new Keck/HIRES observations of the two extremely metal-poor stars G064-012 and G064-37, which both show distortions of the Li I 670.8 nm line consistent with a significant (≈3σ) presence of 6Li. If confirmed, these are the lowest metallicity 6Li detections and would suggest a cosmological or pre-Galactic origin for the isotope. Invoking stellar Li depletion to solve the above-mentioned 7Li discrepancy would further increase the inferred initial 6Li abundance by a factor of ≈10. Possible 6Li production scenarios are decaying/annihilating supersymmetric particles within the first few minutes of the Big Bang and cosmological cosmic rays from the first stars, although stellar flare production can not be ruled out either. Work still remains, however, before one can unequivocally say that 6Li really has been detected in these and other halo stars, in particular whether convective atmospheric motions and non-LTE line formation can mimic the presence of 6Li in the observed line profiles.
dc.publisherAmerican Institute of Physics (AIP)
dc.relation.ispartofseriesFirst Stars III
dc.sourceFirst Stars III
dc.subjectKeywords: Cosmic ray nucleosynthesis; Galactic halo stars; Origin of the elements. Big Bang nucleosynthesis; Stellar atmospheres; Stellar chemical compositions; Stellar spectroscopy
dc.titlePrimordial and pre-galactic origins of the lithium isotopes
dc.typeConference paper
local.description.notesImported from ARIES
local.description.refereedYes
dc.date.issued2008
local.identifier.absfor020110 - Stellar Astronomy and Planetary Systems
local.identifier.ariespublicationU3488905xPUB390
local.type.statusPublished Version
local.contributor.affiliationAsplund, Martin, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationMelendez Moreno, Jorge, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.startpage342
local.bibliographicCitation.lastpage346
local.identifier.doi10.1063/1.2905578
dc.date.updated2015-12-09T10:51:29Z
local.identifier.scopusID2-s2.0-42449116981
CollectionsANU Research Publications

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