Explaining the decrease in ISM lithium at super-solar metallicities in the solar vicinity
Journal
Date Issued
2019
Author(s)
Guiglion, G.
•
Chiappini, C.
•
•
Matteucci, F.
•
Anders, F.
•
Steinmetz, M.
•
Minchev, I.
•
de Laverny, P.
•
Recio-Blanco, A.
Abstract
We propose here that the lithium decrease at super-solar metallicities
observed in high resolution spectroscopic surveys can be explained by the
interplay of mixed populations, coming from the inner regions of the Milky Way
disc. The lower lithium content of these stars is a consequence of inside-out
disc formation, plus radial migration. In this framework, local stars with
super-solar metallicities would have migrated to the solar vicinity and
depleted their original lithium during their travel time. To arrive to such a
result, we took advantage of the AMBRE catalog of lithium abundances combined
with chemical evolution models which take into account the contribution to the
lithium enrichment by different nucleosynthetic sources. A large proportion of
migrated stars can explain the observed lower lithium abundance at super-solar
metallicities. We stress that nowadays, there is no stellar model able to
predict Li-depletion for such super-solar metallicity stars, and the Solar
Li-depletion has to be assumed. In addition, it currently exists no solid
quantitative estimate of the proportion of migrated stars in the Solar
neighborhood and their travel time. Our results illustrate how important it is
to properly include radial migration when comparing chemical evolution models
to observations, and that in this case, the lithium decrease at larger
metallicities does not necessarily imply that stellar yields have to be
modified, contrary to previous claims in literature.
Volume
623
Start page
A99
Issn Identifier
0004-6361
Ads BibCode
2019A&A...623A..99G
Rights
open.access
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