Evolution of lithium in the Milky Way halo, discs and bulge
Date Issued
2019
Author(s)
Abstract
In this work, we study the Galactic evolution of lithium by means of chemical
evolution models in the light of the most recent spectroscopic data from
Galactic stellar surveys. We consider detailed chemical evolution models for
the Milky Way halo, discs and bulge, and we compare our model predictions with
the most recent spectroscopic data for these different Galactic components. In
particular, we focus on the decrease of lithium at high metallicity observed by
the AMBRE Project, the Gaia-ESO Survey, and other spectroscopic surveys, which
still remains unexplained by theoretical models. We analyse the various lithium
producers and confirm that novae are the main source of lithium in the Galaxy,
in agreement with other previous studies. Moreover, we show that, by assuming
that the fraction of binary systems giving rise to novae is lower at higher
metallicity, we can suggest a novel explanation to the lithium decline at
super-solar metallicities: the above assumption is based on independent
constraints on the nova system birthrate, that have been recently proposed in
the literature. As regards to the thick disc, it is less lithium enhanced due
to the shorter timescale of formation and higher star formation efficiency with
respect to the thin disc and, therefore, we have a faster evolution and the
"reverse knee" in the A(Li) vs. [Fe/H] relation is shifted towards higher
metallicities. Finally, we present our predictions about lithium evolution in
the Galactic bulge, that, however, still need further data to be confirmed or
disproved.
Volume
489
Issue
3
Start page
3539
Issn Identifier
0035-8711
Ads BibCode
2019MNRAS.489.3539G
Rights
open.access
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