Explaining the decrease in ISM lithium at super-solar metallicities in the solar vicinity

Evolution of lithium in the Milky Way halo, discs, and bulge

“…This feature was first pointed out by Delgado Mena et al (2015), and then confirmed by the AMBRE Project (Guiglion et al 2016), the Gaia-ESO Survey -hereinafter GES- (Fu et al 2018), Bensby & Lind (2018), and can be also seen in the recent GALAH DR2 data (Buder et al 2018). The scenarios proposed to explain this feature from the Galactic Chemical Evolution (GCE) point of view can be summarized as follows: i) lower yields of Li from stars at high metallicities, even if no physical reasons for this fact can be found (Prantzos et al 2017); and ii) the interplay of different populations coming from the inner regions of the Milky Way disc (Guiglion et al 2019, Minchev et al 2019. Here, we propose a new explanation for the lithium ISM decline at high-metallicities, based on the importance of novae as producers of lithium.…”

“…This assumption of a metallicity dependent occurrence probability for this kind of systems is supported observationally by the studies of Gao et al (2014Gao et al ( , 2017 and Yuan et al (2015), and it can be crucial to explain the decrease of lithium at high metallicities. Other alternative explanations that have been proposed in the literature to explain this feature by means of chemical evolution models are: i) lower yields of Li from stars at high metallicities, even if no physical reasons for this fact can be found (Prantzos et al 2017); and ii) stellar migration of stars coming from the inner regions of the Milky Way disc (Guiglion et al 2019).…”

“…A better understanding of the formation and evolution of the nova systems is needed before we can work out a more refined model. Other possible explanations that have been proposed for the decrease at high metallicities are: i) lower yields of Li from single stars at high metallicity (Prantzos et al 2017), even if no physical justification for this fact can be found, and ii) the effect of radial migration of stars reflecting different evolutionary paths from the inner thin disc regions (Guiglion et al 2019). Some uncertainties might be introduced by the Li depletion in the super-solar metallicity stars.…”