The bimodal A(Li) distribution of Milky Way's thin disk stars and the Galactic scale events

ROCA-FÀBREGA, S.; LLORENTE DE ANDRÉS, F.; CIFUENTES, C; CHAVERO, C.; DE LA REZA, R.

Madrid-online

Congreso; XIV Scientific Meeting of the Spanish Astronomical Society; 2020

Sociedad Española de Astronomia

It is well known that the lithium abundance in stellar atmospheres, A(Li), suffers from several enhancement and depletion processes during the lifetime of the star. Although several studies demonstrated that these processes are mostly related with the physics of star formation, of protostellar/protoplanetary disks, and of stellar internal dynamics, galactic scale events may also play an important role. The initial [Fe/H] and A(Li) of the star forming gas clouds sets the main properties of protostellar/protoplanetary disks, and thus, how the A(Li) evolves in the star?s pre-main sequence and further on. In this paper we study how changes in the [Fe/H]induced by Galactic scale events, have an impact on the A(Li) evolution. We also investigate how the observed bimodal A(Li) distribution is generated and we confirm that the A(Li)-poor and A(Li)-rich components are connected by a region with low number of stars that we refer as an ?isthmus? throughout this work. We demonstrate that the bimodal A(Li) distribution is in fact a direct consequence of a particular Milky Way star formation history profile combined with the stellar evolution?s 7Li depletion mechanisms. We show that A(Li) evolution can be used as a proxy for the Star Formation History of our Galaxy.