The bi-modal $^7$Li distribution of the Milky Way's thin-disk dwarf stars: The role of Galactic-scale events and stellar evolution

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

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2021 vol. 656

0004-6361

The lithium abundance, A(Li), in stellar atmospheres suffers from various enhancement and depletion processes during the star´s lifetime. While several studies have demonstrated that these processes are linked to the physics of stellar formation and evolution, the role that Galactic-scale events play in the galactic A(Li) evolution is not yet well understood. We aim to demonstrate that the observed A(Li) bi-modal distribution, in particular in the FGK-dwarf population, is not a statistical artefact and that the two populations connect through a region with a low number of stars. We also want to investigate the role that Galactic-scale events play in shaping the A(Li) distribution of stars in the thin disk. We use statistical techniques along with a Galactic chemical evolution model for A(Li) that includes most of the well-known 7 Li production and depletion channels. We confirm that the FGK main-sequence stars belonging to the Milky Way´s thin disk present a bi-modal A(Li) distribution. We demonstrate that this bi-modality can be generated by a particular Milky Way star formation history profile combined with the stellar evolution´s 7 Li depletion mechanisms. We show that A(Li) evolution can be used as an additional proxy for the star formation history of our Galaxy.