Testing lambda Bootis formation scenarios

ALACORIA, JOSÉ; MIQUELARENA, PAULA; CALVO, DANIELA; MARTIN GIRARDI, GIMENA; SAFFE, CARLOS

Córdoba

Congreso; 63 Reunión de la Asociación Argentina de Astronomía; 2021

OAC

The λ Bootis stars are chemically peculiar objects that show solar abundances of C, N, O and S, together with subsolar values of other metals. A number of possible scenarios were proposed to explain this chemical pattern although without conclusive results. In particular, the accretion scenario propose that the peculiarity is due to the interaction of an early-type star with a diffuse cloud. This could be tested by observing a binary (or multiple) system, where both early-type components should display, in principle, the same peculiarity. However, this test was performed very few times, showing a clear need of additional studies. In this work we propose to analyze the remarkable triple system HD 15165, composed by two early-type stars (with a λ Bootis candidate) and a late-type companion. This system provides a unique opportunity to test the accretion scenario of λ Bo¨otis stars, with important consequences depending on the resulting abundances. In addition, the 3rd star of the system would be indicative of the primordial composition, being then an ideal system to study through Gemini+GRACES spectra.