Using non-solar-scaled opacities to derive stellar parameters. Toward high-precision parameters and abundances

CARLOS SAFFE; FLORES, M.; PAULA MIQUELARENA; LÓPEZ FERNANDO MARCELO; MARCELO JAQUE ARANCIBIA; COLLADO, ANA; JOFRÉ, E.; PETRUCCI, R

La Serena

Congreso; Second Binational Meeting AAA-SOCHIAS; 2018

Sociedad Chilena de Astronomía (SOCHIAS) y la Asociación Argentina de Astronomía (AAA)

We implemented non-solar-scaled opacities in a simultaneous derivation of fundamental parameters and chemical abundances, in order to compare the results with the classical solar-scaled approach. Our sample is composed of 20 stars (10 main-sequence and 10 evolved objects), with six stars belonging to binary systems. The stellar parameters were determined by imposing ionization and excitation equilibrium of Fe lines, with an updated version of the FUNDPAR program, together with plane-parallel ATLAS12 model atmospheres and the MOOG code. Opacities for an arbitrary composition and v micro were calculated through the OS (Opacity Sampling) method. Detailed abundances were derived using equivalent widths and spectral synthesis with the MOOG program. We applied the full line-by-line differential technique using the Sun as reference star, both in the derivation of stellar parameters and in the abundance determination. We start using solar-scaled models in a first step, and then continue the process but scaling to the abundance values found in the previous step (i.e. non-solar-scaled). The process finishes when the stellar parameters of one step are the same of the previous step, i.e. we use a doubly-iterated method.