2019A&A...628A.126M

The binary system 16 Cygni is key in studies of the planet-star chemical composition connection, as only one of the stars is known to host a planet. This allows us to better assess the possible influence of planet interactions on the chemical composition of stars that are born from the same cloud and thus should have a similar abundance pattern. In our previous work, we found clear abundance differences for elements with Z≤30 between both components of this system and a trend of these abundances as a function of the condensation temperature (T_c), which suggests a spectral chemical signature related to planet formation. In this work we show that our previous findings are still consistent even if we include more species, such as the volatile N and neutron capture elements (Z>30). We report a slope with T_c of 1.56±0.24x10^–5dex/K, that is good agreement with our previous work. We also performed some tests using ARES and iSpec to measure automatically the equivalent width and found T_c slopes in reasonable agreement with our results as well. In addition, we determined abundances for Li and Be by spectral synthesis, finding that 16 Cyg A is richer not only in Li but also in Be, when compared to its companion. This may be evidence of planet engulfment, indicating that the T_c trend found in this binary system may be a chemical signature of planet accretion in the A component, rather than an imprint of the giant planet rocky core formation on 16 Cyg B.