FLORES TRIVIGNO Matias Gaston
High-precision analysis of binary stars with planets. Searching for condensation temperature trends in the HD 106515 system
CARLOS SAFFE; JOFRÉ, E.; PAULA MIQUELARENA; MARCELO JAQUE ARANCIBIA; FLORES, M.; LÓPEZ FERNANDO MARCELO; COLLADO, ANA
ASTRONOMY AND ASTROPHYSICS
EDP SCIENCES S A
Lugar: Paris; Año: 2019 vol. 625
Aims. We explore for the first time the probable chemical signature of planet formation in the remarkable binary system HD 106515. The star A hosts a massive long-period planet with ∼9 MJup detected by radial velocity, while there is no planet detected in the B star. We also refine stellar and planetary parameters by using non-solar-scaled opacities when modeling the stars.Methods. We carried out a simultaneous determination of stellar parameters and abundances, by applying for the first time non-solar-scaled opacities in this binary system, in order to reach the highest possible precision. We used a line-by-line strictly differentialapproach, using the Sun and then the A star as reference. Stellar parameters were determined by imposing ionization and excitationbalance of Fe lines, with an updated version of the FUNDPAR program, ATLAS12 model atmospheres and the MOOG code. Opacitiesfor an arbitrary composition were calculated through the opacity sampling method. The chemical patterns were compared with solar-twins condensation temperature T c trends from literature and also mutually between both stars. We take the opportunity to compareand discuss the results of the classical solar-scaled method and the high-precision procedure applied here.Results. The stars A and B in the binary system HD 106515 do not seem to be depleted in refractory elements, which is different when comparing the Sun with solar-twins. Then, the terrestrial planet formation would have been less efficient in the stars of this binary system. Together with HD 80606/7, this is the second binary system which does not seem to present a (terrestrial) signature of planet formation, and hosting both systems an eccentric giant planet. This is in agreement with numerical simulations, where the early dynamical evolution of eccentric giant planets clear out most of the possible terrestrial planets in the inner zone. We refined the stellar mass, radius and age for both stars and found a notable difference of ∼78 % in R⋆ compared to previous works. We also refined the planet mass to mp sin i = 9.08 ± 0.20 MJup , which differs by ∼6 % compared with literature. In addition, we showed that the non-solar-scaled solution is not compatible with the classical solar-scaled method, and some abundance differences are comparable to NLTE or GCE effects specially when using the Sun as reference. Then, we encourage the use of non-solar-scaled opacities in high-precision studies such as the detection of Tc trends.