HD 80606: searching for the chemical signature of planet formation

Abstract

Context. Binary systems with similar components are ideal laboratories that allow several physical processes to be tested, such as the possible chemical pattern imprinted by the planet formation process. Aims. We explore the probable chemical signature of planet formation in the remarkable binary system HD 80606−HD 80607. The star HD 80606 hosts a giant planet with ∼4 M Jup detected by both transit and radial velocity techniques, which is one of the most eccentric planets detected to date. We study condensation temperature T c trends of volatile and refractory element abundances to determine whether there is a depletion of refractories, which could be related to the terrestrial planet formation. Methods. We carried out a high-precision abundance determination in both components of the binary system via a line-by-line, strictly differential approach. First, we used the Sun as a reference and then we used HD 80606. The stellar parameters T eff , log g, (2009, A&A, 497, 563). The T c trends were also compared mutually between both stars of the binary system. Results. From the study of T c trends, we concluded that the stars HD 80606 and HD 80607 do not seem to be depleted in refractory elements, which is different for the case of the Sun. Then, following the interpretation of Meléndez et al. (2009), the terrestrial planet formation would have been less efficient in the components of this binary system than in the Sun. The lack of a trend in refractory elements with T c between both stars implies that the presence of a giant planet do not neccesarily imprint a chemical signature in their host stars, similar to the recent result of Liu et al. (2014, MNRAS, 442, L51). This is also in agreement with Meléndez et al. (2009), who suggest that the presence of close-in giant planets might prevent the formation of terrestrial planets. Finally, we speculate about a possible, ejected or non-detected, planet around the star HD 80607.

Abundance trend with condensation temperature for stars with different Galactic birth places

“…This very exciting and important (possible) connection between chemical peculiarities and formation of planets has also been examined in other works (e.g. Takeda et al 2001;Ecuvillon et al 2006;Sozzetti et al 2006;Schuler et al 2011b;González Hernández et al 2013;Maldonado et al 2015;Nissen 2015;Biazzo et al 2015;Saffe et al 2015Saffe et al , 2016, but contradictory conclusions were reached.…”

“…Several authors studied the T c trend in binary stars with and without planetary companions (e.g. Liu et al 2014;Saffe et al 2015;Mack et al 2016) or in binary stars where both components host planets (e.g. Biazzo et al 2015;Teske et al 2015Teske et al , 2016Ramírez et al 2015).…”

High-precision analysis of the solar twin HIP 100963

“…The analysis is based on the line-by-line differential method (e.g., Meléndez et al 2012Meléndez et al , 2014aMonroe et al 2013;Liu et al 2014;Ramírez et al 2014;Biazzo et al 2015;Nissen 2015;Spina et al 2016;Saffe et al 2015). We measured the EWs using the splot task in IRAF, fitting the line profiles using Gaussians.…”

ζ2Reticuli, its debris disk, and its lonely stellar companionζ1Ret

“…Several authors studied the T c trend in binary stars with and without planetary companions (e.g., Liu et al 2014;Saffe et al 2015;Mack et al 2016) or binary stars where both components host planets (e.g., Biazzo et al 2015;Teske et al 2015Teske et al , 2016Ramírez et al 2015). The results and conclusions of these studies show that there are no systematic differences in the chemical abundances of stars with and without planets in binary systems.…”