The peculiar chemical pattern of the WASP-160 binary system: signatures of planetary formation and evolution?

TL;DR

This study investigates the chemical composition of the binary star system WASP-160, revealing peculiar abundance patterns potentially linked to planetary formation processes, and highlights the need for further observations to understand these signatures.

Contribution

First detailed differential chemical abundance analysis of the WASP-160 binary system, revealing signatures possibly related to planet formation and evolution.

Findings

Detected a correlation between elemental abundances and condensation temperatures.

Found a deficit of volatiles and an enhancement of refractories in WASP-160B relative to WASP-160A.

Identified chemical patterns similar to other planet-hosting binaries, suggesting planet formation influence.

Abstract

Wide binary stars with similar components hosting planets provide a favorable opportunity for exploring the star-planet chemical connection. We perform a detailed characterization of the solar-type stars in the WASP-160 binary system. No planet has been reported yet around WASP-160A while WASP-160B is known to host a transiting Saturn-mass planet, WASP-160B b. For this planet, we also derive updated properties from both literature and new observations. Furthermore, using TESS photometry, we constrain the presence of transiting planets around WASP-160A and additional ones around WASP-160B. The stellar characterization includes, for the first time, the computation of high-precision differential atmospheric and chemical abundances of 25 elements based on high-quality Gemini-GRACES spectra. Our analysis reveals evidence of a correlation between the differential abundances and the condensation temperatures of the elements. In particular, we find both a small but significant deficit of volatiles and an enhancement of refractory elements in WASP-160B relative to WASP-160A. After WASP-94, this is the second stellar pair among the shortlist of planet-hosting binaries showing this kind of peculiar chemical pattern. Although we discuss several plausible planet formation and evolution scenarios for WASP-160A and B that could explain the observed chemical pattern, none of them can be conclusively accepted or rejected. Future high-precision photometric and spectroscopic follow-up, as well as high-contrast imaging observations, of WASP-160A and B, might provide further constraints on the real origin of the detected chemical differences.