Chemical signatures of planetary systems in their host stars. Near-infrared spectroscopy of four planet-hosting wide binaries

An important open question in exoplanet studies is whether planets can leave detectable chemical fingerprints on their host stars. While several studies have suggested possible planetary chemical signatures in planet-hosting stars, including the Sun, their true origin remains debated because of stellar birth conditions and evolutionary effects. Wide binaries, whose components share a common formation environment and have evolved without significant mutual interactions, provide an ideal testbed for identifying planetary chemical signatures. Such signatures are often characterized by differential abundance trends with condensation temperature (T_ cond), which traces the partitioning between gaseous and rocky planetary material. We aim to investigate whether these trends are associated with the known planetary architectures of planet-hosting wide binaries. We obtained high-resolution near-infrared spectra of four planet-hosting wide binaries with IGRINS at Gemini-South. We measured chemical abundances for both components and analyzed differential abundances in each system. We also compiled literature measurements for planet-hosting and non-planet-hosting wide binaries and compared their T_ cond trends. Two systems (WASP-160 A/B and WASP-127/TYC 4916-897-1) exhibit statistically significant abundance trends with T_ cond, while HD 20782/HD 20781 shows a weaker correlation, and K2-54/K2-54 B is consistent with a flat relation. The observed trends display diverse behaviors, including both volatile- and refractory-enhanced patterns in planet-hosting stars. Literature comparisons indicate that extreme T_ cond slopes may occur more frequently among planet-hosting wide binaries, particularly at large binary separations, although the broader statistical picture remains limited by sample size and sample definition. Our results indicate that chemical signatures in planet-hosting wide binaries are not universal but vary across systems. While planetary architectures may be associated with some of the observed host-star abundance patterns, multiple competing processes are likely to contribute to the observed trends. Larger samples of both planet-hosting and non-planet-hosting wide binaries, including those observed with near-infrared spectroscopy, will be essential to more robustly disentangle planetary signatures from stellar and binary effects.