Detailed spectroscopic and photometric analysis of the remarkable planet-hosting wide binary system HD 202772A/B

ABSTRACT We conducted a detailed spectroscopic and photometric characterization of the planet-hosting wide binary HD 202772A/B. No planet has been detected around HD 202772B, whereas HD 202772A, more evolved than its companion and near the end of its main-sequence (MS) phase, hosts a transiting hot Jupiter. The system has one of the hottest components ($T_{\mathrm{eff}; A} \sim 6440$ K) and one of the largest surface gravity differences between components ($\Delta \log g_{A-B} \sim 0.4$ dex) among MS planet-hosting wide binaries. Using a global fit including our stellar parameters, radial velocities, and new data from the Transiting Exoplanet Survey Satellite (TESS), we derive refined properties of the planet orbiting HD 202772A, finding it to be the most irradiated hot Jupiter known in a wide binary. We also constrain the presence of additional transiting planets around HD 202772A and new transiting planets around HD 202772B using TESS photometry. We derive high-precision, strictly differential abundances for 27 species based on Gemini-GRACES spectra. HD 202772A shows lower lithium abundance (by 0.45 dex) relative to B, consistent with their stellar parameter differences. We also detect a small but significant enhancement in refractory elements in HD 202772A, particularly those with condensation temperatures above 1400 K (+0.018 $\pm$ 0.004 dex). We explored several scenarios to explain the observed chemical anomalies. Our analysis suggests that rocky planet engulfment, primordial inhomogeneities, and $\delta$ Scuti-related effects are unlikely to fully account for the chemical pattern. Instead, the differences observed in certain refractory elements might support atomic diffusion as the most plausible explanation.

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Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-11-03
DOI
https://doi.org/10.1093/mnras/staf1906
Primary Topic
Stellar, planetary, and galactic studies
Type
article
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article

Detailed spectroscopic and photometric analysis of the remarkable planet-hosting wide binary system HD 202772A/B

C. Saffe, R. F. Díaz, M. Cerioni, L. García et al.
Monthly Notices of the Royal Astronomical Society
Stellar, planetary, and galactic studies
article

Detailed spectroscopic and photometric analysis of the remarkable planet-hosting wide binary system HD 202772A/B

C. Saffe, R. F. Díaz, M. Cerioni, L. García, Eder Martioli, J. Meléndez, María Paula Ronco, L. Saker, Matías Flores Trivigno, Leslie Hebb, E. Jofré, Jhon Yana Galarza, P. Miquelarena, F. Faedi, Cintia F. Martínez, R. Petrucci, Camila Zuloaga
article en

Abstract

ABSTRACT We conducted a detailed spectroscopic and photometric characterization of the planet-hosting wide binary HD 202772A/B. No planet has been detected around HD 202772B, whereas HD 202772A, more evolved than its companion and near the end of its main-sequence (MS) phase, hosts a transiting hot Jupiter. The system has one of the hottest components ($T_{\mathrm{eff}; A} \sim 6440$ K) and one of the largest surface gravity differences between components ($\Delta \log g_{A-B} \sim 0.4$ dex) among MS planet-hosting wide binaries. Using a global fit including our stellar parameters, radial velocities, and new data from the Transiting Exoplanet Survey Satellite (TESS), we derive refined properties of the planet orbiting HD 202772A, finding it to be the most irradiated hot Jupiter known in a wide binary. We also constrain the presence of additional transiting planets around HD 202772A and new transiting planets around HD 202772B using TESS photometry. We derive high-precision, strictly differential abundances for 27 species based on Gemini-GRACES spectra. HD 202772A shows lower lithium abundance (by 0.45 dex) relative to B, consistent with their stellar parameter differences. We also detect a small but significant enhancement in refractory elements in HD 202772A, particularly those with condensation temperatures above 1400 K (+0.018 $\pm$ 0.004 dex). We explored several scenarios to explain the observed chemical anomalies. Our analysis suggests that rocky planet engulfment, primordial inhomogeneities, and $\delta$ Scuti-related effects are unlikely to fully account for the chemical pattern. Instead, the differences observed in certain refractory elements might support atomic diffusion as the most plausible explanation.

Monthly Notices of the Royal Astronomical SocietyVol. 544(4)
Hobart and William Smith Colleges (US), Consejo Nacional de Investigaciones Científicas y Técnicas (AR), University of Leicester (GB), Universidad Autónoma de la Ciudad de México (MX), University of Concepción (CL), Universidade de São Paulo (BR), Carnegie Institution for Science (US), National University of San Juan (AR), Instituto de Astronomía Teórica y Experimental (AR), Argentine National Observatory (AR), Instituto de Ciencias Astronómicas, de la Tierra y del Espacio (AR), Instituto de Física La Plata (AR), Carnegie Observatories (US), Centro Científico Tecnológico - La Plata (AR), International Center for Advanced Studies (AR), Laboratório Nacional de Astrofísica (BR), Universidad Nacional de La Plata (AR), Universidad Nacional Autónoma de México (MX)
Openalex Percentile: Top 77%
Stellar, planetary, and galactic studies
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