Insights into the Atmosphere of HD 202772 A b: New Findings from Spitzer Observations
Recent research has focused on the inflated hot Jupiter, HD 202772 A b, which orbits an early-type primary star in the evolved binary system HD 202772. This study, titled "Modeling Spitzer 3.6 and 4.5 μm Eclipse Depths for the Inflated Hot Jupiter in the Evolved Binary System HD 202772," presents a detailed analysis of eclipse light curve observations obtained using the Spitzer Space Telescope.
The researchers report eclipse depths of 680 ± 68 ppm and 1081+54-53 ppm for the 3.6 μm and 4.5 μm channels, respectively. These measurements correspond to day-side effective temperatures of 2130+102-91 K and 2611+46-49 K. The findings indicate that the Bond albedos are consistent with the distribution observed for hot Jupiters using both Spitzer and TESS.
Furthermore, the study highlights heat redistribution efficiencies that align with the Bond albedo range predicted by one-dimensional atmospheric models in radiative-convective equilibrium. The efficiencies are reported as 0.71 ± 0.10 and 0.03+0.03-0.02, suggesting a weak day-night temperature contrast for the former and a strong contrast for the latter.
The authors recommend follow-up observations with the James Webb Space Telescope (JWST) to further investigate the atmospheric composition and structure of HD 202772 A b, as well as its host stellar environment. This research aims to enhance understanding of how the atmospheres of close-in giant planets evolve in binary star systems beyond the main sequence.
For more details, the full paper can be accessed here.