[PAE20-P04] Multi-band Simultaneous Transit Observations of Low Density Hot Jupiters
Keywords:exoplanet, atmosphere, transit observation
The derived transit parameters are in good agreement with previous results. Careful analysis of transit depth variation in each band shows a marginal increase in the planetary radius from the red toward the blue ends of the visible wavelength range. In addition, to compare the observed data with a theoretical atmospheric model, we calculate a model spectrum for each planet considering two cases: (case 1) 1x Solar and (case 2) 100x Solar metallicity clear atmospheres, assuming thermochemical equilibrium compositions and isothermal structures. Comparing the measured transit depths with the spectrum model for each planet, we found that our achieved photometric precision is not enough to robustly distinguish between the two atmospheric models. To test the significance of (non-)detection of Rayleigh scattering, a Monte Carlo fitting routine was performed using the posterior samples from MCMC of transit depth for each band. We find a marginal Rayleigh slope for HAT-P-12b at 1.0$\sigma$ and HAT-P-44b at 1.2$\sigma$. On the other hand, we find a positive slope for WASP-21b within 2.8$\sigma$ which cannot be explained by either atmospheric models. Instead, such trend can be explained by unocculted spots on the surface of WASP-21. Motivated by our results, we consider future multi-epoch observations of these systems as well as search for new targets feasible for detecting broad atmospheric features using MuSCAT and MuSCAT2.