Investigation of Transit Timing and an Optical Transmission Spectrum of the Hot Jupiter WASP-11 b

WASP-11 b/HAT-P-10 b is an inflated hot Jupiter, which has a low density that makes it a good target for atmospheric studies using the transmission spectroscopy technique. In this work, we present 31 new transit light curves of WASP-11 b/HAT-P-10 b, obtained through the Spectroscopy and Photometry of Exoplanet Atmospheres Research Network. These data were analyzed along with previously published ground-based observations and space-based data from TESS. We refine the planetary parameters of WASP-11 b/HAT-P-10 b and perform a transit timing analysis using data spanning 16 yr. The updated (O − C) diagram shows no significant evidence of orbital decay. Transit-timing variation analysis reveals no significant signals indicative of additional planets. Atmospheric analysis using multiband optical observations indicates a strong Rayleigh scattering slope in the transmission spectra, which may originate from the planetary atmosphere itself or be influenced by contamination such as stellar activity or light from the companion star.