A comprehensive homogeneous investigation of orbital ephemeris and transmission spectrum of WASP-19 b

Exoplanets with ultra-short periods (P < 1 day) might experience orbital decay due to the tidal dissipation effect with the host star. My current work allows verification of the orbital ephemeris of the WASP-19b with the availability of long-term high-precision photometric and spectroscopic data including 20 unpublished transits from the Danish telescope. This place limits on the modified tidal quality factor Q’* The same data allows for a detailed study of the atmospheric properties of WASP-19b, via transmission photometry and spectroscopy. WASP-19A is an active host star with its surface littered with starspots, which if not correctly modeled, systematics are introduced into the transit timing measurements and transit depth, which latter affects the exoplanetary transmission spectrum. Additionally the signal from stellar inhomogeneities can outweigh the signal from planetary spectral characteristics (Rackham, B., V., et al. 2022, arXiv, 220109905, submitted to RAS Techniques and Instruments as invited review.). Therefore, to perform a full and complete orbital ephemeris study of WASP-19b requires the modeling of detected starspots. Incidentally, failing to model both occulted and unocculted starspots can skew measurements in the planetary radius affecting the broadband transmission spectrum. Using the transit-starspot model, PRISM we perform the most complete, detailed, homogeneous analysis of all available data to estimate Q’* and study the atmospheric properties of WASP-19b with the help of ground- and space-based archival data