Following the TraCS of exoplanets with Pan-Planets: Wendelstein-1b and Wendelstein-2b

Hot Jupiters seem to get rarer with decreasing stellar mass. The goal of the Pan-Planets transit survey was the detection of such planets and a statistical characterization of their frequency. Here, we announce the discovery and validation of two planets found in that survey, Wendelstein-1b and Wendelstein-2b, which are two short-period hot Jupiters that orbit late K host stars. We validated them both by the traditional method of radial velocity measurements with the HIgh Resolution Echelle Spectrometer and the Habitable-zone Planet Finder instruments and then by their Transit Color Signature (TraCS). We observed the targets in the wavelength range of 4000−24 000 Å and performed a simultaneous multiband transit fit and additionally determined their thermal emission via secondary eclipse observations. Wendelstein-1b is a hot Jupiter with a radius of 1.0314_(−0.0061)^(+0.0061) R_J and mass of 0.592_(−0.129)^(+0.0165) M_J, orbiting a K7V dwarf star at a period of 2.66 d, and has an estimated surface temperature of about 1727₋₉₀⁺⁷⁸ K. Wendelstein-2b is a hot Jupiter with a radius of 1.1592_(−0.0210)^(+0.0204) R_J and a mass of 0.731_(−0.311)^(+0.0541) M_J, orbiting a K6V dwarf star at a period of 1.75 d, and has an estimated surface temperature of about 1852₋₁₄₀⁺¹²⁰ K. With this, we demonstrate that multiband photometry is an effective way of validating transiting exoplanets, in particular for fainter targets since radial velocity follow-up becomes more and more costly for those targets.