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

¹ Max-Planck-Institute for Extraterrestrial Physics, Garching, Gießenbachstraße, 85741 Garching, Germany
² University Observatory Munich (USM), Scheinerstraße 1, 81679 Munich, Germany
e-mail: jsteuer@usm.lmu.de
³ Max-Planck-Institute for Astronomy, Heidelberg, Königstuhl 17, 69117 Heidelberg, Germany
⁴ Department of Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802, USA
⁵ Center for Exoplanets & Habitable Worlds, University Park, PA 16802, USA
⁶ Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08540, USA
⁷ Penn State Astrobiology Research Center, University Park, PA 16802, USA
⁸ Department of Astronomy, University of California, Berkeley CA 94720, USA
⁹ California Institute of Technology, Pasadena, CA 91125, USA
¹⁰ Department of Astronomy, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan

Received: 12 February 2020
Accepted: 25 May 2020

Abstract

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.