Radial Velocity Survey for Planets around Young stars (RVSPY) A transiting warm super-Jovian planet around HD 114082, a young star with a debris disk

Abstract

Aiming to detect planetary companions to young stars with debris disks via the radial velocity method, we observed HD114082 during April 2018 - August 2022 as one of the targets of our RVSPY program (Radial Velocity Survey for Planets around Young stars). We used the FEROS spectrograph, mounted to the MPG/ESO 2.2 m telescope in Chile, to obtain high signal-to-noise spectra and time series of precise radial velocities (RVs). Additionally, we analyzed archival HARPS spectra and TESS photometric data. We used the CERES, CERES++ and SERVAL pipelines to derive RVs and activity indicators and ExoStriker for the independent and combined analysis of the RVs and TESS photometry. We report the discovery of a warm super-Jovian companion around HD114082 based on a 109.8$\pm$0.4 day signal in the combined RV data from FEROS and HARPS, and on one transit event in the TESS photometry. The best-fit model indicates a 8.0$\pm$1.0 Mjup companion with a radius of 1.00$\pm$0.03 Rjup in an orbit with a semi-major axis of 0.51$\pm$0.01 au and an eccentricity of 0.4$\pm$0.04. The companions orbit is in agreement with the known near edge-on debris disk located at about 28 au. HD114082b is possibly the youngest (15$\pm$6 Myr), and one of only three younger than 100 Myr giant planetary companions for which both their mass and radius have been determined observationally. It is probably the first properly model-constraining giant planet that allows distinguishing between hot and cold-start models. It is significantly more compatible with the cold-start model.