TOI-1861 b: Confirmation of a Warm Jupiter through Joint Transit and RV Modeling

Abstract

As of today, thousands of exoplanet candidates are waiting to be either confirmed as planets, or rejected. In this work, one of these candidates’ planetary nature was confirmed through modeling both transit- and radial velocity (RV) data with the software pyaneti. The confirmed planet, TOI-1861 b, is a warm Jupiter with a mass of 1.0 ˘ 0.1MJ, a radius of 1.00 ˘ 0.05RJ, an eccentricity of 0.10 ˘ 0.02, and an orbital period of 185.6281 ˘ 0.0001 days. Light curves from the Transiting Exoplanet Survey Satellite (TESS) were used, in combination with RV data, created from spectra collected with the High Accuracy Radial Velocity Planet Searcher (HARPS). The model was constructed using the software pyaneti, which applies Bayesian statistics and Markov Chain Monte Carlo (MCMC) sampling to determine the planetary parameters that best reproduce the observations. In addition to confirming the planet, the fitted orbital period rules out the previously proposed orbital period of 742 days, which was based solely on transits detected in the TESS light curves. The analysis therefore demonstrates the importance of joint transit and RV modeling for resolving ambiguities caused by periodic signal aliasing.