The exceptional planetary system orbiting TOI-201: An eccentric brown dwarf in a 8-yr orbit coplanar to a warm Jupiter

Speaker: Dr. Matias Jones
Affiliation: ESO
Title: "The exceptional planetary system orbiting TOI-201: An eccentric brown dwarf in a 8-yr orbit coplanar to a warm Jupiter"

Abstract: In transiting planetary systems, where planetary sizes are accurately determined from transit observations, the presence of transit timing variations (TTVs), especially when combined with radial velocity (RV) data, provides powerful constraints on masses and orbital eccentricities. Together, these measurements offer crucial insights into system architecture, formation mechanisms, and dynamical evolution.  In this talk I will present a long-term RV and transit/TTV monitoring of the relatively young star TOI-201, which hosts an exceptional multi-planet system composed of a hot super-Earth size planet transiting every 5.8 days, a warm Jupiter on a 53-day orbit, and an eccentric low-mass brown dwarf on an approximately 8-year orbit.  The BD is the longest-period transiting substellar object ever characterized via RVs, and the only one known to be coplanar with inner planets. This system represents a unique multi-planet system, offering a rare window into the processes of planet formation and dynamical evolution. Its rare configuration provides invaluable insights into the formation and evolution pathways, suggesting a dynamically mild, coplanar and almost in-situ formation of a WJ, a highly eccentric BD, and a lone inner SE, within a common protoplanetary disk.