The resonant structure of the TRAPPIST-1 system revealed by an accurate solution of the inverse problem of the TTV time-series obtained with a genetic algorithm

D. D. CARPINTERO; M. D. MELITA

Antofagasta

Congreso; XVI Latin American Regional IAU Meeting; 2019

Sociedad Chilena de Astronomía y Unión Astronómica Internacional

The TRAPPIST-1 planetary system is composed of 7 transiting planets which are known to be in a resonant remarkable state. It must be noted that the elements provided by other authors produce an apparent linear drift, which is indicative that the orbital elements, particularly the semimajor axes, are not accurately determined. We have searched for a solution for the inverse problem of the transits times-series of the 7 planets that fit the observed transit times almost within the error bars of the observtions. We have estimated the uncertainty of the obtained solution using a MCMC with relative deviations of only 1/106 which produced solutions such that 95% of them were within a mean time difference with respect the observations of about 2.5 min. The mean difference between computed (C) and observed (O) times is 2 minutes, which corresponds to an approximate difference between the C and O planetary angles of only 2.5?. Therefore this solution enabled us to explore more accurately the resonant state of the system by studying the evolution of the critical angles in order to determine if they are rotating or librating. We have determined that there are no 2-body librating resonances. Moreover, not all 3-body resonances between adjacent bodies are librating and, more noticealy, a 3-body resonace between non-contiguous planes was found.