Observation Simulation and Orbital Retrieval of the CHES Satellite

Abstract

So far, most of the exoplanets have been discovered with the radial velocity and transient methods. In comparison with these detection techniques, the astrometric method has unique advantages in the determination of planetary orbital parameters and masses. Closeby Habitable Exoplanet Survey (CHES) will search for terrestrial planets in the habitable zone around 100 sun-like stars in the solar system's neighbors (about 10 pc from the sun) using the micro-arcsecond space astrometry method, and further carry out a comprehensive census of nearby planetary systems to obtain the true mass of planets and three-dimensional orbital parameters to establish a complete database of the nearby planetary systems. Based on the observation mode and scientific objectives of the CHES satellite, this work conducted the simulated observations on Alpha Centauri A, a simulated solar system, 51 Peg, and the black hole Cyg X-1, and generated astrometric simulation data. Using two periodic spectra of Lomb-Scargle and BIC (Bayesian information criteria), the signal of the planetary orbit period is analyzed, and the orbit inversion of the planetary system is carried out with the Markov Chain Monte Carlo (MCMC) algorithm. In addition, this work further discusses the influence of the planets around the reference stars on the detection of habitable planets, and the BIC periodic spectrum can be used to identify the reference stars that may have planets around them.