Analogue Simulation and Orbit Solution Algorithm of Astrometric Exoplanet Detection

Astrometry is an effective measure to detect exoplanets. It has many advantages that other detection methods do not bear, such as providing three dimensional planetary orbit, and determining planetary mass, etc. Astrometry will enrich the sample of exoplanets. As the high-precision astrometric satellite Gaia (Global Astrometry Interferometer for Astrophysics) was launched in 2013, it is predictable that there will be abundant long-period Jupiter-size planets to be discovered by Gaia. In this paper, we specify the α Centauri A, HD 62509, and GJ 876 systems, and generate the synthetic astrometric data with the single-time astrometric precision of Gaia. Then we use the Lomb-Scargle periodogram to analyze the periodical signal of planetary orbit, and use the Markov Chain Monte Carlo (MCMC) algorithm to make the orbit inversion of the planetary system, the obtained result is well coincident with the initial parameters of the planet.