Analysis Of Errors In STEP Astrometry

Since the first extrasolar planetary system has been discovered,for more than 20 years,the search for exoplanets has developed a series of detection methods and made great progress.The space telescope Search for Terrestrial Exo-Planets(STEP)em-ployed a method of sub-pixel technology which ensures that the astrometric accuracy of telescope on the focal plane is at the order of 1?as.Compared to other methods,STEP is currently the only space intermediation program that can detect to terrestrial exoplanets.The first chapter of the paper briefly introduces the relevant background knowl-edge,including five detection methods of exoplanets,and three exoplanets or extrasolar planetary systems t hat attract great attention and have great research value.In the sec-ond chapter,we introduce the characteristics and advantages of the planetary system outside the STEP observation system,and further select the observation goal of STEP and the differential observation method.In the third and fourth chapters,we analyze the influence of some key factors,including errors in the stellar proper motions,parallax,the optical center of the system,and the velocities and positions of the satellite,on the detection of exoplanets.In the fifth chapter,by simulating the five-year observation data of the stars of the exoplanets in three cases,the least squares method is used to fit the parameters of the planetary system,and it is concluded that STEP can observe the planetary system.In the last chapter,we summarize and discuss the results of this paper,and give some follow-up research direction.