关键词: 外星行星, 类地行星, 宜居带, 凌星, 天体测量卫星

Abstract: Some of scientists in our country have suggested to launch a dedicated satellite of astrometry in a few years, using astrometry technology with 0.5 micro-arcsecond precision, to search terrestrial planets surrounding about 200 sun-like stars within a distance of about 64 light-years, and to obtain a complete sample of possible habitable planets within the distance. Then, the stars of this sample would be followed up with high precision photometry on large ground-based telescopes or other suitable space-based telescopes to detect the candidates with the transits on host stars, and with high-resolution spectroscopy for these transits to determine whether atmospheres exists on the transit planets and the chemical composition of the atmospheres, especially whether the features
of biosignature gases are emerged, and ultimately it be determined whether life is really on the planets or not. If we would be able to finally find such a planet, it will undoubtedly be a great achievement in the sciences.

Key words: exoplanet, terrestrial planet, habitable zone, transit, satellite of astrometry