搜寻第二个地球——系外地球(ET)巡天计划OA北大核心CSTPCD

The Earth 2.0(ET)mission will pioneer the international breakthrough in the frontier sci-entific issue of the existence and evolution of Earth 2.0s(or exo-Earths)in the origin of life by adopting the key technology of ultra-high precision photometry with a large field of view in space.The ET mis-sion will deploy a space observatory consisting of six wide-field transit telescopes and one micro-lensing telescope in a halo orbit at the Sun-Earth Lagrange L2 point.Combining transit and micro-lensing meth-ods,utilizing the ultra-large field of view and ultra-high precision optical photometry observations in space,the ET mission will for the first time discover historically significant Earth 2.0s and determine their occurrence rate.It will conduct the first large-scale survey of terrestrial-like and free-floating plan-ets,discover free-floating Earth-mass planets and measure their occurrence rates,reveal the origins of Earth-like and free-floating planets,and provide candidates and new directions for the search for ex-traterrestrial life.The observational results,statistical studies,and theoretical tests of the ET mission will answer pressing frontier scientific questions such as"How common are Earth-like planets in the uni-verse","How do Earth-like planets form and evolve"and"How do free-floating planets originate".Fol-low-up observations of the Earth 2.0 samples discovered by the ET mission will precisely measure their mass,density,and atmospheric composition,contributing to an in-depth study of their habitability char-acteristics.Moreover,the study of the large number of various exoplanet samples newly discovered by ET,as well as tests of theories,will promote a deeper understanding of the formation and evolution of these types of planets.ET's abundant high-precision,high-cadence,and long-baseline photometric data will advance research in fields such as asteroseismology,Galactic archaeology,time-domain astronomy,binary stars,and binary black holes.