Space and Ground-based Searching for Earth 2.0s----中国科学院紫金山天文台

Seminar Title	Space and Ground-based Searching for Earth 2.0s

Speaker:	Prof. GE Jian

Affiliation:	(Department of astronomy, university of Florida)

When	Tuesday afternoon, Oct. 29, 14:00p.m.

Where:	Room 302 No.3 building , Xianlin campus (PMO, CAS)
	Welcome to Attend

	( PMO Academic Committee & Academic Circulating committee)

Abstract: The 2019 Nobel prize in Physics was awarded to Drs. Mayor and Queloz for detection of the first giant planet orbiting a sun-like star, 51 Peg. This has concluded the first phase of mankind’s search for extrasolar worlds. We can now answer that we are NOT the only planet in the universe. There are thousands of known extrasolar worlds out there. All of them show very different characteristics from our own system. The next natural phase of mankind’s search for extrasolar worlds is to look for Earth-like habitable worlds orbiting sun-like stars, called Earth 2.0s, and possible life signatures on them. I will first summarize the current status, including work carried out by my group, in this search, then present a four-year space mission concept, called Super Kepler, to monitor over 200,000 sun-like stars in the original Kepler and its surrounding 1800 square-degree field (17 times the Kepler field) with a seven 30cm telescope array from year 2025 to 2029. The goals are to detect over 10 Earth 2.0s and determine the occurrence rate of Earth 2.0s for the first time. The extremely weak signals produced by these Earth 2.0s creates major challenges not only in detecting them with space high precision photometry missions, but also in characterizing them with ground-based spectroscopy facilities. Our study shows that only future 30-meter class telescopes equipped with a high stable, high precision, and high-resolution optical spectrograph can effectively characterize these elusive planet signals to measure their masses and densities, which can eventually determine their habitability. Specifically, the combination of the Super Kepler space mission with the TMT High Resolution Optical Spectrograph led by China’s team will provide the unique and most powerful next generation facilities to detect Earth 2.0s and help address mankind’s fundamental questions: “Are we alone in the universe?” and “Where did we come from?”.