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

Speaker: Prof. Jian Ge, University of Florida

Host: Taotao Fang

Time: 16:30-18:30, Thursday, Nov 7, 2019

Location: Physics Building 552

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?”.

About the speaker:

葛健教授现为佛罗里达大学天文学终身教授(2004-现在),曾为宾州州立大学助理教授(2000-2004)，利物浦国家实验室博士后(1998-2000)。于1989年获中国科大的理学学士, 1998年获亚利桑那大学天文学博士。葛健是达摩近邻宜居行星巡天的创始人和首席科学家,少年科学天才训练项目创始人，科幻片《星际迷航》中的瓦肯星的发现者，第一位找到地外行星的华裔科学家，国际斯隆数字巡天三期MARVELS多目标地外行星巡天创始人和首席科学家以及斯隆数字巡天三期管理委员会成员,美国航空航天局(NASA)TESS空间探索项目合作伙伴。2018年曾入选《中国留学生的四十年》的四十位杰出留学生，现兼任中国科学院海外评审专家、中国极地科学杂志国际编委成员、中国科学，副主编、中国国际30米望远镜科学咨询委员会成员、上海天文台顾问、中国科技大学客座教授等。

他长期从事实测天文，天文技术和仪器研究。研究领域包括系外行星，褐矮星和双星巡天,系外行星探测技术和仪器,红外高色散光谱仪技术和仪器,及新一代高清晰度成象技术,类星体吸收线和河外星系际界质和深度学习在天文大数据应用。他在国际顶级期刊和技术会议文集上发表科学技术论文共300多篇，并拥有三个美国国家专利。