报告题目：Space and Ground-based Searching for Earth 2.0s（未来空间和地面搜寻地球2.0） 

　　报告人：葛健教授，佛罗里达大学天文系  

　　报告人简介：Dr. Jian Ge is a professor of astronomy at University of Florida. He was an assistant professor at Pennsylvania State University in 2000-2004, and a postdoc research fellow at Lawrence Livermore National Lab in 1998-2000. He received his Ph.D in Astronomy at the University of Arizona in 1998 and his BSc at University of Science and Technology of China in 1989.  

　　Dr. Ge is the Principal Investigator of the Dharma Planet Survey and a collaborator of the NASA TESS mission. He was PI for the MARVELS survey of the SDSS-III program in 2008-2014, PI for the TOU, EXPERT, LiJET, and W.M. Keck Exoplanet Tracker optical Doppler instruments and also FIRST near IR Doppler instrument. He led the development of dispersed fixed-delay interferometry for both single and multiple object Doppler spectroscopy and the first silicon grism and large format silicon immersion grating. He also led the development of advanced image slicer integral field optics, and new generation coronagraphic image and pupil masks for NASA Terrestrial Planet Finder (TPF). His team discovered five new planets (including planet Vulcan orbiting 40 Eridani), confirmed three transiting planets, 24 brown dwarfs, over 400 new binaries and over 10 low-mass planet candidates. Dr. Ge and his team also discovered about 700 high redshift quasar 2175 ？ dust absorbers and molecular hydrogen in four high-redshift damped Lyman alpha quasar absorbers, and measured high redshift Cosmic Microwave Background Radiation temperatures. He has published over 300 refereed journal and technical papers and abstracts, and was awarded with three US patents.   

　　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。 

　　报告摘要：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?”.   

　　2019年的诺贝尔物理奖授予了第一次在类太阳恒星附近发现巨行星的科学团队,这也宣布了人类在搜寻系外行星系统的第一阶段的正式结束。我们现在已非常确定太阳系不是宇宙中的唯一行星系统。事实上，我们已经知道在太阳系外有几千个行星系统。然而这些系统特质各异，和我们的太阳系很不相同。因此，人类在搜寻系外行星世界的第二阶段自然是去锁定在我们附近的类太阳恒星周围有无和我们地球一样的宜居的行星，我们称之地球2.0，并进一步探明它们上面有无生命迹象。在这个报告中，我将首先介绍目前国际上在搜寻类地球的宜居星方面的进展，也包括我的研究团队的最新研究结果。然后我将介绍我们最近发展起来的“超级开普勒”空间卫星项目。这个项目将用七个直径为30cm的望远镜构成一个大约1800平方度总视场（开普勒视场的17倍）的卫星载荷。她将在2025-2029年期间对准开普勒及其附近的天区，持续四年监测这个视场中大约二十万颗类太阳恒星，并通过把数据和开普勒的数据衔接, 用8年的时间基线来提高凌星信号的信噪比，最大地提高发现地球2.0的机会。我们的最核心科学目标是第一次探测到地球2.0和确定这类行星的发生率。然而，由于这类行星产生的信号极其微弱，这不光对用空间凌星方法探测到它们极具挑战，也对地面后续跟踪观测带来极大的困难。我们的研究表明我们需要未来地面30米望远镜和高稳定，高精度和高色散光学光谱仪来核实这些宜居星的存在，和测量这类宜居星的质量和密度，并因此判断它们是否真的适合生命生存。更具体地讲，中国团队领导的超级开普勒空间卫星加上国际30米望远镜（TMT）的高色散光学光谱仪（HROS）将是下一代搜寻地球2.0的最独特和最强大的天文设备。这些设备的投入使用将帮助人类回答“我们是否是宇宙中唯一的智慧生命？”“我们是从哪里来？”的最基本的问题。  

　　报告时间：2019年10月29日下午2:00   

　　报告地点：紫金山天文台3-302会议室 

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紫金山天文台学术委员会