摘要
寻找地外生命是人类探索宇宙的核心目标之一.为实现这一目标,理解恒星及其周围宜居行星的联系非常关键.近年来,越来越多的学者意识到,空间天气的现象(即类似太阳活动对地球空间环境的影响)在太阳系外的恒星-行星系统中也存在.作为系外空间天气的主要源头,宿主恒星(主要是晚型主序恒星)的星冕及其磁活动所产生的电磁和粒子辐射可改变行星大气成分、导致行星大气逃逸、损害生物组织,进而影响系外行星上生命的起源与存续.然而,当前我们对星冕的了解极其匮乏,这严重制约了相关研究.本文建议尽快对宿主恒星的星冕及其活动规律进行全面、有效的监测.要实现这一目标,亟需建造新一代的极紫外和软X射线望远镜,在大约1–350?的波段(特别是170–285?和90–140?的极紫外波段)对少数邻近太阳系的、不同光谱型的宿主恒星(包括但不限于一部分已知潜在宜居行星的宿主恒星)开展长期、连续的光谱和测光观测.本文阐述了这些观测的详细科学目标,并提出了技术指标需求和初步的探测方案.利用这些观测,有望确切地探测到星冕物质抛射、冕洞和活动区冕环系统等大尺度结构,实现星冕磁场的常规测量,并极大地丰富我们对恒星耀斑和星冕等离子体性质的认识.此外,通过观测系外行星“凌星”期间该波段辐射的变化,还有望获得行星大气、电离层和磁层等关键信息.基于这些观测,将能实质性地推动太阳系外的空间天气研究,并准确评估其在宜居世界形成过程中的作用.
Searching for extraterrestrial life is one of the most important targets for exploration of the universe. To achieve this goal,it is of critical importance to understand the connection between host stars(mainly cool dwarf stars) and habitable exoplanets. In recent years, more and more researchers have realized that the space weather phenomenon(i.e., solar activity and its impact on the Earth space environment) should also exist in star-planet systems beyond the solar system.As the main sources of space weather, various types of magnetic activity in host stars’ coronae can produce strong electromagnetic and particle radiation that could damage biological tissues, change the chemical composition and lead to the erosion of the planetary atmospheres, thus affecting the origin and survival of life. However, our understanding of the stellar coronae is very limited, which greatly hampers our understanding of the impact of space weather on habitability.Thus, we suggest effectively probing the physical parameters of the coronae and monitoring various types of coronal activity of host stars as soon as possible. To achieve this, we need to build next-generation dedicated EUV and X-ray(1–350 ?, most importantly 170–285 ? and 90–140 ?) telescopes to perform long-term and continuous spectroscopic and photometric observations of nearby host stars(including but not limited to the host stars of some potentially habitable exoplanets). We describe detailed scientific objectives for such observations, propose the required technical specifications to achieve these scientific goals, and provide preliminary designs of the optical systems. With these telescopes, we could unambiguously detect stellar coronal mass ejections, probe large-scale coronal structures such as coronal holes and active region loop systems, routinely measure the coronal magnetic field, and largely enrich our understanding of stellar flares and coronal plasma properties. By monitoring changes in the stellar emission during exoplanet transits, we may also inf
作者
田晖
白先勇
邓元勇
李文显
陈亚杰
杨子浩
徐昱
陈何超
刘贤雨
TIAN Hui;BAI XianYong;DENG YuanYong;LI WenXian;CHEN YaJie;YANG ZiHao;XU Yu;CHEN HeChao;LIU XianYu(School of Earth and Space Sciences,Peking University,Beijing 100871,China;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China)
出处
《中国科学：物理学、力学、天文学》
CSCD
北大核心
2022年第11期127-144,共18页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家重点研发计划(编号:2021YFA0718600,2021YFA1600500)资助项目。
关键词
晚型恒星
极紫外辐射
X射线辐射
系外行星
系外空间天气
late-type star
extreme ultraviolet radiation
X-ray radiation
exoplanet
exoplanetary space weather
