摘要： Exoplanet atmospheres may carry chemical imprints (e.g. metallicity, C/O ratio) to link to planet formation and evolution history. In the past ten years, transmission spectroscopy has become the most efficient technique to unveil composition, chemistry, structure, and dynamics for exoplanet atmospheres. HST/WFC3 has revealed that a large collection of exoplanets exhibits the water absorption signature at 1.4 micron. However, the determination of water abundances is somewhat hindered by the potential presence of clouds and hazes owing to the degeneracy between pressure and abundance. Fortunately, low-resolution optical spectroscopy can help disentangle this degeneracy and also mitigate contamination from stellar surface heterogeneity. On the other hand, spectroscopy at high-resolution is capable of resolving the fine structure of absorption lines from atoms and ions in the upper atmosphere, offering the opportunity to study atmospheric heating and dynamics. In this talk, I will present the latest results from our transit spectroscopy survey using the low-resolution optical spectrograph at the 10.4 m GTC telescope. This survey has revealed a variety of cloudy, hazy, and clear alien worlds. In particular, I will highlight the role of alkali metals in characterizing exoplanet atmospheres. Furthermore, I will present our recent efforts to resolve the absorption line cores of hydrogen, helium, and alkali metals using high-precision Doppler spectrographs (e.g. HARPS-N, CARMENES, ESPRESSO), which hopefully can reveal the underlying physical and chemical processes.

　　陈果，紫金山天文台副研究员。2004-2008年就读于南京大学天文学系并获得学士学位，2008-2014年在紫金山天文台硕博连读并获得博士学位（其中2010-2012年在德国海德堡马普天文研究所联合培养），2015-2018年在西班牙加纳利天体物理研究所做博士后。主要研究方向是系外行星及其大气的观测刻画。