Authors: Zihao Yang (Peking University; NCAR/HAO), Hui Tian (Peking University), Xianyong Bai (NAOC), Yajie Chen (Peking Univerisity), Yang Guo (Nanjing University), Yingjie Zhu (University of Michigan, Ann Arbor), Yu Xu (Peking Univerisity), Yuhang Gao (Peking Univerisity), Hechao Chen (Peking Univerisity), Jiale Zhang (Peking Univerisity))

Coronal mass ejections (CMEs) are the largest-scale eruptive phenomena in the solar system. Associated with enormous plasma ejections and energy release, CMEs have an important impact on the solar-terrestrial environment. CMEs can also occur on other stars and will greatly impact the habitability of the orbiting exoplanets around the hosting stars. Therefore, the detection of stellar CMEs and how stellar CMEs affect the space environments are indispensable when evaluating the habitability of exoplanets. Observationally, solar CMEs could result in the asymmetries of spectral line profiles. However, few studies have concentrated on whether we can detect solar and stellar CME signals and accurately diagnose CME properties through line profile asymmetries. In this work, we constructed a geometric CME model and derived the analytical expressions for full-disk integrated extreme ultraviolet (EUV) line profiles during CMEs. For different CME properties and instrumental conditions, full disk-integrated line profiles were synthesized. We further evaluated the detectability and diagnostic potential of CMEs from the synthetic line profiles. Our investigations provide important constraints on the future design of spectrographs for solar and stellar CME detections through EUV line asymmetries.