Authors: Tong Shi (SETI Institute), Meng Jin (Lockheed Martin Solar and Astrophysics Lab), Xianyu Liu (University of Michigan)

Coronal Mass Ejections (CMEs) on the Sun and active stars drive severe space weather, yet identifying true macroscopic eruptions from disk-integrated stellar observations remains challenging. In this study, we present a comparative 3D magnetohydrodynamic (MHD) simulation of erupted and confined CMEs to evaluate photometric and spectral observational proxies. Utilizing BATSRUS/AWSoM initiated with Titov-Demoulin flux ropes, we simulate a successful 1500 km/s fast eruption and a failed/confined eruption. We synthesize the corresponding EUV light curves and idealized high-resolution spectra using the SPECTRUM module. Full-disk and active-region-limited integrations demonstrate that deep, sustained EUV dimming serves as a robust proxy for large-scale mass evacuation in the erupted case, contrasting with the transient fluctuations of the confined case. However, the extreme kinematics of the erupting CME produce severely blended, multi-component spectral lines, rendering traditional manual line-fitting intractable. To address this, we introduce a novel automated spectral fitting pipeline alongside a statistical template-matching method. By cross-referencing automatically extracted multi-thermal peaks against a CHIANTI rest-wavelength reference, we systematically tackle the resulting line-identification degeneracy problem. This statistical approach successfully extracts the high-velocity shock-heated component and a secondary bulk plasma core kinematics directly from the highly complex synthesized spectrum. By demonstrating that Doppler velocity can be statistically reconstructed from heavily blended spectra, this methodology provides insight for identifying and characterizing highly energetic stellar CMEs from purely integrated observational data. Therefore, this bridging of high-fidelity solar modeling with automated spectral analysis offers a robust pathway for advancing exoplanetary space weather and stellar CME detection.