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

Coronal mass ejections (CMEs) are powerful eruptions of plasma and magnetic fields that play a significant role in stellar mass loss and influence the habitability of exoplanets. Observations of stellar flares without corresponding CME signatures suggest that a non-negligible fraction of stellar CMEs may be confined, likely due to their inability to escape the star’s strong magnetic constraints. Successful stellar CMEs, however, can be extraordinarily energetic, emphasizing the need to differentiate between erupted and confined events and identify their distinct signatures. Here, we investigate the dynamics of successful versus confined CMEs under the Sun-as-a-star framework and extend these insights to stellar cases. We employ the Alfven Wave Solar Model (AWSoM) to perform global magnetohydrodynamic (MHD) simulations using SDO/HMI synoptic magnetograms and initiate CMEs with Titov-Demoulin (TD) flux ropes. Realistic spectral lines are synthesized using the SPECTRUM code to analyze spectral responses. Coronal dimming is used as a diagnostic proxy for CMEs. We also developed a method of automated detection, fitting, and template matching for a multi-component spectrum, where strong “clean” spectral lines that are usually well separated may now be blended because of large Doppler shifts. To extend this analysis to stellar environments, we enhance the input magnetic flux and the flux ropes’ initial magnetic energies. Preliminary results demonstrate the utility of spectral diagnostics in identifying and characterizing stellar CMEs, potentially providing observers with signatures to distinguish between erupted and confined events.