  Coronal mass ejections (CMEs) are violent ejections of magnetized plasma from
the Sun, which can trigger geomagnetic storms, endanger satellite operations
and destroy electrical infrastructures on the Earth. After systematically
searching Sun-as-a-star spectra observed by the Extreme-ultraviolet Variability
Experiment (EVE) onboard the Solar Dynamics Observatory (SDO) from May 2010 to
May 2022, we identified eight CMEs associated with flares and filament
eruptions by analyzing the blue-wing asymmetry of the O III 52.58 nm line
profiles. Combined with images simultaneously taken by the 30.4 nm channel of
the Atmospheric Imaging Assembly onboard SDO, the full velocity and propagation
direction for each of the eight CMEs are derived. We find a strong correlation
between geomagnetic indices (Kp and Dst) and the angle between the CME
propagation direction and the Sun-Earth line, suggesting that Sun-as-a-star
spectroscopic observations at EUV wavelengths can potentially help to improve
the prediction accuracy of the geoeffectiveness of CMEs. Moreover, an analysis
of synthesized long-exposure Sun-as-a-star spectra implies that it is possible
to detect CMEs from other stars through blue-wing asymmetries or blueshifts of
spectral lines.
