Discovery of multi-temperature coronal mass ejection signatures from a young solar analogue

Abstract Coronal mass ejections (CMEs) on the early Sun may have profoundly influenced the planetary atmospheres of early Solar System planets. Flaring young solar analogues serve as excellent proxies for probing the plasma environment of the young Sun, yet their CMEs remain poorly understood. Here we report the detection of multi-wavelength Doppler shifts of the far-ultraviolet and optical lines during a flare on the young solar analogue EK Draconis. During and before a Carrington-class (~10 32 erg) flare, warm far-ultraviolet lines (~10 5 K) exhibited blueshifted emission at 300–550 km s −1 , indicative of a warm eruption. Then, 10 min later, the Hα line showed slow (70 km s −1 ), long-lasting (≳2 h) blueshifted absorptions, indicating a cool (~10 4 K) filament eruption. This provides evidence of the multi-temperature and multi-component nature of a stellar CME. If Carrington-class flares or CMEs occurred frequently on the young Sun, they may have cumulatively impacted the early Earth’s magnetosphere and atmosphere.