A Statistical Study of Solar Sources of Wide Coronal Mass Ejections in 2011

Solar surface signatures of coronal mass ejections (CMEs) are flares, filament eruptions/disappearances, EUVI waves, dimmings, and post-eruption arcades. After the SDO launch we have an excellent opportunity to investigate the solar sources of CMEs because of the high spatial- and temporal-resolution images from SDO/AIA and multiple views from SOHO, SDO, and STEREO-A/B. We examined the solar sources of all wide CMEs (width ≥ 60°) observed by either SOHO/LASCO or STEREO/SECCHI in 2011. Out of the 597 wide CMEs identified, 322 (54%) were associated with active region flares (FLs) and 164 (27%) with eruptive quiescent prominences (EPs). In 88 cases (15%) only EUV dimmings (DIMs) were observed. For the remaining 23 (4%) CMEs we were not able to identify the solar sources (UNK), i.e. they were stealth CMEs. The average speed and width of the CMEs are, 481 km/s and 115° for FLs, 349 km/s and 90° for EPs, 270 km/s and 78° for DIMs, and 171 km/s and 90° for UNKs, respectively. According to Ma et al. (2010), one third of CMEs observed by STEREO-A/B from 2009 Jan. 1 to Aug. 31 was categorized as stealth CMEs. Our study shows that the rate of stealth CMEs is much smaller for wide CMEs. We also compared the average appearance latitude of CMEs between the stealth and all wide CMEs and found that the stealth CMEs appeared from higher latitude (48°) than the general population (35°). Reference: Ma et al. (2010) ApJ, 722, 289