A catalog of white light coronal mass ejections observed by the SOHO spacecraft

Abstract

The Solar and Heliospheric Observatory (SOHO) mission's white light coronagraphs have observed nearly 7000 coronal mass ejections (CMEs) between 1996 and 2002. We have documented the measured properties of all these CMEs in an online catalog. We describe this catalog and present a summary of the statistical properties of the CMEs. The primary measurements made on each CME are the apparent central position angle, the angular width in the sky plane, and the height (heliocentric distance) as a function of time. The height‐time measurements are then fitted to first‐ and second‐order polynomials to derive the average apparent speed and acceleration of the CMEs. The statistical properties of CMEs are (1) the average width of normal CMEs (20° < width ≤ 120°) increased from 47° (1996; solar minimum) to 61° (1999; early phase of solar maximum) and then decreased to 53° (2002; late phase of solar maximum), (2) CMEs were detected around the equatorial region during solar minimum, while during solar maximum CMEs appear at all latitudes, (3) the average apparent speed of CMEs increases from 300 km s −1 (solar minimum) to 500 km s −1 (solar maximum), (4) the average apparent speed of halo CMEs (957 km s −1 ) is twice of that of normal CMEs (428 km s −1 ), and (5) most of the slow CMEs ( V ≤ 250 km s −1 ) show acceleration while most of the fast CMEs ( V > 900 km s −1 ) show deceleration. Solar cycle variation and statistical properties of CMEs are revealed with greater clarity in this study as compared with previous studies. Implications of our findings for CME models are discussed.