Triangulation of CME Source Region Locations on the Sun and Dependence on Spacecraft Observation Angles

Abstract

STEREO-A, STEREO-B, and LASCO/SOHO observe coronal mass ejections (CMEs) from three different vantage points. On the basis of the radial plane-of-sky (POS) measurements of a CME in these three projection planes, the CME source region (SR) location was determined using the triangulation method of Temmeretal2009. As this triangulation method needs distance-time measurements in one POS as reference input, the determined SR varies with the change of the reference system. In the present study we vary the reference system, which shows the dependence of the resulting SR location of a CME on the spacecraft observation angles, and also reveals the limitation of the radial POS measurements.