Comprehensive Observations of a Solar Minimum Coronal Mass Ejection with the Solar Terrestrial Relations Observatory

Abstract

We perform the first kinematic analysis of a coronal mass ejection (CME) observed by both imaging and in situ instruments on board the Solar Terrestrial Relations Observatory (STEREO). Launched on 2008 February 4, the CME is tracked continuously from initiation to 1 AU using the imagers on both STEREO spacecraft, and is then detected by the particle and field detectors on board STEREO-B on February 7. The CME is also detected in situ by the Advanced Composition Explorer and Solar and Heliospheric Observatory at Earth's L1 Lagrangian point. This event provides a good example of just how different the same event can look when viewed from different perspectives. We also demonstrate many ways in which the comprehensive and continuous coverage of this CME by STEREO improves confidence in our assessment of its kinematic behavior, with potential ramifications for space weather forecasting. The observations provide several lines of evidence in favor of the observable part of the CME being narrow in angular extent, a determination crucial for deciding how best to convert observed CME elongation angles from Sun-center to actual Sun-center distances.