Initiation and early evolution of the Coronal Mass Ejection on May 13, 2009 from EUV and white-light observations

TL;DR

This study provides detailed multi-wavelength observations of the initiation and early evolution of a CME on May 13, 2009, from the solar surface to 15 solar radii, revealing its formation, associated prominence, and kinematic phases.

Contribution

It offers a comprehensive analysis of CME initiation, early development, and trajectory using combined EUV and white-light data, supporting the CME breakout model.

Findings

CME formed as a U-shaped structure close to the magnetic X-point.

Associated prominence was located at the bottom of the U-shape, not above.

CME mass increased over time and its trajectory curved toward the ecliptic plane.

Abstract

We present the results of the observations of a coronal mass ejection (CME), which occurred on May 13, 2009. The most important feature of these observations is that the CME was observed from the very early stage (the solar surface) up to a distance of 15 solar radii ($R_\odot$). Below 2 $R_\odot$, we used the data from the TESIS EUV telescopes obtained in the Fe 171 A and He 304 A lines, and above 2 $R_\odot$, we used the observations of the LASCO C2 and C3 coronagraphs. The CME was formed at a distance of 0.2-0.5 $R_\odot$from the Sun's surface as a U-shaped structure, which was observed both in the 171 A images and in white-light. Observations in the He 304 A line showed that the CME was associated with an erupting prominence, which was located not above-as predicts the standard model-but in the lowest part of the U-shaped structure close to the magnetic X-point. The prominence location can be explained with the CME breakout model. Estimates showed that CME mass increased with time. The CME trajectory was curved-its helio-latitude decreased with time. The CME started at latitude of 50$^{\circ}$ and reached the ecliptic plane at distances of 2.5 $R_\odot$. The CME kinematics can be divided into three phases: initial acceleration, main acceleration, and propagation with constant velocity. After the CME onset GOES registered a sub-A-class flare.