Prominence eruption observed in He II 304 {\AA} up to $>6 R_\sun$ by EUI/FSI aboard Solar Orbiter

TL;DR

This paper reports the first observation of a prominence eruption in He II 304 Å emission extending beyond 6 solar radii, combining multi-viewpoint data to analyze its kinematics and radiative properties.

Contribution

It presents the first observation of a prominence in He II 304 Å at heights over 6 solar radii, with detailed 3D reconstruction and multi-passband analysis.

Findings

Prominence and CME speeds are approximately 1700 km/s and 2200 km/s.

Parts of the prominence are observed up to over 6 solar radii.

He II emission is likely produced by collisional excitation.

Abstract

We report observations of a unique, large prominence eruption that was observed in the He II 304 {\AA} passband of the the Extreme Ultraviolet Imager/Full Sun Imager telescope aboard Solar Orbiter on 15-16 February 2022. Observations from several vantage points (Solar Orbiter, the Solar-Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and Earth-orbiting satellites) were used to measure the kinematics of the erupting prominence and the associated coronal mass ejection. Three-dimensional reconstruction was used to calculate the deprojected positions and speeds of different parts of the prominence. Observations in several passbands allowed us to analyse the radiative properties of the erupting prominence. The leading parts of the erupting prominence and the leading edge of the corresponding coronal mass ejection propagate at speeds of around 1700 km/s and 2200 km/s, respectively, while the trailing parts of the prominence are significantly slower (around 500 km/s). Parts of the prominence are tracked up to heights of over $6 R_\sun$. The He II emission is probably produced via collisional excitation rather than scattering. Surprisingly, the brightness of a trailing feature increases with height. The reported prominence is the first observed in He II 304 {\AA} emission at such a great height (above 6 $R_\sun$).