Sun-as-a-star observations of obscuration dimmings caused by filament eruptions

TL;DR

This study analyzes sun-as-a-star observations of filament eruptions causing dimming signatures in flux curves, providing insights into stellar filament eruptions and their properties, which are difficult to detect directly on other stars.

Contribution

The paper presents detailed analysis of six solar filament eruptions and their dimming signatures, offering a new method to infer filament properties in stellar observations.

Findings

Dimming depths ranged from 1% to 6.2%.

Dimming durations varied from 0.4 to 7 hours.

Positive correlation between dimming depth and area.

Abstract

Filament eruptions often lead to coronal mass ejections (CMEs) on the Sun and are one of the most energetic eruptive phenomena in the atmospheres of other late-type stars. However, the detection of filament eruptions and CMEs on stars beyond the solar system is challenging. Here we present six filament eruption cases on the Sun and show that filament material obscuring part of the solar disk can cause detectable dimming signatures in sun-as-a-star flux curves of He II 304 A. Those filament eruptions have similar morphological features, originating from small filaments inside active regions and subsequently strongly expanding to obscure large areas of the solar disk or the bright flare regions. We have tracked the detailed evolution of six obscuration dimmings and estimated the dimming properties, such as dimming depths, dimming areas, and duration. The largest dimming depth among the six events under study is 6.2% accompanied by the largest dimming area of 5.6\% of the solar disk area. Other events have maximum dimming depths in a range of around 1% to 3% with maximum areas varying between about 3% to 4% of the solar disk area. The duration of the dimming spans from around 0.4 hours to 7.0 hours for the six events under study. A positive correlation was found between the dimming depth and area, which may help to set constraint on the filament sizes in stellar observations.