Emission Height and Temperature Distribution of White-Light Emission Observed by Hinode/SOT from the 2012 January 27 X-class Solar Flare

TL;DR

This study analyzes white-light emissions during a 2012 solar flare, revealing their emission heights, temperature distribution, and implications for particle penetration into the solar atmosphere.

Contribution

It provides the first detailed height and temperature distribution analysis of white-light emissions during a solar flare using Hinode/SOT data.

Findings

White-light emissions occur at the lowest levels of Ca II H emission.

Different wavelengths originate from progressively lower heights.

Lower-layer emissions exhibit higher temperatures.

Abstract

White-light emissions were observed from an X1.7 class solar flare on 27 January 2012, using three continuum bands (red, green, and blue) of the Solar Optical Telescope (SOT) onboard the Hinode satellite. This event occurred near the solar limb, and so differences in locations of the various emissions are consistent with differences in heights above the photosphere of the various emission sources. Under this interpretation, our observations are consistent with the white-light emissions occurring at the lowest levels of where the Ca II H emission occurs. Moreover, the centers of the source regions of the red, green, and blue wavelengths of the white-light emissions are significantly displaced from each other, suggesting that those respective emissions are emanating from progressively lower heights in the solar atmosphere. The temperature distribution was also calculated from the white-light data, and we found the lower-layer emission to have a higher temperature. This indicates that high-energy particles penetrated down to near the photosphere, and deposited heat into the ambient lower layers of the atmosphere.