Fast Mid-IR Flashes Detected During Small Solar X-Ray Bursts

TL;DR

This study reports the detection of rapid mid-infrared brightness flashes during a small solar X-ray burst, revealing small heated sources on the Sun's surface with high temporal resolution.

Contribution

First observation of fast mid-infrared flashes associated with weak solar X-ray bursts, providing new insights into solar flare dynamics in the mid-infrared spectrum.

Findings

Detected rapid brightness temperature enhancements of 0.5 to 2.0 K.

Observed fluxes of 30-130 solar flux units.

Identified small heated sources on the Sun during X-ray activity.

Abstract

Solar observations in the mid-infrared 8-14 \mu\m band continuum were carried out with cadence of 5 frames per second, in December 2007. Rapid small heated sources, with typical duration of the order of seconds, were found on the bright plage-like areas around sunspots, in association with relatively weak GOES soft X-ray bursts. This work presents the analysis of fast mid-infrared flashes detected during a GOES B2.0-class event on 10 December 2007, beginning at about 10:40 UT. Rapid brightness temperature enhancements of 0.5 to 2.0 K were detected at the Earth by a microbolometer array, using a telescope with 10.5 cm diameter aperture producing a diffraction limited field-of-view of 25 arcsec. Minimum detectable temperature change was of 0.1 K. The corresponding fluxes are 30-130 solar flux units. At the solar surface the estimated rapid brightenings were of 50-150 K