Fast Mid-IR flashes detected during small solar X-Ray bursts

CASSIANO, MARTA M.; KAUFMANN, PIERRE; MARCON, ROGÉRIO; KUDAKA, AMAURI S.; MARUN, ADOLFO; GODOY, RODOLFO; PEREYRA, PABLO; MELO, ARLINE M.; LEVATO, HUGO

SOLAR PHYSICS

SPRINGER

Año: 2010 vol. 264 p. 71 - 79

0038-0938

Solar observations in the mid-infrared 8-14 μm band continuum were carried out with cadence of 5 frames per second, in December 2007. Rapid small heated sources, with a 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 photometric beam of 25 arc sec. The 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 represented a temperature enhancement of 50-150 K. © 2010 Springer Science+Business Media B.V.