Ultraviolet brightenings in active regions as observed from OSO-8

  title={Ultraviolet brightenings in active regions as observed from OSO-8},
  author={Bruce William Lites and Eldon R. Hansen},
  journal={Solar Physics},
Repeated raster images of solar active regions taken at the line centers of the Si iv and C iv resonance lines using the University of Colorado (CU) ultraviolet spectrometer aboard OSO-8 reveal dramatic transient brightenings of up to factors of 10. These brightenings last several minutes and frequently show a repetitive character. Inspection of simultaneous Hα flare patrol records show that these transition zone events are often associated with subflare-like brightenings in the chromosphere… CONTINUE READING