The answer is; sunspots, photosphere.
Sunspots are cooler than the rest of the surface of the sun hence their appearance of being darker than the rest of the photosphere. The photosphere is the outer sun’s shell that emits radiation to space. These sunspots are associated with increased magnetic influx that is accompanied by coronal mass ejection. It is thought that these magnetic fluxes hinder efficient convection currents in the regions.