A Giant Starspot on HD 12545

What could cause a star to have such a large spot? Our Sun itself frequently has sunspots , relatively cool dark magnetic depressions that move across its surface. HD 12545 , however, exhibits the largest starspots yet observed. Doppler imaging - the use of slight changes in color caused by the rotation of the star - was used to create this false-color image . The vertical bar on the right gives a temperature scale in kelvins . This giant, binary, RS CVn star , also known as XX Trianguli , is visible with binoculars in the constellation of Triangulum . The starspot is thought to be caused by large magnetic fields that inhibit hot matter from flowing to the surface.