Discovered by William Herschel in 1780

NGC 1857 is an open cluster of stars located in the constellation of Auriga.  The large yellow-orange star in the center of the image is classified as a K5III yellow giant star.  This type of star has exhausted its supply of hydrogen fuel in its core and has started fusing helium.  Additional energy is be produced by fusing hydrogen in a shell surrounding the core.  K5III giant stars have moved off the main sequence line of the Hertzsprung-Russell diagram and entered an unstable line in its progression to a probable super-nova death.