NGC 2264, the "Cone Nebula," lies some 2,500 light-years distant in the constellation Monoceros. This 2.5 light-year long section was imaged by Hubble's Advanced Camera for Surveys (ACS) instrument. The entire nebula is around 7 light-years in length.
Like many nebulae of this type, NGC 2264 is an active stellar nursery. The pillar is breaking up due to radiation from active young stars (beyond the top of the image). The region surrounding the pillar appears to glow red because ultra-violet (U-V) radiation is heating the pillar, causing gas to drift away into nearby space, where more U-V radiation excites the hydrogen molecules and causes the gas to glow. As this process continues, the Cone will break up into smaller segments, eventually leaving only small dense pockets of gas and dust.
