12.9μ mosaic of the Ney-Allen Nebula. The white bar corresponds to 10". Image: 3.6-m ESO telescope on La Silla
The Ney-Allen Nebula is an extended infrared source in the Trapezium region of the Orion Complex that shows a strong 10-micron emission feature assumed to result from circumstellar shells of silicate dust. Most of the emission is from dust grains at 250–300 K (about room temperature), in the form of both diffuse clouds and concentrated clumps. Many of the clumps correspond to the protoplanetary disk sources that have been imaged by the Hubble Space Telescope. The dust grains are heated partly by the nearby star Theta-1 Orionis C.