M43
Messier 43 (M43), also known as De Mairan's Nebula, is a small emission nebula in the constellation Orion. It lies adjacent to the brighter Orion Nebula (M42) and is part of the same star-forming complex, the Orion Molecular Cloud. M43 appears as a distinct glow with fainter surrounding gas, and is visually connected to M42 by shared nebulosity in wide-field images.
Distance and size: M43 is at roughly the same distance as the Orion Nebula, about 1,300 to
Illumination and composition: The nebula is primarily hydrogen gas ionized by a nearby hot, young star, giving
Observation: M43 is accessible to amateur astronomers and is often observed in the same field of view
History: The object was cataloged by Charles Messier in 1771 as part of his deep-sky survey. It
Astronomy context: As part of the Orion complex, M43 contributes to understanding high-mass star formation and