A large and bright nebula, 1350 l.y. away in the constellation Orion; also known as M42 or NGC 1976. The nebula covers more than 1° × 1° of sky and is faintly visible to the naked eye as a fuzzy patch around the multiple star Theta1 Orionis, also known as the Trapezium. The ultraviolet light from the Trapezium stars, particularly Theta1 C (spectral type O6), ionizes the nebula. The Orion Nebula is over 20 l.y. in diameter, and contains several hundred solar masses of ionized gas. It forms a hot blister on the near side of one of the massive Orion Molecular Clouds.
Subjects: Astronomy and Astrophysics.