Trifid

Trifid is a type of nebula, a vast cloud of gas and dust in space, that is visible in the constellation Sagittarius. It is located approximately 5,200 light-years away from Earth. The nebula is named for its distinctive appearance, which is composed of three distinct parts: a red emission nebula, a blue reflection nebula, and a dark nebula that obscures the light behind it. The red emission nebula is caused by the ionization of hydrogen gas by the nearby star HD 164492, while the blue reflection nebula is caused by the scattering of light from the same star by dust particles. The dark nebula, known as Barnard 85, is a dense cloud of dust that blocks the light from the stars behind it. Trifid is a popular target for amateur astronomers due to its striking appearance and relative proximity to Earth. It is also a site of active star formation, with several young stars and protostars embedded within the nebula. The nebula was first discovered by the French astronomer Charles Messier in 1764, who cataloged it as Messier 20.