Butterfly Nebula NGC 2346
The Butterfly Nebula (NGC 2346) is a planetary nebula near the celestial equator of the constellation Monoceros that was first observed by William Hershel in 1795. The nebula's distinct 'double bubble' shape is the result of a very rapid, 30 day orbital period between a blue-white A5 star and the M5 red dwarf remnant of the star that shed its outer layers to form the nebular gas cloud. There is a significant amount of turbulence within the gas cloud that has periodically caused significant changes in the stars' apparent magnitude, such when the system swung between the 11th and 15th magnitude every two weeks for a period of 4 years at the end of the 20th Century.[1]
There are no planetary bodies in the system.