Pinwheel nebula
A pinwheel nebula is a class of Wolf–Rayet nebula in the shape of a pinwheel.
Wolf–Rayet nebulae
Some Wolf–Rayet stars are surrounded by pinwheel nebulae. These nebulae are formed from the dust that is spewed out of a binary star system. The stellar winds of the two stars collide and form two dust lanes that spiral outward with the rotation of the system.The first such nebula, located around WR 104, was discovered using the Keck Observatory in 1999. The discovery of a second, WR 98a, established pinwheel nebulae as a distinct class of nebula.