Spiral galaxies

The term 'Pinwheel nebula' is an antiquated misnomer

Misnomer

A misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derive their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...

 used by observers before Edwin Hubble

Edwin Hubble

Edwin Powell Hubble was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than the Milky Way - our own galaxy...

 realized that these spiral shaped nebulae were actually 'island universes'.

Wolf-Rayet nebulae

Some Wolf-Rayet star

Wolf-Rayet star

Wolf–Rayet stars are evolved, massive stars , which are losing mass rapidly by means of a very strong stellar wind, with speeds up to 2000 km/s...

s are surrounded by pinwheel nebulae. These nebulae are formed from the dust that is spewed out of a binary star

Binary star

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...

 system. The stellar winds of the two stars collide and form two dust lanes that spiral outward with the rotation of the system.

External links

• http://www.physics.usyd.edu.au/~gekko/wr104.html Some Wolf-Rayet stars in binaries are close enough that we can image a rotating "pinwheel nebula" showing the dust generated by colliding winds in the binary system, from Aperture Masking Interferometry
  Aperture masking interferometry
  Aperture Masking Interferometry is a form of speckle interferometry, allowing diffraction limited imaging from ground-based telescopes. This technique allows ground based telescopes to reach the maximum possible resolution, allowing ground-based telescopes with large diameters to produce far...
  
  observations.
• Pinwheel Galaxy from ESA/Hubble