Interaction between M31 and its satellite M32. Gray fuzz is the old stellar component, red circles represent the ISM, star formation/supernova events are bright white circles and the newly-formed stars are the smaller white circles. The passage of M32 through the disk triggers star formation at the observed location of NGC 206 and opens a hole in the disk at the observed location of a hole in the dust emission. Credit: Jeremy Bailin, Paul Bourke, and Karl Gordon.
Movie: M31M32.mov