Inverted bubbles and donut bubbles

Image from the Milky Way Project. This is an “inverted bubble”. A bubble is a nebula that got its shape with the help of massive stars (see MWP about page). An inverted bubble is a bubble where the Polycylic aromatic hyrocarbons (PAHs) did not get destroyed by the strong UV-radiation of the stars, like in… Continue reading Inverted bubbles and donut bubbles