RCW 120: A Perfect Bubble
Résumé
RCW 120 is a small inconspicuous optical H II region. It is also the archetype of the many bubbles discovered by the Spitzer Space Telescope. What can we learn about star formation in such a simple object? We discuss the distribution of the associated dust material. A layer of neutral material has been collected around the ionized gas during the expansion of the H II region. Many young stellar objects are observed on the border of RCW 120. We discuss their evolutionary states, masses and locations with respect to the cold dust condensations. Different processes of triggered star formation are at work in the collected layer, forming stars of all masses.