Stars form by the collapse and coalescence of large molecular clouds. When a young star forms in the cloud, radiation from the young star blows material away from the star, forming a hollow bubble. This article examines cases of these bubbles that have been observed in one example of a large molecular cloud, giving astronomers more insight into the process of star formation.

http://www.raa-journal.org/raa/index.php/raa/article/view/1530