Friday, Aug 29, 2025

The Cocoon Nebula (Caldwell 19 or IC 5146) is a bright emission and reflection nebula in the constellation Swan, about 4,000 light years from Earth. With a diameter of around 15 light years, it surrounds a young star cluster that is illuminated by newly formed stars. The region shows a mixture of glowing hydrogen gas and interstellar dust, in which new stars continue to form.