Astr110 Photography Projects, Fall 2005

Cocoon Nebula (IC5146), Jackford B. Kolk

The Cocoon Nebula is located in the constellation of Cygnus in the night sky. Nebulae are clouds of gas and dust floating about in space. The material in this nebula is in the process of coalescing to form stars of various sizes and densities. Because of this, another term for a nebula like this is a stellar nursery. The Cocoon Nebula is roughly 5,000 lightyears from Earth and approximately 10 lightyears in diameter.

The Cocoon Nebula primarily consists of large amounts of hydrogen gas which emit photons (red light) as the electrons in the hydrogen atoms drop to lower orbits of their nuclei (usually from level 3 to level 2). The lighter areas are reflecting blue light from nearby stars that is being thrown off course as it comes in contact with the hydrogen and interstellar dust in the nebula. In some areas, the nebula is so dense that it is absorbing the light of stars behind it, which is why those areas have significantly less visible stars in them (in this picture those areas are above the nebula, to the right of it just below the middle of the picture, and in the bottom left corner).

References:
www.starrywonders.com/cocoon.html, and Astromoy 110 Lectures by Professor Deborah Haarsma.