Bubble Nebula

NGC 7635, the Bubble Nebula in Cassiopeia. The Bubble is approximately 11,000 light years distant, and is approximately 10 light years in diameter. The stellar wind of the massive Wolf-Rayet star BD+602522 is pushing the gas shell of the nebula outward, but the outward movement is being resisted by the nearby dense molecular cloud. This interaction causes the surrounding material to heat up and glow. This image was taken using standard broadband red, green and blue color filters, and as a result has a more normal color appearance than some images of this object taken using narrowband filters.

Eagle Nebula

Eagle Nebula (NGC 6611 or Messier 16) is part of a larger emission nebula (IC 4703) and is a region of active star formation about 6500 light years from Earth in the constellation Serpens. It has been made famous by the Hubble Space Telescope image of the region and dubbed the "Pillars of Creation" since astronomers learned so much about the process of star formation from this source’s data. Inside the dark areas of the pillars are dense, cold gases that are contracting gravitationally, heating up the gas as it collapses to form massive young stars. The intense UV radiation from these many hot, young stars is ionizing hydrogen gas which we see as the red glow surrounding the dark regions.

Cocoon Nebula

The Cocoon Nebula (IC 5146) is a region of newly forming cluster of stars about 15 light years wide some 4000 light years from Earth in the constellation Cygnus. It exhibits all three types of nebulosity: emission, reflection, and absorption. We see the emission nebulosity in the visible portion of the electromagnetic spectrum as a red glow from ionized hydrogen gas excited by young, hot stars. The blue, dust-reflected nebulosity around the edges is caused by scattering of light (preferentially blue light) which traces the boundary of the otherwise invisible molecular cloud. The cold gas and dust of the molecular cloud (temperature is 50 to 100 K) is the soup of material from which the massive stars form, and the absorption of the light by gas and dust can be seen as the dark dust lanes cutting through the image.