The Bubble Nebula is an Emission Nebula found in the constellation Cassiopeia. An emission nebula is a cloud of ionized gas that emits light, most commonly caused by ultraviolet photons that have excited the gas and caused it to glow. This object was discovered by Charles Wolf and George Rayet, and it is 7,800 light years away - 6 light years in diameter. The brightest star seen within the bubble is SAO 20575, and it is the reason for the bubble shape. It is a Wolf-Rayet star - an O-type star that is nearing the supernova stage. It releases a significant portion of its mass at this stage, and it also has an enormous output of energy and solar wind, which affects the molecular cloud surrounding it.
As seen in the photo above, the bubble is surrounded by a red cloud. This is a cloud of hydrogen gas. It is red because of the fact that it is hydrogen, but the darker areas are caused by clouds of dust covering the hydrogen gas. The large, blue star seen to the right of the bubble is a star that was formed by the dust released from the energy output of the Wolf-Rayet star that caused the bubble.
Snyder, Bill. "NGC7635 Bubble Nebula." Bill Snyder AstroPhotography. <http://billsnyderastrophotography.com/?page_id=1602>.
"The Bubble Nebula." AstroImages. <http://www.astroimages.org/ccd/ngc7635.html>
|Right Ascension (J2000)||23:20:44.9|
|Filters used||B (Blue), C (Clear), R (Red), V (Green)|
|Exposure time per filter||B, C, R, and V 60s|
|Date observed||October 13, 2011|