A delicate-looking cosmic bubble shape appears to float inside a distant nebula in this stunning view captured by California-based skywatcher Larry Van Vleet .
The photo shows a giant bubble of gas blown by the nebula NGC 7635, also known as the Bubble nebula. Van Vleet used a RCOS 16 Truss telescope and Apogee U16M to capture the photo from his Sierra Remote Observatories in Shaver Lake,Calif., in August.
The bubble was created by fierce stellar winds and intense radiation from a nearby star, which likely has a mass 10 to 20 times that of the sun. The process blasted out material to form the bubble structure of glowing gas against denser material in a surrounding molecular cloud. The cloud contains the expansion of the Bubble nebula while itself being excited by the hot central star, causing it to glow. [Gallery: Strange Nebula Shapes, What Do You See?]
Located 7,100 light-years from Earth in the constellation Cassiopeia, the bubble is about 6 light-years wide and glows pink because of the red, hot gas that surrounds it. Emission nebulas are clouds of high temperature gas. The atoms in the cloud are energized by ultraviolet light from a nearby star and emit radiation as they fall back into lower energy states (in much the same way as a neon light).
The relatively bright star at about the 11 o'clock position within the prominent bubble is known as BD +60°2522 or SAO 20575 and is the source of the bubble shape.
The star is known as a Wolf-Rayet star, which is an O-type star that is nearing the supernova stage. These stars are incredibly hot — from 25,000 to 50,000 Kelvin (about 24,726 degrees Celsius or 44,540 degrees Fahrenheit) and expel their outer layers of gas at tremendous velocities (thousands of kilometers per second).
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