A Fragile Cosmic Sphere
The Bubble Nebula is created by the fierce stellar wind from the massive hot star SAO 20575. This star is not at the center of the bubble; instead, it is offset, pushing the gas into a sphere that is being resisted by a dense molecular cloud on one side. The star is roughly 45 times more massive than our Sun, and its radiation is so intense that it 'blows' a hole in the surrounding interstellar medium. The sphere we see is the shock front where the fast-moving stellar wind meets the colder, stationary gas of space.
Imaging Challenges
- • Resolution: The bubble itself is small. To see the 'veins' and surface textures on the sphere, you need perfect focus and sharp processing.
- • Dynamic Range: The central star is very bright, while the edge of the bubble and the surrounding 'Lobster Claw' nebula are much fainter.
- • Framing: Deciding whether to zoom in on the Bubble or go wide to include the open cluster M52.
The Bubble is approximately 7 light-years across—about 1.5 times the distance from our Sun to the nearest star system, Alpha Centauri.