is about "45 times more massive than our sun," and the bubble feature -- called the Bubble Nebula -- is formed by gas escaping from the star's outer layers, pushed outward by the stellar wind at 4 ...

Helix Nebula: This a planetary nebula, which is formed when a star like the Sun runs out of fuel, expands and its outer layers puff off, and then the core of the star shrinks. Orion Nebula ...