Shields up, Captain! There’s an unidentified entity ahead! On second thought, no need to take evasive action — this particular space blob is just the glowing remains of a sun-like star, 3,300 light-years away.
Although it looks like something you might find on the viewscreen of the Enterprise (or under the scrutiny of a microbiologist) planetary nebula IC 1295 is actually a very real, very large cosmic object: the expelled outer layers of a star that has reached the end of its life.
The image above, acquired by the European Southern Observatory’s VLT array in Chile’s high, dry Atacama desert, is the most detailed picture of it ever made.
Planetary nebulae — so-called because of their resemblance to actual planets in early telescopes — are created when stars with similar mass as our sun (up to about 8 solar masses) run out of fuel during the final stages of their life cycles. Violent internal convulsions within the failing star blows its outer layers into space, and when the outwardly-expanding shells of material are struck by the star’s radiation they become ionized. This causing them to radiate various wavelengths of energy, depending on the various elements present.
In IC 1295′s case there’s a large amount of oxygen in the shells which, when ionized, glows green — something that also happens in aurorae seen here on Earth.
But while the northern and southern lights are transient and fleeting, planetary nebulae last for quite a bit longer — these stellar remains glow for several tens of thousands of years. But eventually even they will dissipate and fade, leaving the white dwarfs at their centers to grow cooler and dimmer and, after about 10 billion years or so, become dark, dense lumps of carbon — black dwarfs, the ultimate ends of sun-like stars.
But as they fade into that good night they certainly do not go quietly, allowing us to marvel at amazing views like this!
Image credit: ESO