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Starts With A Bang

Mostly Mute Monday: Amazing Final Images Of Stars Right Before They Die

Our Sun will someday become a red giant, and then a planetary nebula + white dwarf combination. Here’s what lies between.

“It will be found that those contained in one article [class of nebulae], are so closely allied to those in the next, that there is perhaps not so much difference between them, if I may use the comparison, as there would be in an annual description of the human figure, were it given from the birth of a child till he comes to be a man in his prime.” –William Herschel

The future of our Sun is very clear: someday it will run out of hydrogen in its core, expand into a red giant, where it will fuse helium until it runs out of that. Afterwards, it blows off its outer layers, forming a planetary nebula, while its core contracts down to a white dwarf.

Image credit: ESA / NASA and the hubble Legacy Archive, created by Judy Schmidt.

This fate, common to all Sun-like stars, affects stellar masses between 40% and 800% of the Sun’s. But the images here aren’t of planetary nebulae, but of a brief, special stage just before it: a preplanetary (or protoplanetary) nebula.

Image credit: NASA / JPL.

At the end of the giant phase, stars begin to blow off their outer (hydrogen) layers, a process that causes the star’s temperature to rise, as hydrogen still fuses in a star’s shell.

Image credit: ESA/Hubble & NASA.

The central star becomes bluer and hotter, giving rise to intense winds.

Image credit: ESA and NASA.

These winds can cause a bipolar or knotted jets, as well as bow shocks.

Image credit: ESA / NASA / Hubble / JPL.

As the star heats up to over 30,000 K, the surrounding ejecta become ionized, creating emission and reflection phenomena together.

Image credit: ESA / Hubble and NASA.

The preplanetary phase is brief (~10,000 years), but so common that we have dozens of examples in our galaxy alone.

Images credit: ESA / Hubble & NASA.

Mostly Mute Monday tells the story of a single astronomical phenomenon or object in visuals, images, video and no more than 200 words.

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