Hubble catches a stellar garden sprinkler

As stars die, they form the most beautiful objects in the cosmos. As the star ejects its outer atmosphere into space, it forms a beautiful planetary nebula. Planetary nebulae are like snowflakes: no two are exactly the same. This is for several reasons – the stars that create them can have different masses, sizes, temperatures, and chemical compositions. Moreover, we see different planetary nebulae at different moments in their evolution. Sometimes, they are later stage and we see them fully formed; other times, we see them just as they are beginning to form, much like Hen 3-1475:

Hubble Space Telescope image of Hen 3-1475. Credit: NASA/ESA

Hen 3-1475 is actually a proto-planetary nebula. That is, a planetary nebula in the making! The central star is surrounded by a thick disk of gas and dust, which almost blocks it from our view. Fortunately, it’s tilted just enough such that we can look “down” the disk and catch a glimpse of the star within.

The star is blowing out a fast stellar wind, which is funneled by the disk into a bi-polar outflow at several hundred kilometers per second.  If you look closely at the outflow funnels, you can even see “shock diamonds“, which are compression waves caused by the gas blasting out between 150-200 kilometers per second!

The central star is very bright – more than 12,000 times brighter than our Sun but not yet hot enough to cause the outflowing gas to ionize. Instead, the gas glows by scattering and reflecting starlight inside the funnel. Cool!

Finally, the shape of the outer lobes are curved into an extended “s” shape (or for you math geeks, an integral symbol). That’s because the star is precessing, like a spinning top as it starts to wobble. The star’s precession is only about 1,000 years, causing the outflowing material to “sprinkle” out into space in a gentle s-shaped pattern.

I love this image not just because it’s beautiful, but because it also reflects the same kinds of everyday physics we witness here on earth (ok, maybe not everybody gets to see shock diamonds from jets everyday but you get the picture). It’s a reminder of how some relatively simple laws of physics can give us such intricate and lovely cosmic sculptures.

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