Star with spiral arms spotted by astronomers

Here’s something new – a star with spiral arms. We’ve all seen galaxies with spiral arms. Our own home galaxy, the Milky Way, has them. But a star with spiral arms? That’s something astronomers have never seen before. But no surprise. After all, nature loves spirals.

The star is SAO 206462. It appears to be a relatively young star surrounded by a disk of gas and dust in a spiraling shape. A team led by Carol Grady – using Japan’s Subaru Telescope in Hawaii – spotted this star in 2011. All things considered, this is a very lucky observation. We see this star’s spiral arms face-on. In space, stars are oriented in all sorts of ways with respect to Earth, so this face-on find is serendipitous.

The observation has an element of serendipity in another way. That is, astronomers weren’t looking for spiral arms when they masked the brightness of SAO 206462 in order to obtain this photo. They were looking, instead, for distant planets with the Subaru Telescope. Instead of planets, they found a star with spiral arms.

The disk around SAO 206462 is apparently twice as wide as the orbit of Pluto. Theoretical models suggest that the spiral arms could be formed from two planets orbiting this star. How did the spiral structure come to be? As I said at the top of this post … nature loves spirals.

Will astronomers discover more spiral stars? In astronomy and all science, once a lucky discovery reveals something new, we frequently begin to find many more examples. They will not all be face-on to Earth, though, so the image at the top of this post of SAO 206462 is likely to remain an object of unique beauty for some years to come. Enjoy. And by the way, here’s a video from NASA on this star!

Bottom line: SAO 206462 appears to be a relatively young star with a spiral structure surrounding it. Theories suggest there are at least two planets in this system, and that their presence is contributing to the spiral shape of the gas surrounding this star.

November 1, 2011

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Deborah Byrd

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