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Hubble Space Telescope discovers one-of-a-kind star

It's nickname is 'Nasty 1'

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This visible-light image taken by NASA's Hubble Space Telescope reveals a pancake-shaped disk of gas around an extremely bright star in our Milky Way galaxy, about 3,000 light-years from Earth.

The disk glows brightly in the light of ionized nitrogen.

The central star is nicknamed "Nasty 1," derived from its catalog name of NaSt1. First discovered several decades ago, Nasty 1 is thought to be a Wolf-Rayet star, a massive, rapidly evolving star weighing well over TEN TIMES the mass of our sun.

But Nasty 1 doesn't look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, which is a Wolf-Rayet candidate. Nasty 1 is losing its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.

The star is thought to have a companion, and gravitational interactions between them may have created the gas disk. Both stars are heavily obscured by gas and dust in the disk. Hubble observations suggest that, as Nasty 1 sheds its weight, some of the mass is falling onto a companion star and some is leaking into space, forming the disk. The vast structure is nearly 2 trillion miles wide. The disk is clumpy because astronomers think the outbursts occur sporadically. The knot at left of center is an unusually bright clump of gas. The image is tinted blue to bring out details in the disk.

Astronomers were surprised to find the disk-like structure, which has never been seen before around a Wolf-Rayet star in our galaxy. The star may represent a brief transitory stage in the evolution of massive stars.

Follow Paul Gross on Twitter: @PGLocal4


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