Hubble Observes Unique Star Nicknamed Nasty 1

Posted on May 23, 2015

Vast disc of gas surrounds the star Nasty 1

Astronomers using Hubble are observing a star that has been nicknamed Nasty 1. It is a hefty and rapidly aging star located in our Milky Way galaxy. The name is a play on the star's catalog name of NaSt1.

Astronomers say the Nasty 1 star may represent a brief transitory stage in the evolution of extremely massive stars. It was identified as a Wolf-Rayet star when it was first discovered decades ago. These types of stars evolve rapidly and quickly lose their hydrogen-filled out layers. The result is a star that has its super-hot and extremely bright helium-burning core exposed.

Nasty 1 is not behaving like a typical Wolf-Rayet star should. Astronomers studying the star say there should be twin lobes of gas flowing from opposite sides of the star like has been observed in other Wolf-Rayet stars. Astronomers could not find this feature in Nasty 1. Instead, there is a pancake-shaped disk nearly two trillion miles wide encircling Nasty 1. This disc is over 1,000 times the diameter of our solar system.

Jon Mauerhan of the University of California, Berkeley is the leader of the study. He says in a statement, "We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction. There are very few examples in the galaxy of this process in action because this phase is short-lived, perhaps lasting only a hundred thousand years, while the timescale over which a resulting disk is visible could be only ten thousand years or less."

The vast disk of gas around Nasty 1 is depicted in the above artist's illustration. A larger version of the above image can be found here on

Artist's Illustration: NASA, ESA, and G. Bacon (STScI)

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