NASA's Hubble space telescope has spotted a weird star in our galaxy and has been nicknamed "nasty" owing to its behaviour never seen before.
The hefty, rapidly ageing star "Nasty 1" may represent a brief transitory stage in the evolution of extremely massive stars.
First discovered several decades ago, "Nasty 1" was identified as a Wolf-Rayet star, a rapidly-evolving star that is much more massive than Sun.
The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.
But "Nasty 1" does not look like a typical Wolf-Rayet star.
Hubble revealed a pancake-shaped disk of gas encircling the star.
The vast disk is nearly two trillion miles wide.
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Based on current estimates, the nebula surrounding the stars is just a few thousand years old and as close as 3,000 light-years from the Earth.
According to astronomers, this disc is the result of an exceedingly rare occurrence wherein two Wolf-Rayets form within the same solar system and one star's hydrogen fuel is siphoned off by its smaller companion.
"We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction," explained study leader Jon Mauerhan from the University of California-Berkeley in a statement.
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.
"What evolutionary path the star will take is uncertain, but it will definitely not be boring," the authors noted.