Scientists are getting an up-close-and-personal look at the formation process of a Wolf-Rayet star, thanks to a peculiar little star in the Milky Way called “Nasty 1.” Astronomers recently imaged Nasty 1 with the Hubble telescope and were incredibly surprised to discover that they may be witnessing a short-lived process of stellar cannibalism.
Gizmodo reports that astronomers used the Hubble telescope to take images of a Wolf-Rayet star in our galaxy nicknamed “Nasty 1.” The star gets its nickname from its catalog name, NaST1. Typically, Wolf-Rayets are large and rapidly evolving stellar bodies. They are formed when they shed their hydrogen-filled outer layers, which exposes their bright core. These bright stars are common throughout the universe, but Nasty 1 was proving to have some unusual characteristics. The most recent photos proved no different, with scientists left scratching their heads when a large disc-shaped gas cloud was found to be orbiting the star.
As the astronomers noted, Wolf-Rayet stars typically have twin lobes of gas flowing from opposite sides. However, when Hubble images returned of Nasty 1, scientists did not see twin lobes. Instead, they saw a disc of gas orbiting the star. The disc wasn’t small, either. The gas disc is an astonishing 2 trillion miles wide, and may be the proof scientists needed to prove that Wolf-Rayet stars could form from stellar cannibalism that occurs during binary interaction. Jon Mauerhan from UC Berkeley notes that astronomers rely on just a handful of examples of this interaction to go off of because the process is incredibly short-lived.
“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.”
Therefore, it is pretty amazing that scientists would find a Wolf-Rayet star in the midst of this process right in our own celestial backyard within the Milky Way. The National Monitor notes that the evolution of Nasty 1 may prove to be incredibly exciting for astronomers who can get an up-close look at exactly what processes take place in the Wolf-Rayet formation.
The data may also show that the leading cause of Wolf-Rayet star formation is not stellar winds, as previously thought, but instead binary-interaction. So what does the future hold for Nasty 1 if it is in fact being consumed by a nearby binary companion ? Scientists say that hypothetically, as Nasty 1 evolved, it began to swell as its outer hydrogen envelope was loosened by gravitational stripping. The nearby star then began consuming the hydrogen envelope. If this scenario is true and continues to play out, Nasty 1 will eventually be entirely consumed by its parasitic companion star and the larger star will be transformed into a Wolf-Rayet. However, the question remains: how many Wolf-Rayet stars were created from cannibalistic roots and how many were formed from the traditional stellar wind theory? Scientists may soon have a better estimate thanks to the Hubble telescope and Nasty 1.
[Image credit: NASA, ESA, and G. Bacon]
