In its continuous quest to serve mankind, the Hubble Space Telescope has made yet another contribution. It captured glimpses of what astronomers believe to be cosmic cannibalism. Hubble just captured new images of a gigantic star called Nasty 1, much larger than our solar system’s sun.
Nasty’s behavior has had experts baffling. Surrounded by a bright, hot, helium core, Nasty 1 seems to be eating itself. Its massive disk of gas spans out over 3 million miles around Nasty.
This sinister, enigmatic star resides in our own galaxy. A Wolf-Rayet star, Nasty 1 is engulfed in a flat disk of gas 1,000 times larger than that of our solar system.
Astronomers first discovered Nasty 1 (or by its catalog name NaSt1) a few decades ago. Wolf-Rayet stars represent rapidly evolving, highly active stars which quickly lose their outer layers of hydrogen and expose their bright helium core.
“We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction,” Jon Mauerhan explains.
Committing what astronomers best describe as an act of stellar suicide, Nasty 1 may be showcasing a fleeting transitory stage in a massive star’s evolution.
Jon Mauerhan, University of California, explains that our galaxy holds few (if any) similar examples. Because this hydrogen-consuming phase is extremely short, lasting a couple of hundred thousand years, astronomers have had a hard time locating such intriguing phenomena. He adds that there is a specific timeframe over which resulting disks are visible.
The exact manner in which such massive stars evolve is still unknown to scientists. Whether solar winds are responsible for hulling the star’s helium core or whether a cannibalistic companion star takes part in siphoning off the star’s outer layers remains to be determined.
In Nasty’s case, the latter scenario seems more plausible.
Astronomers believe that inside the nebula there is a Wolf-Rayet star. A mass-transfer process, they explain, is responsible for creating the nebula in the first place. It’s precisely this cosmic cannibalism that makes Nasty’s name so befitting.
The traditional wind model that experts had previously considered didn’t add up. All Wolf-Rayet stars couldn’t have formed like that because mass loss didn’t appear to be constant. And in such binary star systems, mass exchange is an essential part of the process.
Herein lies the exquisite value of observing Nasty 1: it’s difficult to catch binary stars in this specific phase.
Witnessing the evolutionary path that Nasty 1 goes on, astronomers explain, will be as thrilling as its discovery. One possible course is that of Eta Carinae, where giant eruptions could cause the mass-gaining cannibalistic companion to become unstable. Another involves Nasty 1 turning into a supernovae and exploding.
Or, Nasty 1 could merge with its companion, but every scenario depends on the two star’s orbital evolution, the duration of the mass transfer as well as each star’s lifespan following the mass transfer’s end.
Image Source: Slash Gear