Scientists working with the Hubble Space Telescope stumbled across a peculiarly behaving massive star. Known as Nasty 1 (or NaSt1), the rapidly aging star is believed to be involved in what astronomers call cosmic cannibalism.
Nasty 1 was first discovered five decades ago, when scientists studying the night’s sky catalogued NaSt 1 as being a Wolf-Rayet star. These particular types of stars are massive in size and evolve quickly by burning through their rich hydrogen-filled outer layers and uncovering their helium inner cores.
Although Wolf-Rayet stars aren’t uncommon, Nasty 1 is.
Recent pictures that Hubble took of NaSt1 showed that the star did not appear as they had expected. Instead of being enveloped in twin lobes of gas, as other Wolf-Rayet candidates are, Nasty displayed gigantic gas disk. Astronomers believe that this disk spans out approximately 2 trillion miles.
“We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction,” paper lead author, Jon Mauerhan said,
This enormous disk may suggest that Nasty is, in fact, part of a binary star system and that its companion may be the suspected cannibal that is devouring Nasty and scattering cosmic debris.
There are several scenarios attempting to explain how Nasty 1 formed. But Mauerhan and his team’s proposition involves the swift evolution of a massive star. After depleting most of its outer-layer of hydrogen, the star swells and allows the remaining hydrogen to be susceptible to gravitational stripping.
Its stellar companion can now become the “cannibal” and gain mass while depleting Nasty’s hydrogen envelope.
Such a find is making astronomers particularly enthusiastic, especially since this particular evolutionary phase is short-lived. According to Maurerhan, binary star systems only spend a hundred thousand years in this phase but that the resulting disk of dust may only be observable ten thousand years (or even less).
If Mauerhan and his colleagues are right, we may be witnessing a rare sighting. The disk surrounding Nasty may be just a couple of thousand years old, allowing astronomers to gain further insight into how Wolf-Rayet stars form.
“We think there is a Wolf-Rayet star buried inside the nebula, and we think the nebula is being created by this mass-transfer process,” Mauerhan added.
Astronomers have had a difficult time in surprising just the right moments and Nasty may have just provided the right opportunity for study.
Mauerhan and his team’s results were published in this month’s Notices of the Royal Astronomical Society.
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