Discovery of a perfect sphere glowing in Milky Way poses several questions

Astronomers have spotted a perfect sphere floating in space. It is a bubble which is believed to comprise remnants of a supernova and is in the Milky Way. However, the problem is figuring out how it was formed. Scientists are also struggling to learn its age. Seeing how perfectly spherical the bubble is, a team led by astrophysicist Miroslav Filipović of Western Sydney University in Australia has named the object Teleios - Greek for "perfection".

The discovery is part of an analysis that has been submitted to the Publications of the Astronomical Society of Australia.

Teleios is unlike other such objects found in the universe. The Australian Square Kilometre Array Pathfinder (ASKAP) has located several circles in the sky, but Teleios has thrown up quite a few problems for scientists. It is closer and smaller, but it is difficult to ascertain how how far away it is, which has consequently created a problem about understanding its origin.

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The sphere glows faintly only in radio wavelengths, leading scientists to conclude that it is a remnant of a Type Ia supernova – one of the brightest types of supernova in the universe. This type of supernova occurs when a white dwarf locked in a binary orbit with another star pulls in a lot of material from it, causing it to exceed its mass limit and explode.

How far is the sphere? How big is it? How old?

About its distance, researchers think it could be either around 7,175 light-years from Earth, or around 25,114 light-years. Figuring out its size is a problem if its exact distance is not known. Depending on how far it is, its size and age would differ widely. If it is at the nearest distance mentioned above, then the supernova remnant would be 46 light-years across. At the greater distance, it would be 157 light-years across.

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A supernova remnant has material that keeps expanding. So to know its age, one must know its size as well. A supernova remnant that is closer suggests it is younger since it hasn't had much time to grow, less than 1,000 years. At a greater distance, it would have to be more than 10,000 years old.

Could it be a 'zombie' star remnant?

Scientists applied another scenario - one where it is a remnant of a Type Iax supernova. In this case, the white dwarf isn't destroyed entirely, but leaves behind a 'zombie' star remnant. Teleios could fit the bill, but it needs to be around 3,262 light-years away for this scenario. It would also be smaller, about 11 light-years across.

"We have made an exhaustive exploration of the possible evolutionary state of the supernova based on its surface brightness, apparent size and possible distances," the researchers write.

It is a perfect sphere, and might seem like a rarity. However, scientists say such symmetrical supernovas can be found in empty spaces. It will continue to expand and lose the perfection when it reaches the point of fragmentation.