There may be anti-matter stars in the Milky Way.

Out of about 100 billion stars in our galaxy, no more than 14 can be manufactured from anti-matter. That's the result of a new study that scoured the Milky Way for signs of antistars — which are identical to regular stars save for the fact that they

would burn antimatter at their cores.

Although the results were for the most part empty this time, the researchers have not yet completely ruled out the existence of entities, the presence of which would change a great deal on our understanding of the universe.

The recent search for ancestors can be traced back to 2018, when a $1.5-billion experiment called the Alpha Magnetic Spectrometer (AMS) that's attached to the International Space Station captured a few examples of what might be antimatter.

Antimatter is exactly the same as ordinary matter, but its charge is inverted, so the antimatter equivalent of positively charged protons is negatively chargedcharged antiprotons. In this case, the AMS detected what resembled antihelium, whose nucleus is made up of two antiprotons and two antineutrons.

Cosmic rays can sometimes strike ordinary matter and produce simple anti-matter particles, such as antiprotons and positrons—the inverted version of an electron. But no known process can create something complex like antihelium, Simon Dupourqué, a PhD candidate in astrophysics at the Université de Toulouse in France, said Live Science.

He and his colleagues then asked themselves precisely where this antihelium came from. While physicists are reasonably certain that no large pockets of antimatter exist in the universe, some theorists have suggested that bits of the charge-reversed material could have collected into star-like objects, essentially forming antistars.

Antistars would fuse antihydrogen to anti-helium to produce light, but otherwise they would look pretty ordinary. "If these objects existed, there could be no distinction between them and an ordinary star," said Dupourqué.

But when antimatter and regular matter meet, they annihilate violently, leaving only gamma rays in their wake. Thus, ordinary matter floating in the cosmos in the form of gas and dust would strike these antistars, generating an excess of gamma radiation, declared Dupourqué.

By combing through data from NASA's Fermi gamma-ray telescope, he and his co-authors uncovered 14 examples of small compact objects shining brightly in gamma rays that didn't show up in other star catalogs, meaning scientists don’t know what they are. That might turn them into potential antistar candidates. Their findings were published on 20 April in the magazine Physical Review D.

The crew isn't claiming they're antistars yet. "They are far more likely to be anything else," said Dupourqué, such as previously unknown gamma-ray emitters such as powerful pulsars or distant active galactic nuclei. If they were antistars, "it would change the way we think the universe came together," he said.

This is because cosmologists think that soon after the Big Bang, nearly equal quantities of matter and antimatter were created. These twin materials crushed together in a spectacular energy stream, leaving behind mostly matter, which was created in slightly higher proportions, according to a CERN explanatory.

No one knows how or why more matter was formed, creating what is known as the matter-anti-matter asymmetry problem. If antistars existed, it could mean that some of this original antimatter was able to survive longer than scientists previously believed.

A great deal more work would have to be done, including follow-up observations with future telescopes, to confirm or rule out the antistar explanation, Vivian Poulin, an astrophysicist at the Montpellier Universe and Particles Laboratory in France who wasn't involved in the research, told Live Science.

Some of the antimatter in the early universe might have existed in large pockets that could have collapsed down into star-like objects, though this is not part of astronomers' standard picture of the moments after the Big Bang, he added.

Original publication on Live Science.