Antistars
Could a star exist that is made entirely from Antimatter, so mostly anti-hydrogen and anti-helium.
Theoretically at least such a star could exist, and if we were to observe such a star close up, it wouldn't look particularly different from the normal stars we see, the only difference would be, whenever normal matter came into contact with it, it and an equal amount of the star would be destroyed.
A team of Astronomers in France have been looking for the tell tale signs of stars that produce higher than expected gamma radiation, which could indicate an antimatter reaction occurring and have found 14 candidates.
The team accept that there's many other theories that could explain the gamma radiation other than an antistar, and that an antistar that doesn't come into regular contact with normal matter isn't going to produce any either. So it's almost impossible to prove with any certainty.
Even so, if we were able to discover such a star, it's implications for how the universe came together would be fairly profound.
Source : https://www.newscientist.com/article/2275563-antimatter-stars-may-lurk-in-the-solar-systems-neighbourhood/
