Case of the missing stars: At least 800 stars have quietly disappeared in the last 70 years, say scientists

Imagine gazing at the night sky, night after night, locking eyes with a single star that twinkles just for you. And then, poof! Gone. No goodbye note, no flickering farewell — just an empty patch where your starry friend once resided. And for those believing that stars represent the souls of their ancestors, this could come as a rude shock.

While this sounds like a Star Wars plot, we do seem to be having a problem with stars just disappearing into the darkness of late.

Based off of the little sense we’ve made of the hot mess that is the cosmos, there are two ways stars disappear: the no-drama kind simply dim over time, while the bigger stars like to go out with a bang and explode as supernovas. However, astronomers have documented around 800 cases of stars just vanishing without a trace over the last 70 years!

While the mysterious disappearances have had scientists scratching their heads, we finally have reason to reopen this cold case. Recently, astrophysicists at the University of Copenhagen's Niels Bohr Institute shared their study of a rather unusual binary star system that gives credence to the theory that some massive stars can entirely collapse and become black holes without all the fanfare of a supernova explosion.

This “complete collapse” occurs when stars collapse under their own weight in the final phases of their lives.

"Were one to stand gazing up at a visible star going through a total collapse, it might, just at the right time, be like watching a star suddenly extinguish and disappear from the heavens," said study co-author Alejandro Vigna-Gómez at the Niels Bohr Institute. "The collapse is so complete that no explosion occurs, nothing escapes and one wouldn't see any bright supernova in the night sky."

The binary star system that the team looked at, VFTS 243, hangs somewhere at the edge of the Milky Way. It has a large star and a black hole ten times larger than our Sun orbiting each other every 10.4 days. Here’s where it gets interesting: when they tried looking for signs of a supernova explosion (which might’ve resulted in the black hole), they ran into a brick wall.

Usually, a supernova would be accompanied by baryonic mass ejecta or natal kicks — which accelerate orbiting objects. But it was not so in this case. And this lead them to explore the idea of the star losing most of its mass-energy via neutrinos, perhaps even by gravitational waves to some extent, making the extreme scenario of complete collapse into a black hole becomes a possibility.

If their hypothesis is right, this could be one of the reasons, probably even the only reason, for the disappearance of large stars.