Giant stars eat their neighbors

The researchers focused on how regular B stars and Be stars move in the sky. If the star is part of a binary star system, it will wobble slightly, orbiting around a center of gravity that it shares with its sister star.

In advance, researchers expected that oscillations would be more common among Be stars, precisely because, according to theory, they needed a sister star to absorb matter from, but surprisingly, the data showed otherwise.

Binary star systems appear to be the most common among regular B stars.

Triple stars breed cannibals

Rather than abandon their theory, the researchers chose to expand it. Using other sets of data, they investigated whether Be stars have companions farther than the typical distance between two sister stars.

Now the numbers suddenly showed something completely different: the further away researchers looked, the more common it was for Be stars to have companion stars.

This discovery led researchers to a new theory. They now believe that Be stars form in three-star systems, two of which orbit so close to each other that the oscillations are not visible to us. Therefore, the two neighboring stars appear in our telescopes as one star, moving in a straight line across the sky.