'The vampire's assistant'

Be stars have always been a fascinating mystery to astronomers. They are a subset of bright B-type stars. Unlike typical B-type stars, Be stars rotate very rapidly and create rings of matter around their orbits, a phenomenon not seen in other types of stars and still largely unexplained.

By analyzing data from two powerful satellites, Gaia and Hipparcos, researchers from the University of Leeds (UK) have shown that Be's unusual characteristics are due to its interaction with its two companions.

The "monster" star Be and its victim star in the distance, stripped of their outer layers. (Graphic: ESO)

Be stars are considered a kind of cosmic "vampire." The theory suggests that this bizarre type of star develops from a binary system consisting of two stars orbiting a common center.

The predator and its smaller companions become its victims. It sucks in matter from its victims, creating a ring of matter around itself, while simultaneously accumulating angular momentum to increase its rotational speed.

In the new study, scientists focused on one problem: The extent of binary star systems orbiting the same center seems too large for the star Be to hunt down and "feed" its companion.

That's a difficult question to answer, because only 28% of Be stars are identified with a companion star. One theory is that the companion star has become too faint to observe after a long period of being "drained" of energy.

Considering data on other types of stars where a star is stripped of matter by a companion star, scientists concluded that Be is likely part of a system with more than two stars.

In this case, the third star acts as the "vampire's aide," orbiting in a larger orbit outside of Be and the "victim" star.

The chaos within the triple star system gave this hidden helper the opportunity to push the victim star closer to Be, while itself moving further away.

The sufficiently close distance made it easier for Be to "feed," allowing it to develop better and reach the "monster" state that astronomers often observe.

(Source: Nguoi Lao Dong Newspaper)

Source: https://vtc.vn/phat-hien-loai-vat-the-thien-van-moi-tro-thu-cua-ma-ca-rong-ar836783.html