High-Mass Stars May Form as Twins: Binary Systems More Common Than Thought

It turns out that there may be far more binary stars in our universe than astronomers once thought. It turns out that high-mass stars are rarely solitary, which means that heavy stars may already form as twins.

"A few years ago, it began to emerge that high-mass stars, which are about one hundred times as heavy as our sun, preferably occur in the form of binary stars," said Rolf Chini, one of the researchers, in a news release. "I used to think: if you know how a single star works, you also know how a binary star works. However, this is wrong."

In this case, the researchers employed the Very Large Telescope in order to analyze 800 high-mass stars. In the end, they found that over 90 percent of these stars turned out to be multiple systems, consisting of between two and four stars that orbit each other.

In order to actually see these stars, they split the light of the stars into different wavelengths. A star's chemical composition determines at which wavelengths it emits light; this is referred to as spectral lines. By analyzing these spectral lines, researchers can tell whether an object is a single star, or several stars.

So why have astronomers not known this before now?

"Generally, those stars are so close to each other that they can't be distinguished as two discrete points," said Chini in a news release.

In fact, the researchers found that the heavier a star, the higher probability that it isn't alone. Star partners that have similar masses occur together, which means that it's very possible that these stars first emerge as twins. In other words, the celestial object originates from gas and dust clouds which become dense. Then, in the final stage, this dense cloud splits into similar-sized parts.

The findings reveal a bit more about these high-mass stars. More specifically, they show how astronomers should be on the lookout for more than one star when dealing with a high-mass star; it's likely that it's not alone.