For the first time ever, researchers have found a multiple-star system in the process of forming. While scientific hypotheses exist about how such system forms, the observations of the team in this case will provide the first solid evidence.

The researchers were looking at a gas cloud about 800 light years away where they knew a young protostar was forming. Unexpectedly they found that the cloud also contained three dense areas that they believe will collapse into stars in about 40,000 years. The researchers believe that three of the four stars will survive, eventually forming a solar system with three suns.

“Seeing such a multiple star system in its early stages of formation has been a longstanding challenge, but the combination of the Very Large Array (VLA) and the Green Bank Telescope (GBT) has given us the first look at such a young system,” said Jaime Pineda, of the Institute for Astronomy, ETH Zurich, in Switzerland told phys.org.

In addition to the VLA and GBT the team used the James Clerk Maxwell Telescope (JCMT) in Hawaii to study the Barnard 5 (B5) gas cloud. B5 is located in a stellar nursery in the Perseus constellation.

The team used the VLA to map radio emissions from methane molecules. The data showed them that B5’s gas filaments are fragmenting and those fragments are beginning to form new stars.

“We know that these stars eventually will form a multi-star system because our observations show that these gas condensations are gravitationally bound. This is the first time we’ve been able to show that such a young system is gravitationally bound,” said Pineda.

The fragmentation of gas filaments is one of the ways that has been hypothesized for the formation of multiple-star systems. Other suggested methods include the fragmentation of the main gas core, gravitational capture and the fragmentation within a disk of matter orbiting a young star.

“This provides fantastic evidence that fragmentation of gas filaments is a process that can produce multiple-star systems. We’ve now convincingly added fragmentation of gas filaments to this list,” said Pineda.

The data suggests that the gas condensations in B5 will produce stars from one-tenth to one-third the size of our sun, separated from one another by 3,000 to 11,000 times the distance from the Earth to the sun.

The researchers predict that, eventually, the resulting system will consist of an inner binary system being orbited by a distant third star. The fourth star will not remain part of the system. This will result in a system similar to the Alpha Centauri system which has the same makeup.

“Nearly half of all stars are in multiple systems, but catching such systems at the very early stages of formation has been challenging. Thanks to the combination of the VLA and the GBT, we now have some important new insight into how multiple systems form,” said Pineda.

While it is possible that multiple star systems can have planets, those planets may not enjoy the stability of a single star system. With the heat and gravitational forces of three stars, they would certainly have a difficult time supporting life as we know it. However, it is a big universe and planets in multi-star systems do exist, with triple star system HD 188753 Ab being one example.

The results of this research can be found in the February 12 edition of the journal Nature.

The next step for the team will be to use the new capabilities of the VLA and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to look at other star forming systems.