Astronomers have made an astounding discovery of a one-of-a-kind star system that has never been seen before. The system TIC 470710327 contains three massive stars, with two binary stars orbiting around a third tertiary star. The binary stars combined have the mass equivalent to 12 times that of our Sun, while the tertiary star alone is as massive as 16 Suns combined.
“As far as we know, it is the first of its kind ever detected,” said Alejandro Vigna-Gomez, a postdoctoral researcher at the Niels Bohr International Academy. “We know of many tertiary star systems (three star systems), but they are typically significantly less massive. The massive stars in this triple are very close together — it is a compact system.”
While scientists have observed trinary star systems, as they are sometimes called, such star systems have large distances between the orbiting stars. Most multi-star systems are present in what is known as hierarchical star systems, where the stars are divided together into smaller groups which then orbit the centre of mass of the system with minimal tidal interaction between the orbits.
In the case of a trinary star system, a pair of usually binary stars orbits around each other while a tertiary star orbits around the centre of mass from a larger distance than the orbit of the binary star.
Shorter distances in such systems mean that the orbits of different stars interact violently, which can result in highly unstable orbits resulting in the ejection of one of the stars eventually. Some other well-known trinary star systems include Polaris, the North Star, which contains a primary star Polaris Aa with its smaller companion star Polaris Ab, which then orbits with the Polaris B at a much larger distance.
Located close to the constellation of Cassiopeia, Vigna-Gomez and fellow postdoctoral researcher Bin Liu ran over 100,000 simulations to understate how this exotic system came to be. They theorised that the largest star formed first but that would have disrupted the binary system. Or the binary system and tertiary star formed separately but drifted to each other because of gravity. But Vigna-Gomez and Liu believed that the system formed from two sets of binary stars, so four stars in total, with one of the pairs merging together to form a larger star.
“There are two ways in which we can prove or disentangle our theory on this formation. One is studying the system in detail and the other is to make a statistical analysis on a population of stars,” Vigna-Gomez explained.
“If we go to the system in detail, we shall have to rely on the expertise of an astronomer. We already have some preliminary observations, but we still need to go through the data, and make sure we are interpreting it well,” Vigna-Gomez added.
