Astronomers discover 'first of its kind' star system with three Suns using NASA's TESS

In a 'first-of-its-kind' discovery, a team of amateur astronomers has found a star system that has not one, not two but three suns. Dubbed TIC 470710327, this tertiary star system is unique because the three stars are more massive than usual and are tied together in an extremely compact orbit. According to the observations from NASA's TESS (Transiting Exoplanet Survey Satellite), two of the stars at the center are orbiting each other whereas the third one orbits the pair.

How was the star system discovered?

The tertiary star system was discovered when a team of citizen scientists was skimming through the data collected by TESS. Speculative of the amount of luminosity being detected by the NASA satellite, the astronomers initially thought that the system was a stellar binary, a system of just two stars. However, further assessment of the data and identification of the anomalies in the detection confirmed that the system actually contains three. 

According to the astronomers, the inner binary star system has a combined mass twelve times greater than the sun in our solar system and they both orbit each other in approximately one Earth day. The outer star, on the other hand, is much more massive, having a mass 16 times greater than the sun and orbits the binary pair every 52 days, the experts noted in their study published in the Monthly Notices of the Royal Astronomical Society. 

Theories on the formation of the star system

Alejandro Vigna-Gomez, an astrophysicist at the Niels Bohr Institute at Denmark's University of Copenhagen said that there are three theories that could explain the formation and evolution of this star system. The first theory says that the bigger star orbiting the smaller stars formed first, however, this theory stands weak as the formation of a bigger star would have ejected material strong enough to disrupt the formation of a binary system that close.

The second explanation is that the binary and the third star formed separately but eventually got locked owing to the strong gravitational pull they experienced from each other. And the third theory says that besides the binary system, two stars merged into one to become the outer, bigger star, suggesting that this system might have had four Suns. 

"Maybe there are more compact systems buried in the data. What we really want to know is whether this kind of system is common in our universe", Bin Liu, a postdoc fellow at the Niels Bohr Institute said in an official statement.