The discovery of a very unusual triple star system was announced earlier this year by scientists at the Niels Bohr Institute at the University of Copenhagen. This unusual three-star system consists of two stars that orbit each other, with a third much bigger star that orbits this pair.
Royal Astronomical Society's Monthly Notices published this research in June.
Alejandro Vigna-Gomez, corresponding author of the study and postdoc at the Niels Bohr International Academy, in a press statement said, "As far as we know, it is the first of its kind ever detected. 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", the Indian Express reported.
The pair of stars orbiting around each other at the centre of the system has a mass twelve times that of the Sun. The binary also has an orbital period, which is the same length of time as a day on Earth. Although the central binary appears to contain some giant stars, the tertiary star is even more massive with a mass 16 times that of our Sun.
The inner system has a circular orbit with the tertiary star circling the pair close to six times every year. When the size of the star is taken into consideration, this is quite fast. When this system was detected for the first time, it was thought to be only a stellar binary.
But then, while sifting through a public data set from NASA's TESS (Transiting Exoplanet Survey Satellite) observatory, a community of amateur astronomers discovered something unusual. They saw some anomalies in the findings, and as it turns out, what were initially thought to be two stars were actually three stars.
Multiple explanations are considered by the researchers on how this system might have formed. After more than 100,000 computer simulations, it was concluded that two binary systems may have initially formed before one of the binary systems merged to form a massive tertiary star.