Astronomers have found a triple star system that is different from any other they have seen before. The odd trio of stars is much bigger and closer together than a normal triple system. This could be because they once had a fourth sibling, which was eaten by one of the others.
The triple, or tertiary, star system is called TIC 470710327. It was found using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), which orbits Earth. The three stars have a hierarchical structure, which means that in the center of the system, a pair of binary stars circle each other, and a third star orbits the central pair.
Not many systems have three stars: NASA says that as many as 10% of all star systems in the universe could be tertiary. In September 2021, astronomers saw for the first time that a single exoplanet was going around a tertiary system. This suggested that life might exist in these systems.
On the other hand, TIC 470710327 is different from all other known tertiary systems because of its shape and size. Because the stars are much bigger than most stars in a tertiary system, the three of them are much closer together than usual. This is because their gravitational pull is stronger than usual.
The two stars at the center of TIC 470710327 have a combined mass about 12 times that of the sun, and they orbit around each other in a little more than a day. The outer star is much bigger than the inner one. It weighs about as much as 16 suns and goes around the binary pair once every 52 days, which is very quickly considering how big they are.
The researchers want to keep looking for tertiary systems that are both big and close together, so they can find out if this type of system is common or not.