Most Tightly Packed Quadruple Star System
Astronomers spotted an unprecedented four-star system with three stars in stable orbits and a fourth at a distance comparable to Jupiter's orbit in our solar system. This discovery provides new insights into stellar dynamics and challenges our understanding of how multiple star systems can remain stable. The tight configuration defies previous models of gravitational interactions.
This quadruple star system, identified as TIC 120362137, is located in the constellation Cygnus. Its unique 3+1 configuration, with three central stars and a more distant fourth, is exceptionally rare among the 101 potential quadruple systems recently identified using data from NASA's Transiting Exoplanet Survey Satellite (TESS). The inner trio of stars is packed into a space smaller than Mercury's orbit around our Sun. These three stars are all more massive and hotter than our own sun. In contrast, the fourth, more distant star is similar in mass and temperature to the Sun. An international team led by Tamás Borkovits from the University of Szeged in Hungary utilized TESS data gathered between 2019 and 2024 to make the discovery. The presence of the fourth star was revealed through irregularities in the timing of the other stars' eclipses, a method known as Eclipse Timing Variations (ETV). The orbital period of the outermost star is the shortest ever recorded for such a system, at just 1,045.5 days. The two innermost stars orbit each other every 3.3 days, and the third star orbits this pair every 51.3 days. This compact arrangement challenges current understanding of how such systems can form and remain gravitationally stable over long periods. Astronomers have modeled the future of TIC 120362137, predicting that in about 300 million years, the three inner stars will merge into a single, massive white dwarf. The fourth star will also evolve into a white dwarf, and the two resulting white dwarfs will continue to orbit each other every 44 days.
