Astronomers Spot the Tiniest Packed Quadruple Star System

Using NASA’s TESS data from 2019–2024, astronomers identified TIC 120362137 as the most compact 3+1 quadruple star system: an eclipsing binary eclipsed by a third star, plus a distant fourth star with a 1,045.5‑day orbit—the shortest outer period observed in such a configuration. The inner three stars are packed within Mercury’s orbital distance while the outer companion sits near Jupiter’s orbit. The team’s models suggest the inner trio will merge into a white dwarf in ~300 million years, leaving a double white-dwarf system with a ~44‑day orbit.