Two stars of this system are a contact eclipsing binary—a stellar formation in which two stars are orbiting so narrowly together than they share the same atmosphere; from a distance, it would appear as though they’re touching. Contact binaries aren’t uncommon, but this one is distinctive in that it features mostly short orbital period; it takes just six hours for these two stars to circle one another.
As for the other binary, its two separate stars are positioned about 21 billion kilometers from its companion binary, which is a distance slightly larger than Pluto’s orbit around the Sun.
Further study shown a fifth star, up to two billion kilometers away from the separate binary, but it’s not creating any additional eclipses. By studying the system’s light curves and their spectra, the scientists confirmed that they’re all gravitationally bound together in a lone system. A pre-print version can be found at arXiv.