Two volunteer astronomers have confirmed the existence of a Neptune-like planet that has four suns, making it the first quadruple star system ever discovered. The planet, which is 5,000 light years away from Earth, closely orbits one pair of stars, which in turn forms a unit that revolves around a second pair at a distance of around 1,000 AU.


Illustration by Ron Miller.

The amateur astronomers took part in the Planet Hunters citizen science project, and were able to confirm the system with help from professionals in the U.K. and U.S.


Binary star systems are fairly common, but it's exceptionally rare for them to feature planets. As a result, astronomers have speculated that the odds of finding a planet in a quadruple system were extremely low. This new find, therefore, came as a complete surprise.

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The discovery of the planet, which has been named PH1 after the Planet Hunters project, was made by Kian Jek of San Francisco and Robert Gagliano from Cottonwood, Arizona, who were using Planethunters.org, a website that utilizes human pattern recognition to identify planetary transits in data that's made available to the public (specifically, scans that are gathered by NASA's Kepler Space Telescope).

Looking at the data, the duo noticed faint dips in light caused by the planet passing in front of its parent stars. Following their immediate observation and announcement, a team of professional astronomers took over and confirmed the presence of a quadruple system using telescopes on Mauna Kea, Hawaii.


What the astronomers still don't understand, however, is how the gas giant, which is just slightly larger than Neptune, avoids being pulled apart by the intense gravitational forces exerted on it by the four nearby stars. And indeed, the planet's proximity to such large gravity wells place it in an incredibly complex gravitational environment — but it sits in an apparently stable orbit. Lead researcher Chris Lintott from the University of Oxford described it as "really confusing."


Regardless, PH1 has now been classified as the first confirmed planet to orbit an eclipsing binary in a hierarchical quadruple star system. And given that the most distant stars are only 1,000 AU away, the night sky must be nothing short of spectacular.

Details of the study can be found at arXiv.

Top image: Ron Miller; inset image Haven Giguere/Yale.